Open access peer-reviewed chapter

The Nutritional Challenges in Dysphagia: Not Only a Matter of Nutrients

Written By

Isabelle Germain

Submitted: 26 April 2022 Reviewed: 04 May 2022 Published: 05 July 2022

DOI: 10.5772/intechopen.105167

From the Edited Volume

Dysphagia - New Advances

Edited by Monjur Ahmed

Chapter metrics overview

219 Chapter Downloads

View Full Metrics


Oropharyngeal dysphagia can significantly affect food ingestion. Texture-modified foods and thickened fluids are proposed to alleviate this difficulty. The nutritional density of adapted foods is often insufficient to maintain adequate nutritional intakes. The current scientific knowledge relies on a weak correlation between clinical assessment and meals consumed by patients as well as few clinical trials to support the efficacy of any treatment. The negative organoleptic perceptions associated with dysphagia diets further exacerbate undernutrition and malnutrition. Over the years, scientist in food science, nutritionists, psychologists and other health professionals have proposed parameters when formulating novel foods for the treatment of dysphagia. Beyond the nutritional composition of adapted foods for the treatment of dysphagia, this chapter will present multidimensional factors affecting food intake, sensory evaluations, rheological parameters as well as the available research to date with respect to optimizing nutritional treatment of dysphagia. To date, extrapolation to everyday food formulations remains a real challenge. To ensure success, thorough, individualized nutritional care plans need to be implemented and monitored regularly. An international knowledge transfer database must be considered to help document the innovations proposed in texture-modified foods and thickened fluids in order to benefit patients of all ages and origins.


  • nutrition
  • rheology
  • sensory evaluation
  • dysphagia

1. Introduction

The contextual application and impact of nutritional interventions in the clinical treatment of dysphagia have been studied in the scientific literature [1, 2, 3, 4]. Articles published as early as 1946 are presenting difficulties in swallowing due to either tonsillectomy, achalasia, myasthenia gravis, dysphagia lusoria—vascular compression of the esophagus—malignant causes and focused mainly on the esophageal phase of food ingestion [5, 6, 7, 8]. An interest in difficulty in chewing and eating was also brought forward in the 1960s by the challenges of swallowing in neurological diseases or post-stroke patients [9, 10, 11]. Nearly 60 years later, the complexity of food ingestion in adults afflicted by deglutition disorders, more specifically dysfunctions of the oral and oropharyngeal regions, continues to be an important clinical challenge. The multifaceted aspects of food perception, mastication, preparation and propulsion of the bolus for an effective deglutition is still a major preoccupation for patients, families and caregivers.

The natural and reflex driven act of feeding one-self in adulthood is in fact an intricate emotional, sensory and neuromuscular achievement. It is directed by visual, olfactory, tactile and gustatory stimulations leading to pleasure and social interactions. Feeding one-self needs to meet much more than just pure physiological goals, particularly in healthcare.

“In spite of food fads, fitness programs, and health concerns, we must never lose sight of a beautifully conceived meal.”

– Julia Child.

The difficulty to chew and swallow foods and liquids, known as dysphagia, often leads to malnutrition, impaired immune system and pneumonia [12, 13, 14, 15]. In fact, presbyphagia (gradual and subtle decrease in swallowing capacity) and persistent undernutrition have been linked to sarcopenia and, more specifically pulmonary sarcopenia [16, 17, 18, 19, 20].

Several medical conditions such as head and neck cancers, cerebrovascular accidents, dementia, neurodegenerative diseases and aging could lead to dysphagia. Contingent to the underlying etiology and the evaluation/reporting method, reported prevalence of oropharyngeal dysphagia vary greatly, ranging from 11.4 to 91.7% in various assessed populations [21, 22]. Finally, dysphagia could improve, remain stable or worsen, needing recurrent assessments and adaptation of nutritional treatments (Figure 1). The conditions presenting some of the highest prevalence rates are observed in the very old frail populations presenting neurodegenerative conditions [21, 22].

Figure 1.

Nutritional intervention route in dysphagia context.


2. Nutritional interventions

The past century has seen a remarkable evolution for human nutrition. Nutritional requirements for various population groups were adopted for different parts of the world and used to assess quality of food intake or food service delivery of well balanced meals in hospitals, schools, or daycare as well as or nutrition labeling of commercial food products [23, 24, 25]. Detailed nutritional values and composition of foods can now be more comprehensively assessed. Therefore, menus’ macro and micronutrients are regularly being calculated for individual needs. Additionally, several databases exist to assess food intake in a wide array of clienteles (infants, children, athletes, elderly, etc.), food types or food service contexts [26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38].

It is regularly stated that, dysphagia leads to diminished food intake, poor functional status and increased risk of pneumonia. To improve the situation, foods and liquids are gradually adapted in texture or consistency to offer softer, moist and cohesive boluses and meet the needs of the patients’ changing medical condition. In fact, it is now internationally recognized that various texture-modified foods (TMF) and thickened fluids (TF) are considered the cornerstone of clinical treatment and should be carefully evaluated [39]. Interestingly, in research studies investigation appetite and food intake in relationship to food oral processing, a meta-analysis published by Krop and colleagues noted that increased food oral processing (chewing) reduced food intake (−0.28 effect size; 95% CI: −0.36, 0.19; I2 statistic = 61.52%) and curbed appetite (−0.20 effect size; 95% CI: −0.30, 0.11; I2 statistic = 0%) [40]. Given this evidence, the decreased oral processing required to ingest TMF should be linked to improved oral food intake which is mostly sought after in dysphagia nutritional intervention. Additionally, thickening agents used to increase the consistency and reduce flow velocity are known to contribute to nutritional density [41]. So, shall we see an instant improvement? Not, according to the literature.

For the past 20 years, nutrient composition of institutional diets or TMF dysphagia diets have been repeatedly identified as deficient in energy and macro- or micronutrients [42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52] and remain a well known contributing factor of undernutrition and sarcopenia. Internationally, professional organizations are suggesting guidelines for better healthcare nutrition, including dysphagia nutritional care plans [53, 54, 55, 56, 57]. Fortification in energy, protein content or micronutrients of TMF, and the use of snacks are suggested to improve nutritional status [58, 59, 60]. But, sensory characteristics of TMF and TF such as taste, mouthfeel and appearance are regularly perceived negatively [61, 62, 63, 64, 65] and this nutritional treatment is seen as a psychosocial burden by staff and patients [66, 67, 68, 69, 70, 71]. The challenge lies in adapting the foods offered to patients presenting dysphagia to optimize/improve nutritional content while maintain acceptable sensory characteristics!

Very few randomized clinical trials looking at comprehensive food intake reports for MTD and TF are found in the literature [72, 73, 74]. They were conducted in elderly populations, for a limited assessment time and are of small sample sizes. They did take in consideration complete dietary intakes, including oral nutritional supplements (ONS), meals and snacks. Detailed quantitative dietary assessments using weighed food records and done over several days in order to reflect usual intake are complex and time consuming [75]. This could explain the paucity of publications.

First in 2006, a small randomized controlled trial of 12 weeks was conducted by Germain et al. in frail elderly residents in a long-term care (LTC) facility (Treatment Group: n = 8; age: 82.5 ± 4.41 years, weight 55.9 ± 12.1 kg, BMI 22.4 ± 3.93; Control Group: n = 9; age, 84.6 ± 3.81 years, weight 54.3 ± 7.49 kg, BMI 21.2 ± 2.31). Prior to randomization, all participants were assessed for oropharyngeal of dysphagia and TMF and TF were prescribed as needed. The control group received usual TMF and the treatment group received reshaped pureed or minced foods. Intakes were calculated using 3-day weighed food records at Baseline, Midway and End points. The average weight in the treated group augmented compared to the control group (3.90 ± 2.30 vs. −0.79 ± 4.18 kg; p = 0.02). Furthermore, the treated group had an improved intake of total energy, proteins, fats, total saturated fats, monounsaturated fats, potassium, magnesium, calcium, phosphorus, zinc, vitamin B-2, and vitamin D compared to control subjects (p ≤ 0.05) [72].

In 2017, following a 20-week intervention, Côté et al. also demonstrated improved intakes in a multi-center study of 15 elderly LTC residents (Treatment Group: n = 7). In this study, participants were assessed for oropharyngeal dysphagia to ensure adequate prescription level of TMF and TF. The control group received institutional TMF and the treatment group received reshaped pureed or minced foods (Épikura©). Proportions of food intakes were measured by comparing pictures of the content of the tray, before and after the meals (2 consecutive days; lunch and supper meals; excluding supplements and drinks). Although participants’ body weights remained unchanged, the an increase in energy (p = 0.004), carbohydrate (p = 0.04) and lipid (p = 0.001) intakes in the treated group was documented [73].

Lastly in 2019, Reyes-Torres et al. implemented a controlled TMF and TF diet (n = 20 participants) to be compared to isocaloric standard diet (n = 20 participants) for 12 weeks. All participants received instructions in regards to swallowing rehabilitation techniques. Daily energy and protein intakes were assessed by 24-h multiple-step recalls and calculated using Food Processor Nutrition Analysis® software. In the intervention group, results revealed improved energy intakes (29 ± 10 to 40 ± 15 kcal/kg, p = 0.009) and protein intakes (1.3 ± 0.6 to 1.8 ± 0.7 g/kg, p = 0.03). Likewise, body weight were increased (56 ± 10 to 60 ± 10 kg, p < 0.001) as well as handgrip strength (18 ± 11 to 21 ± 13 kg, p = 0.004). Control group parameters remained unchanged. Therefore it appears that, although isocaloric to the standard pureed diet, better texture controlled pureed foods and TF allowed for improved dietary intakes and overall physical health status.

More recently, in a 12-week intervention study involving 50 elderly individuals living in a LTC facility (age: 89.12 ± 4.18 years), Rondanelli and colleagues also demonstrated that meal appreciation and nutritional status can be improved with tailored pureed texture meals [76]. This research team assessed meal intake with the Comstock Method of visual estimations of food waste [77] as an alternative to weighed dietary intake measures. It is noteworthy to mention that digital imaging methods to assess food intakes in various contexts (school cafeterias, restaurants, hospitals, etc.) have improved since their development in the early 1980s [78]. Visual estimations increasing used in research as they have the potential to help document food intake in larger groups with excellent agreement with the direct observational method, good agreement for between observers assessments comparison and presents very high intra-rater agreements [79, 80, 81, 82, 83].

Finally, in a case-crossover study published in 2022, Bayne et al. implemented sensory-enhanced, fortified snacks (quick-dissolving crisps, puree dips, and dry soup blends) for 8 weeks. The snacks improved the quality of nutritional intake among nursing home residents [84].

The presence and severity of dysphagia should prompt an individualized, nutritionally adequate and texture/consistency adapted nutritional interventions care plan to maintain or improve nutritional status and overall health of these patients. Although intuitively sound, few randomized clinical trials or interventions studies can be found using a clearly identified adapted nutritional intervention in association to specific severity of dysphagia. These rare and modest investigations seem to confirm that, other than using oral nutritional supplements, maintaining or improving nutritional density of foods provided by food services is possible. However, given the unfortunate poor quality of the research to date, systematic reviews repeatedly request more and better investigations [50, 54, 85, 86].

Admittedly, several confounding variables affect any nutritional research protocols: age groups, oropharyngeal or esophageal dysphagia, sample sizes, clinical settings, cultural reality, foods and ONS offered, number of meals assessed, dietary intake assessment method, duration of study, initial nutritional and clinical status, disparity in assessment approaches and measured outcomes, etc. The impact of nutritional interventions is challenging to measure (Table 1) [13, 76, 87, 88, 89]. Often, assessments have been conducted in elderly populations, possibly due to the convenience of studying cohorts in a more controlled environment. Conversely, clinical conclusions on the efficacy of these trials in younger populations should carefully extrapolated.

Vucea et al. [13]
Cross-sectional study
n = 337
Regular diet
n = 139
Minced diet
n = 68
Pureed diet
Age = 86.8 ± 7.8 y
32 LTC facilities
InterRAI LTCF Cognitive Scale
MNA-SF score were lower for patients on MTF, dementia, ONS, assistance to fed or poor oral health
MNA-SF score were higher for patients with micronutrient supplements or family assistance for meals.
Malnutrition risk increased when diet texture prescription was changed from regular to minced diet
Malnutrition risk increased when diet texture prescription was changed from regular to pureed diet
Shimizu et al. [87]
Retrospective cohort
n = 218 with pneumonia
Age = 82.9 ± 9.8 y
TMD group
Multiple stages TMD (M-TMD) group
Food Intake Level Scale
Japan TMD Scale
The M-TMD were related to the maintenance or improvement of swallowing capacity and nutritional status
Nutritional intake not assessed
Dysphagia severity not assessed
Razalli et al. [88]
Cross-sectional study
n = 95
TMF diet
Age: 64.2 ± 16.7 y
Blended diet
Mixed porridge diet
Minced diet
1 day lunch (L) + dinner(D)
Food waste
Food appreciation
Clinical/external factors such as appetite, assistance, time to eat, oral nutritional support
Blended diet
Food waste—lunch: 68.8%
Food waste—dinner: 63.3%
Correlated with variety of food, time to eat meal and appetite
Mixed porridge diet:
Food waste—lunch: 36.3%
Food waste—dinner: 33.9%
Correlated with texture and temperature
Minced diet:
Food waste—lunch: 57.9%
Food waste—dinner: 55.5%
Correlated with appearance, taste, vegetables and chicken/meat/fish
Nutritional intake not assessed
Dysphagia severity not assessed
Endo et al. [89]
Longitudinal study
n = 284
Regular diet
n = 171
TMF diet
Age = 86.5 ± 7.8 y
Duration = 1 year
25 LTC facilities
Severity of dysphagia
Barthelet Index
Total energy intake
Food form
ADL and change in food from regular to TMD form were associated to weight loss
Rondanelli et al. [76]
Intervention study
n = 25 pureed diet
1223 kcal and 44 g protein per meal
n = 25 consistency
controlled MTD
1400 kcal and 53 g protein per meal
All beverages are thickened
Age = 89.2 ± 4.6 y
Meal satisfaction
Food intake
Arm- and calf-circumferences
Blood chemistry
Dysphagia Outcome and
Severity Scale (DOSS) as inclusion criteria
Significant improvements were observed for food intake, meal appreciation,
BMI, arm- and calf-circumferences, MNA, handgrip
Prealbumin and albumin
Folic acid, vitamin D and ionized calcium
PCR and TNF-alpha
Dysphagia severity was assessed but not used to stratify data

Table 1.

Selected nutritional trials in adult patients presenting dysphagia.

Regrettably, dysphagia is too often considered as present or not present in research investigations. As an adapted nutritional individualized treatment, TMF and TF should be selected according to the level of severity of dysphagia. This variable is frequently ignored when evaluating the impact nutritional of treatments whether it is TMF, TF or ONS. Likewise, the severity level of the dysphagia is often extrapolated in observational or epidemiological studies by reporting descriptive aspects of TMF being served to patients [13, 90]. This premise could falsely assume that all participants had been properly assessed or monitored or that all foods were optimally controlled for their texture, consistency or nutrient density. Poorly assessing, documenting and reporting dysphagia severity scale in publications undoubtedly leads to inconsistent results and interpretation. An analogy with optometry assessments can be made. Optometrists will not report poor or good vision. Optometrists will report myopia or presbyopia in well-defined optical units called diopters. Individualized prescription will be proposed and corrective lenses will be provided. Although such precision in dysphagia severity assessment is still difficult to measure for all patients, it must be maintain as part of the assessment evaluation when conclusions are drawn from different trials.

Various dysphagia assessment tools exist: screening tools, bedside assessments or more sophisticated instrumental investigation methods such as surface electromyography (sEMG) biofeedback, manometry, videofluoroscopy or fiberoptic endoscopy evaluations. Clientele, clinical context or availability of expertise and equipment to conduct these tests will determine if they can used or not. Their usefulness and their validity continue to be challenged [91, 92, 93, 94, 95, 96, 97]. The protocols for each evaluation differ. Bolus types and quantities consumed to perform the tests also differ. Additionally, diverse texture modifiers [65, 98] are used to change bolus consistency and texture of TMF and TF. In a clinical context, medications can also require consistency or texture modifications rendering new formulations which are also poorly understood [99]. Finally, and perhaps even more pertinent for nutritional interventions, no publication to date can be found providing a clear relationship between the various boluses provided during these assessments, the modification of consistency and texture occurring during the oropharyngeal phase of swallow and the multitude of foods possibly available at meals. Therefore, these investigation techniques must remain surrogate assessment methods of swallowing capacity and direct extrapolation of the capacity to prepare and swallow various types of bolus can only truly be monitored using a careful diagnostic process and impact of therapeutic approaches, in realistic contextual mealtime conditions, over time (Figure 2).

Figure 2.

Key factors for a meaningful nutritional intervention trial in dysphagia context.

Keeping these limitations in mind, scales evaluating severity of oropharyngeal dysphagia have been validated with various clienteles. Examples of such scales would be the 7-point Dysphagia Outcome and Severity Scale (DOSS) [100], the 7-point Functional Oral Intake Scale (FOIS) [101], the Eating Assessment Tool (EAT-10) [102] and the 10-point observer-rating scale Food Intake LEVEL Scale (FILS) [103] (Table 2). Dysphagia severity scales are hardly ever applied in nutritional interventions or trials. But in 2006, Clavé et al. found a strong correlation between malnutrition and the dysphagia inventory score in 46 participants with brain damage, 46 participants with neurodegenerative diseases and eight healthy volunteers [104]. It could be helpful in future research focused on nutritional interventions to include a severity scale and determine if a correspondence is detectable between nutritional status and dysphagia severity.

Dysphagia Outcome and Severity Scale [100]
(United States)
DOSSDesign intended population: adult, post-stroke
For videofluoroscopy or fiberendoscopy swallow study
Full per-oral nutrition (P.O): normal diet
Level 7: normal in all situations
Normal diet
No strategies or extra time needed
Level 6: within functional limits/modified independence
Normal diet, functional swallow
Patient may have mild oral or pharyngeal delay, retention or trace epiglottal undercoating but independently and spontaneously compensates/clears
May need extra time for meal
Have no aspiration or penetration across consistencies
Full P.O.: modified diet and/or independence
Level 5: mild dysphagia: distant supervision, may need one diet consistency restricted
May exhibit one or more of the following
Aspiration of thin liquids only but with strong reflexive cough to clear completely
Airway penetration midway to cords with one or more consistency or to cords with one consistency but clears spontaneously
Retention in pharynx that is cleared spontaneously
Mild oral dysphagia with reduced mastication and/or oral retention that is cleared spontaneously
Level 4: mild–moderate dysphagia: Intermittent supervision/cueing, one or two consistencies restricted
May exhibit one or more of the following
Retention in pharynx cleared with cue
Retention in the oral cavity that is cleared with cue
Aspiration with one consistency, with weak or no reflexive cough
Or airway penetration to the level of the vocal cords with cough with two consistencies
Or airway penetration to the level of the vocal cords without cought with one consistency
Level 3: moderate dysphagia: Total assist, supervision, or strategies, two or more diet consistencies restricted
May exhibit one or more of the following
Moderate retention in pharynx, cleared with cue
Moderate retention in oral cavity, cleared with cue
Airway penetration to the level of the vocal cords without cough with two or more consistencies
Or aspiration with two consistencies, with weak or no reflexive cough
Or aspiration with one consistency, no cough and airway penetration to cords with one, no cough
Non-oral nutrition necessary
Level 2: moderately severe dysphagia: Maximum assistance or use of strategies with partial P.O. only (tolerates at least one consistency safely with total use of strategies)
May exhibit one or more of the following
Severe retention in pharynx, unable to clear or needs multiple cues
Severe oral stage bolus loss or retention, unable to clear or needs multiple cues
Aspiration with two or more consistencies, no reflexive cough, weak volitional cough
Or aspiration with one or more consistency, no cough and airway penetration to cords with one or more consistency, no cough
Level 1: severe dysphagia: NPO: Unable to tolerate any P.O. safely
May exhibit one or more of the following
Severe retention in pharynx, unable to clear
Severe oral stage bolus loss or retention, unable to clear
Silent aspiration with two or more consistencies, nonfunctional volitional cough
Or unable to achieve swallow
Functional Oral Intake Scale [101]
(United States)
FOISDesign intended population: adult, post-stroke
Tube dependent
Level 1: No oral intake
Level 2: Tube dependent with minimal/inconsistent oral intake
Level 3: Tube supplements with consistent oral intake
Total oral intake
Level 4: Total oral intake of a single consistency
Level 5: Total oral intake of multiple consistencies requiring special preparation
Level 6: Total oral intake with no special preparation, but must avoid specific foods or liquid items
Level 7: Total oral intake with no restrictions
Eat Assessment Tool [102]
(United States)
EAT-10Design intended population: adult, various clinical diagnoses
Developed by Expert Panel
10 questions pertaining to eating difficulty EAT-10 score of 3 or higher: abnormal
Food Intake LEVEL Scale [103]
FILSDesign intended population: palliative care patients
No oral intake
Level 1: No swallowing training is performed except for oral care.
Level 2: Swallowing training not using food is performed.
Level 3: Swallowing training using a small quantity of food is performed.
Oral intake and alternative nutrition
Level 4: Easy-to-swallow food less than the quantity of a meal (enjoyment level) is ingested orally.
Level 5: Easy-to-swallow food is orally ingested in one to two meals, but alternative nutrition is also given.
Level 6: The patient is supported primarily by ingestion of easy-to-swallow food in three meals, but alternative nutrition is used as a complement.
Oral intake alone
Level 7: Easy-to-swallow food is orally ingested in three meals. No alternative nutrition is given.
Level 8: The patient eats three meals by excluding food that is particularly difficult to swallow.
Level 9: There is no dietary restriction, and the patient ingests three meals orally, but medical considerations are given.
Level 10: There is no dietary restriction, and the patient ingests three meals orally (normal).

Table 2.

Scales of severity of dysphagia - assessment tools.

Given all the existent caveats limiting the bedside and clinical assessment of dysphagia, nutritional interventions need to be prescribed to alleviate and compensate for the decrease in food intake. Notwithstanding the possible enteral nutritional avenue, texture modified diets, oral nutritional supplements, enriched snacks are some of the options proposed [21, 50, 60, 76, 85, 86, 101, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117].


3. Influential factors associated to eating

Eating is indispensable for subsistence. Therefore, it is a crucial component of the evolution of the human kind. As part of the essential evolutionary process, eating has taken various forms and adaptation has been linked to our survival.

Food choices and eating patterns are affected by several key elements such as biological influences (appetite, taste, hunger), psychological influences (mood or stress), socio-cultural determinants (family, peers, income, skills) and learnt behaviors [118, 119]. Côté et al. have depicted multiple factors to consider when providing adapted foods to the elderly. These factors remain intact, if not more important, once dysphagia becomes symptomatic (Figure 3) [120].

Figure 3.

Interaction model of key factors affecting feeding in the context of dysphagia in the older adult population.

In the context of texture-modified foods and thickened fluids for the nutritional treatment of dysphagia, the appreciation of foods is often described as a burden [49, 66, 70, 71, 86, 121]. The reasons behind this present state of affairs are very complex and possibly imbedded in human survival programming itself.


4. Starting at the beginning: human evolution and food intake

The need of water and food was stated as a key necessity in the Maslow Hierarchy of Needs [122]. As humanoids evolved, the feeding techniques and the human chewing capabilities have evolved and adapted through time. Paleoanthropologist Dr. Rick Potts is the founder of the Human Origins Program at the Smithsonian’s National Museum of Natural History, Washington, DC [123]. Potts describes the evolution of the human cranium developing from a small brain case and slope-like face to our current species with the largest brain case and the smallest face. The mandibular bone (not shown on the video) would have also changed in shape and strength affecting the capacity to chew foods and prepare the food bolus for swallowing.

Ledogar and colleagues [124] studied the morphology and the facial biomechanics of cranium specimens from various regions around the globe. Using computational biology, the research group created a model (named ALL-HUM) incorporating several characteristics of crania to which they allocated human bone tissue and masticatory muscle force values in order to predict cranial mechanics and calculate strains and bites forces of our ancestors. The masticatory gracilization over time of the human face was less stiff than the chimpanzee comparatives but were efficient in bite force application. These findings support the hypothesis that consumption of less mechanically challenging foods or the origination of extra-oral processing techniques (tools and cooking) accompanied these morphological changes. Humans adapted in several ways to evolved in various regions of the globe. One impressive adaptation was food preparation as well as feeding and chewing techniques as it is essential to survival of the species.

4.1 Taste perception

The biomechanics of human masticatory abilities are definitely important elements of feeding. However, feeding evolution is not only linked to our capacity to mechanically break down or process foods. It is associated to an array of sensations which also guide humans in accepting or refusing the ingestion of substances. It is believed that taste perception is an adaptive response [125] to assessing nutritional content or toxicity of foods. Initially believed to be spatially mapped on the tongue, it is now understood that taste receptors are found across the tongue [126]. In fact, located in the oropharyngeal region, the primary tastes of sweet, bitter, salty, sour and umami receptors could have helped humans in detecting acceptable foods sources. One type of taste receptor cell was identified for each of the sweet and umami tastes. For salt and sour tastes, possibly more than one are involved. However, bitter taste is detected by 25 different types of cell receptors [127, 128]. Therefore, primates and humans are capable to detect bitterness which prevents the consumption of possible toxic plants [129]. Animal studies have shown that, although specific taste buds regenerated at a high turnover rate, they maintain the capacity to reconnect to the central nervous system due to labeled line wiring. Essentially, labeled line wiring allows the bitter taste center to convey and perceive only bitter peripheral signal or the sweet center carry only sweet signal. The molecules responsible for directing these gustatory nerves are known as semaphorins and are proteins involved in neuronal axon guidance which permit high specificity [130, 131, 132, 133]. Consequently in humans, taste perception is highly regulated and neurologically wired to allow innocuous ingestion of a wide array of substances.

New investigations pertaining to the microbiome have associated oral microbiota composition and with taste perception and reported food intake. Although providing exploratory results, it is proposed that the oral microbiota could also be affecting taste and smell perception as well as overall appetite [134, 135, 136, 137, 138, 139, 140].

4.2 Mouthfeel and texture perception

Ingestion of food is also guided by mouthfeel and texture perceptions as well as appreciation of the masticated bolus. Oral processing is a complex progression of neuromuscular interactions which prepares and assess food prior to swallowing. As food is being broken down and imbibed with saliva, it is in contact with the oral sensory receptors and an integrated sensory evaluation of tastes, volatile compounds and texture will occur [141, 142].

Electromyography (EMG) has been used to assess electric activity of the main masticatory muscles in healthy participants. Coupled to chewing cycle counts, tongue mobility, tongue pressure, salivation or videofluoroscopy studies, the mechanistic involved pre- and peri-swallowing can be assessed [143, 144, 145, 146, 147, 148]. In a study looking at gels and sols, muscle activity required until swallowing appeared to be well correlated with the required force deployed for large compression deformation which occurs at the initiation of mastication [145]. Tournier and colleagues observed large inter-participant variation both for salivation and oral processing after 5 healthy participants masticated 4 breads of different textures and compositions [146]. Mori and colleagues studied the laterality of the posterior tongue movement in 20 young and health adults by [147]. Gummy jelly, sponge cake and mashed potatoes were assessed as representative of gradient mastication intensity requirements at the initiation, middle and end of mastication stages. For the purpose of the study, the participants were asked to masticate only on the right side or only on the left side. They measured a more intense EMG activity on the side of mastication for the gummy jelly and documented that tongue activity was affected by the food texture. Finally, Matsuo and colleagues investigated the masticatory function of 22 young participants an 32 community-dwelling older individuals of either normal or oral hypofunction. For their investigation, the test samples were a control meatloaf, meatloaf containing lotus root, control chicken ball or chicken ball with almonds slivers (10 g per bite). The documented mean EMG amplitudes and integrated EMG activity were lower for control samples which were softer test foods. Oral functions, including dental condition, appeared to decline with age and would have influenced the assessed mastication capacity [148].

The characterization of the biomechanics of bolus preparation and its impact on swallowing capacity is still being investigated [149, 150, 151] and remains limited in application for daily clinical investigations or association to diversified menu items around the globe. Few foods have been assessed. However, the variability in bolus process are highlighted and the impact could be important.

Individual physiognomy, quality of dentition and capacity to prepare foods for deglutition are only one part of the complex equation. The foods and liquids consumed bring their share of complexity. The lubrication of the bolus is also dependent on salivation. Intra-oral assessment of bolus texture and correlation to sensory perceptions are challenging.


5. Development of adapted texture-modified foods

5.1 Sensory evaluation

Acceptance by consumers of food products is a main priority for the food industry. Development of new products is time consuming and costly. However, the formal study of sensory evaluation of foods is a science with a relatively recent history. As stated by M.A. Drake, sensory evaluation is a “collection of techniques that seek to differentiate between a range of products based on all of their sensory characteristics and to determine a quantitative description of all the sensory attributes that can be identified, not just the defects” [152]. Methods such as discrimination testing (Is there a difference between 2 formulations?), acceptability (Which food would you prefer? Rating scales of relative dislike and like), descriptive sensory evaluation (How can we discriminate between a range of products based on all of their sensory characteristics?) have provided additional tools for application in research, product development, and marketing [152, 153]. Important developments in the science of sensory evaluation were initially triggered in the U.S. by the desire to optimize food intake in U.S. armed forces [152, 154, 155, 156]. With the creation of the food acceptance program in 1945, the U.S. Army Quartermaster Food and Container Institute (Chicago) had four main divisions which were food habit studies, psycho-physiological studies, organoleptic studies and statistical theory. In 1949 and 1950, psychologists David Peryam and Norman Girardot were hired to lead the Food Acceptance Research Branch. As measurement is essential to building comparative datasets, the staple nine-point hedonic scale (Table 3) was developed to assess food acceptance and preference [157, 158]. This scale remains in use today to asses customers appreciation of assorted food products such as chips [159], beef sausage using pigeon pea as binding agent [160] or yoghurt [161].

Like extremely
Like very much
Like moderately
Like slightly
Neither like nor dislike
Dislike slightly
Dislike moderately
Dislike very much
Dislike extremely

Table 3.

9-point hedonic scale [157].

In the past, food development for the treatment of dysphagia customarily stemmed from clinical settings [44, 72, 162]. Researchers state that TMF and TF are deemed to be at the core of the nutritional treatment for dysphagia diets [65, 163], therefore, it is essential to evaluate the sensory profile if optimal ingestion is to be achieved. Limited publications have assessed sensory characteristics of TMF or TF. Pureed peaches [164], pureed carrots [165, 166, 167], meats [166, 167], soups, pates and timbales [167] were assessed primarily by healthy young adult for sensory perception. Thickened fluids have been studied more extensively: water with and without barium, lemon flavored water, juices, milk and infant formula [63, 168, 169]. But, even fewer publications have included participants with impaired swallowing [164, 166]. Studies are mainly conducted with the participation of young healthy adults. To be fair, several neurological diseases affect oral expression or comprehension of instructions which could render consumer assessments difficult. However, when recommending approaches to improve nutritional intakes and adherence to a proposed dysphagia diet, customer appreciation—likes and aversions of patients—should be at the core of the plan. More sensory research should be done with TMF and TF to help in developing complete, nutritious, appetizing and varied menu plans.

5.2 Rheological evaluation

Nutritional interventions for the treatment of dysphagia can take various forms and should progress with the medical conditions. Foods are molecularly and structurally elaborate and diverse. Oral nutritional supplements, texture-modified foods and thickened fluids often require the addition of the texture modifying agents which only adds to the complexity of these matrices. Comparing foods items is challenging in clinical trials. Over time, terminology and assessment methods have been proposed [170]. Two major milestones in the evolution of dysphagia diets development were the National Dysphagia Diet (NDD) [171] in 1999 and the International Dysphagia Diet Standardization Initiative (IDDSI) [39] in 2015.

Based on the work of food scientists Russell H. Mills [172] and Don Tymchuck [173], the NDD was the first diet to propose a quantifiable measure to assess flow of TF. Viscosity ranges were determine to discern different 3 different levels of consistency for fluids. Concepts of food texture such as adhesiveness, cohesiveness, firmness and springiness were also suggested to describe and classify TMF in 3 categories (Table 4).

Fluids unitsDrinks units
(ml after 10 s)
1–50 cP3
50–350 cP
351–1750 cP
≥1750 cP
Slightly thick—level—1
Mildly thick—level—2 Moderately thick—level—3
Extremely thick—level—4
≤1 ml
1–4 ml
4–8 ml
8–10 ml
≥10 ml
NDD level 1: dysphagia-pureedLiquidized—level—38–10 ml
NDD level 2: dysphagia-mechanical alteredPureed—level—4≥10 ml
NDD level 3: dysphagia-advancedMinced & moist—level—5Transitional foods
RegularSoft & bite-sized—level—6
Easy to chew-regular—level—7

Table 4.

Terminology and rheological parameters associated to various levels of dysphagia diets.

National dysphagia diet.

International dysphagia diet standardization initiative.


After an extensive literature review and consultation among researchers, clinicians and industry leaders, the IDDSI group propose a more extensive descriptive framework and classification of the liquids with 5 levels to distinguish fluids and 5 levels for the MTF. A gravity flow test using a syringe is propose to measure liquid flow and 4 levels are recommended (Table 4). The syringe was preferred to other methods such as shear viscosity measurements or the use of empirical tests such as the Bostwick consistometer [174] or the line spread test due to the accessibility and ease of use of the syringe. But, velocity results obtained for various fluids using the IDDSI syringe and the Bostwick consistometer are unexpected and the discriminating capacity of the IDDSI levels remain to be demonstrated (Figure 4). The food texture descriptive parameters are still suggested to explain the MTF. However, other guidelines such as particle size, spoon-tilt test, drip test, fork pressure test and visual cues were added.

Figure 4.

Bostwick flow test and syringe flow test of common products (AAFC—Saint-Hyacinthe Research and Development Center (Canada)—unpublished data).

Both frameworks had important repercussions in the research and industrial arenas. By proposing a standardized terminology and food classification systems, these approaches helped researchers, clinicians, patients as well as the food industry to classify foods and allow better description of clinical protocols and comparison of interventions. Still, clinical trials will be required to assess their impact on nutritional status of patients suffering from dysphagia. The main novelty of these proposed frameworks was the use of rheology.

Rheology is the science of deformation and flow of matter [175]. In the context of oropharyngeal dysphagia, fluids and semi-solid foods are the object of interest. Two (2) extensive reviews helped the understanding of the science of rheology specifically in the perspective of oropharyngeal dysphagia treatment [176, 177].

First, the review published by Gallegos et al. [176] focused on the rheology of fluids. Providing a short review of basic rheological concepts, they present fundamental parameters impacting the flow of fluids such as stress, strain and strain rate (Table 5), type of fluids Newtonian, non-Newtonian, viscoplastic fluids as well as time-dependent viscous flow behavior, shear viscosity and extensional viscosity. In light of their work, it becomes evident that a bolus will undergo major pressure and deformation before and during the course of deglutition. The various forces applied (i.e. shear rates) throughout swallowing are challenging to measure and have not been clearly established. For the moment, a shear rate of 50 s−1 is generally used in the literature. Salivary alpha-amylase and the presence of contrast fluids (barium) are also addressed since their presence impacts the bolus texture parameters and rheological behavior as the bolus is being processed orally prior or during swallowing.

Stress (τ or σ)Force per unit areaPascals (Pa)
Strain (ϒ)Relative variation of position in the flow directionNon dimensional
Strain rate (‘ϒ)Strain variation over times−1

Table 5.

Fundamental dynamic and kinematic variables of flow [176].

These variables are temperature, pH, pressure and time dependent in Non-Newtonian fluids.

Swallowing imposes a stress on the bolus and deformation of the fluid occurs. The composition of the bolus will influenced its rheological behavior.

Raheem and colleagues proposed a comprehensive review of the publications addressing the TMF. They present the various tests, both sensory and instrumental, available to the food industry to measure textural characteristics of foods. Similarly to the work done with TF, the rheological assessment of TMF is scare in the literature. According to this review, a better understanding of the complex food matrices used in the nutritional treatment of dysphagia, by all stakeholders, must take place to improve TMF.

5.3 Bridging the gaps

As early as 1963, Dr. Alina Szczesniak [178, 179] led the food industry in bridging the gap between the emerging technologies of the times and the sensory evaluations of foods. By developing standard rating scale to describe the mechanical characteristics of foods that were now assessed by texturemeters, Dr. Szczesniak demonstrated that although more repeatable and quantifiable, the data obtained for instruments remained insignificant in product development if they were not linked to human assessment and ratings. This vision of correlating instrumental and sensory assessments should inspire more future research in nutritional treatment for dysphagia. The recent ‘mouthfeel wheel’ terminology should be a step in the right direction [180].


6. Conclusion

Dysphagia is a condition affecting dietary intake. Although often underestimated, chronic undernutrition can exacerbate frailty and can lead to poor physical condition, declined immune system, sarcopenia and pneumonia. In view of the current literature, nutritional content, texture and consistency as well as appearance of texture-modified foods should be improved. An assortment of foods and fluids should be investigated to reflect more realistic food intake patterns. Above all, a personalized nutritional intervention is essential to prevent health decline.

Eating is indispensable to subsistence in addition to being a critical part of the social aspect of life. New texture-modified foods should be developed with the involvement of individuals affected by dysphagia to improve taste, textural profiles and overall acceptability. Clinical trials should improve documentation of the dysphagia severity level, nutritional intervention (foods/fluids offered) and food intake prescribed, nutrient density, satisfaction of meals and adaptation to patients nutritional needs. Research done to date, although essential to understanding this complex health issue, is still theoretical and lacks integration of expertise. We must improve clients/patients consultation. A large number of foods and fluids are required to build an nutritious and appealing menu which is an essential element to improve intakes. An open-sourced international clinical database for nutritional interventions in dysphagia, similar to existing food composition databases [181, 182, 183, 184], would be a valuable tool to build a strong resource base. While archiving details of various food or fluids formulations, nutritional values and rheological parameters (when available), this compendium would support knowledge transfer and benefit food/pharmaceutical industries, researchers, clinicians as well as clients.

Finally, clinicians and research teams must continue to progress in bridging the knowledge gap between the foods used to evaluate dysphagia severity (with and without barium), the foods and the fluids available for nutritional interventions and recommendations for the development of commercial foods available for oropharyngeal dysphagia treatment.



First, I wish to thank Sophie Turcot for her support in organizing and maintaining our laboratory facilities as well as her reliability and diligence in her scientific work. I wish to acknowledge Francis Villeneuve for his methodical approach in the multiple rheological tests conducted. Finally, I wish to extend my most sincere gratitude to Amélie Giroux, Patricia Décarie and Vivianne Chagnon of the Association professionnelle des nutritionnistes experts en dysphagie for their patient-centered approach to clinical nutrition.


Conflict of interest

The authors declare no conflict of interest.


Notes/thanks/other declarations

The author is co-inventor of the CA2467625C patent. The current assignee of this patent is Her Majesty the Queen in Right of Canada. 


  1. 1. Ninfa A, Crispiatico V, Pizzorni N, Bassi M, Casazza G, Schindler A, et al. The care needs of persons with oropharyngeal dysphagia and their informal caregivers: A scoping review. PLoS ONE. 2021;16(9 September):1-20. DOI: 10.1371/journal.pone.0257683
  2. 2. Rodd BG, Tas AA, Taylor KDA. Dysphagia, texture modification, the elderly and micronutrient deficiency: A review. Critical Reviews in Food Science and Nutrition. 2021:2-16. DOI: 10.1080/10408398.2021.1913571
  3. 3. Ueshima J, Momosaki R, Shimizu A, Motokawa K, Sonoi M, Shirai Y, et al. Nutritional assessment in adult patients with dysphagia: A scoping review. Nutrients. 2021;13(3):1-15. DOI: 10.3390/nu13030778
  4. 4. Wakabayashi H, Kishima M, Itoda M, Fujishima I, Kunieda K, Ohno T, et al. Diagnosis and treatment of sarcopenic dysphagia: A scoping review. Dysphagia. 2021;36(3):523-531. DOI: 10.1007/s00455-021-10266-8
  5. 5. Gross RE. Surgical treatment for dysphagia lusoria. Annals of Surgery. 1946;124:532-534. DOI: 10.1097/00000658-194609000-00008
  6. 6. Johnstone AS. Dysphagia due to causes other than malignant disease. Edinburgh Medical Journal. 1946;53:160-172
  7. 7. Stinson WD. Myasthenia gravis of muscles of deglutition. Memphis Medical Journal. 1946;21:120
  8. 8. Thorpe PA. A case of dysphagia in a woman of 78 cured by tonsillectomy. British Medical Journal. 1946;1(4453):723. DOI: 10.1136/bmj.1.4453.723
  9. 9. Jones FA. Dysphagia. The Practitioner. 1946;157:219-221
  10. 10. Kalinovskaya IY, Lavrova SV. Disorders of deglutition in some diseases of the central nervous system (Russian). Klinicheskaia Meditsina. 1973;51(9):69-74
  11. 11. Jones RF. Stroke rehabilitation. Part II. Special considerations. The Medical Journal of Australia. 1975;2(21):799-801. DOI: 10.5694/j.1326-5377.1975.tb106314.x
  12. 12. Eglseer D, Lohrmann C. Dysphagia and malnutrition in older hospitalized adults. Aktuel Ernahr Med. 2016;41(6):450-455. DOI: 10.1055/s-0042-119779
  13. 13. Vucea V, Keller HH, Morrison JM, Duizer LM, Duncan AM, Carrier N, et al. Modified texture food use is associated with malnutrition in long term care: An analysis of making the Most of mealtimes (M3) project. The Journal of Nutrition, Health & Aging. 2018;22(8):916-922. DOI: 10.1007/s12603-018-1016-6
  14. 14. Kiesswetter E, Hengeveld LM, Keijser BJ, Volkert D, Visser M. Oral health determinants of incident malnutrition in community-dwelling older adults. Journal of Dentistry. 2019;85:73-80. DOI: 10.1016/j.jdent.2019.05.017
  15. 15. Furuya J, Suzuki H, Hidaka R, Nakagawa K, Yoshimi K, Nakane A, et al. Factors related to oral intake of food by hospitalized patients with malnutrition under the care of a nutrition support team. International Journal of Environmental Research and Public Health. 2021;18(21):1-11. DOI: 10.3390/ ijerph182111725
  16. 16. Hansen T, Nielsen RL, Houlind MB, Tavenier J, Rasmussen LJH, Jørgensen LM, et al. Dysphagia prevalence, time course, and association with probable sarcopenia, inactivity, malnutrition, and disease status in older patients admitted to an emergency department: A secondary analysis of cohort study data. Geriatrics (Switzerland). 2021;6(2):1-14. DOI: 10.3390/GERIATRICS6020046
  17. 17. Azzolino D, Damanti S, Bertagnoli L, Lucchi T, Cesari M. Sarcopenia and swallowing disorders in older people. Aging Clinical and Experimental Research. 2019;31(6):799-805. DOI: 10.1007/s40520-019-01128-3
  18. 18. Wakabayashi H. Role of nutrition and rehabilitation in the prevention and management of sarcopenia and frailty. In: Recent Advances of Sarcopenia and Frailty in CKD. Singapore: Springer; 2020:117-138. DOI: 10.1007/978-981-15-2365-6_8
  19. 19. Nagano A, Wakabayashi H, Maeda K, Kokura Y, Miyazaki S, Mori T, et al. Respiratory sarcopenia and sarcopenic respiratory disability: Concepts, diagnosis, and treatment. The Journal of Nutrition, Health & Aging. 2021;25(4):507-515. DOI: 10.1007/s12603-021-1587-5
  20. 20. de Sire A, Ferrillo M, Lippi L, Agostini F, de Sire R, Ferrara PE, et al. Sarcopenic dysphagia, malnutrition, and oral frailty in elderly: A comprehensive review. Nutrients. 2022;14(5):1-23. DOI: 10.3390/nu14050982
  21. 21. Gallegos C, Brito-de la Fuente E, Clavé P, Costa A, Assegehegn G. Nutritional aspects of dysphagia management. Advances in Food and Nutrition Research. 2017;81:271-318. DOI: 10.1016/bs.afnr.2016.11.008
  22. 22. Xavier JS, Gois ACB, de Carvalho Palhano Travassos L, Pernambuco L. Oropharyngeal dysphagia frequency in older adults living in nursing homes: An integrative review. CODAS. 2021;33(3):1-12. DOI: 10.1590/2317-1782/20202020153
  23. 23. Tsuboyama-Kasaoka N, Takizawa A, Tsubota-Utsugi M, Nakade M, Imai E, Kondo A, et al. Dietary intake of nutrients with adequate intake values in the dietary reference intakes for Japanese. Journal of Nutritional Science and Vitaminology. 2013;59(6):584-595. DOI: 10.3177/jnsv.59.584
  24. 24. Price MY, Preedy VR. Chapter 44 - Dietary Reference Values. In: Metabolism and Pathophysiology of Bariatric Surgery: Nutrition, Procedures, Outcomes and Adverse Effects. London: Elsevier Inc.; 2017. pp. 399-417. DOI: 10.1016/B978-0-12-804011-9.00030-3
  25. 25. Powers HJ. Approaches to setting dietary reference values for micronutrients, and translation into recommendations. The Proceedings of the Nutrition Society. 2021;80(3):365-372. DOI: 10.1017/S0029665121000562
  26. 26. Martin CL, Clemens J, Moshfegh AJ. Items designated as fortified: Food and nutrient database for dietary studies (FNDDS), 2015-2016. Journal of Food Composition and Analysis. 2019;84:1-4. DOI: 10.1016/j.jfca.2019.103255
  27. 27. Delgado JA, Vandenberg B, Neer D, D’Adamo R. Emerging nutrient management databases and networks of networks will have broad applicability in future machine learning and artificial intelligence applications in soil and water conservation. Journal of Soil and Water Conservation. 2019;74(6):113A-118A. DOI: 10.2489/JSWC.74.6.113A
  28. 28. Van Puyvelde H, Perez-Cornago A, Casagrande C, Nicolas G, Versele V, Skeie G, et al. Comparing calculated nutrient intakes using different food composition databases: Results from the European prospective investigation into cancer and nutrition (EPIC) cohort. Nutrients. 2020;12(10):1-14. DOI: 10.3390/nu12102906
  29. 29. Pompeu J, Gerage J, Ometto J. A spatiotemporal database on the energy, macro and micro-nutrients from the Brazilian agricultural production. Data in Brief. 2020;30:1-13. DOI: 10.1016/j.dib.2020.105602
  30. 30. Pehrsson PR, Mitchell DC. Advancing food and nutrient databases through partnerships and technology. Journal of Food Composition and Analysis. 2020;92:1-2. DOI: 10.1016/j.jfca.2020.103527
  31. 31. Jasthi B, Pettit J, Harnack L. Addition of gluten values to a food and nutrient database. Journal of Food Composition and Analysis. 2020;85:1-4. DOI: 10.1016/j.jfca.2019.103330
  32. 32. Fairulnizal M, Gunasegavan RDN, Khalid NM, Balasubramaniam V, Mustar S, Rashed AA. Recent techniques in nutrient analysis for food composition database. Molecules. 2020;25(19):1-45. DOI: 10.3390/molecules25194567
  33. 33. Ma P, Li A, Yu N, Li Y, Bahadur R, Wang Q , et al. Application of machine learning for estimating label nutrients using USDA Global Branded Food Products Database, (BFPD). Journal of Food Composition and Analysis. 2021;100:1-9. DOI: 10.1016/j.jfca.2021.103857
  34. 34. Rodrigues MP, Khandpur N, Fung TT, Sampson L, Oliveira MRM, Willett WC, et al. Development of DietSys: A comprehensive food and nutrient database for dietary surveys. Journal of Food Composition and Analysis. 2021;102:1-8. DOI: 10.1016/j.jfca.2021.104030
  35. 35. Miller V, Singh GM, Onopa J, Reedy J, Shi P, Zhang J, et al. Global Dietary Database 2017: Data availability and gaps on 54 major foods, beverages and nutrients among 5.6 million children and adults from 1220 surveys worldwide. BMJ Global Health. 2021;6(2):1-19. DOI: 10.1136/bmjgh-2020-003585
  36. 36. Drewnowski A. Plant-based milk alternatives in the USDA branded food products database would benefit from nutrient density standards. Nature Food. 2021;2(8):567-569. DOI: 10.1038/s43016-021-00334-5
  37. 37. Ložnjak Švarc P, Jensen MB, Langwagen M, Poulsen A, Trolle E, Jakobsen J. Nutrient content in plant-based protein products intended for food composition databases. Journal of Food Composition and Analysis. 2022;106:1-10. DOI: 10.1016/j.jfca.2021.104332
  38. 38. Pickford C, McCormack L, Liu Y, Eicher-Miller HA. US Department of agriculture food composition databases, the food and nutrient database for dietary studies 2013-2014, and the national nutrient database for standard reference version 28 yield significantly different nutrient totals of food items from eight midwestern food pantry inventories. Journal of the Academy of Nutrition and Dietetics. 2022 (In Press, Corrected Proof):1-10. DOI: 10.1016/j.jand.2022.01.010
  39. 39. Martineau C. International dysphagia diet standardisation initiative: IDDSI framework. Médecine des Maladies Métaboliques. 2015;13(1):101-102. DOI: 10.1016/S1957-2557(19)30036-7
  40. 40. Krop EM, Hetherington MM, Nekitsing C, Miquel S, Postelnicu L, Sarkar A. Influence of oral processing on appetite and food intake—A systematic review and meta-analysis. Appetite. 2018;125:253-269. DOI: 10.1016/j.appet.2018.01.018
  41. 41. Miranda D, Breda J, Cardoso R, Gonçalves N, Caldas AC, Ferreira JJ. Should the energy contribution of commercial thickeners be considered in the nutrition plan of patients with dysphagia? Nutrition in Clinical Practice. 2020;35(4):649-654. DOI: 10.1002/ncp.10408
  42. 42. Wright L, Cotter D, Hickson M, Frost G. Comparison of energy and protein intakes of older people consuming a texture modified diet with a normal hospital diet. Journal of Human Nutrition and Dietetics. 2005;18(3):213-219. DOI: 10.1111/j.1365-277X.2005.00605.x
  43. 43. Patricia Viganó C, Nilian Silva S, Camila Cremonezi J, Guilherme Vannucchi P, Marta CM. Variation in the energy and macronutrient contents of texture modified hospital diets. Revista Chilena de Nutricion. 2011;38(4):451-457. DOI: 10.4067/S0717-75182011000400008
  44. 44. Rocamora JAI, García-Luna PP. Texture modified diet; digestibility, nutritional value, and contributions to menu of hospitals and nursing homes. Nutrición Hospitalaria. 2014;29(4):873-879. DOI: 10.3305/nh.2014.29.4.7285
  45. 45. Ettinger L, Keller HH, Duizer LM. Characterizing commercial pureed foods: Sensory, nutritional, and textural analysis. Journal of Nutrition in Gerontology and Geriatrics. 2014;33(3):179-197. DOI: 10.1080/21551197.2014.927304
  46. 46. Ilhamto N, Keller HH, Duizer LM. The effect of varying ingredient composition on the sensory and nutritional properties of a pureed meat and vegetable. Journal of Nutrition in Gerontology and Geriatrics. 2014;33(3):229-248. DOI: 10.1080/21551197.2014.927307
  47. 47. Keller HH, Carrier N, Slaughter SE, Lengyel C, Steele CM, Duizer L, et al. Prevalence and determinants of poor food intake of residents living in long-term care. Journal of the American Medical Directors Association. 2017;18(11):941-947. DOI: 10.1016/j.jamda.2017.05.003
  48. 48. Keller HH, Lengyel C, Carrier N, Slaughter SE, Morrison J, Duncan AM, et al. Prevalence of inadequate micronutrient intakes of Canadian long-term care residents. The British Journal of Nutrition. 2018;119(9):1047-1056. DOI: 10.1017/S0007114518000107
  49. 49. Maeda K, Ishida Y, Nonogaki T, Shimizu A, Yamanaka Y, Matsuyama R, et al. Burden of premorbid consumption of texture modified diets in daily life on nutritional status and outcomes of hospitalization. The Journal of Nutrition, Health & Aging. 2019;23(10):973-978. DOI: 10.1007/s12603-019-1237-3
  50. 50. Wu XS, Miles A, Braakhuis A. Nutritional intake and meal composition of patients consuming texture modified diets and thickened fluids: A systematic review and metaanalysis. Healthcare (Basel). 2020;8(4):1-24. DOI: 10.3390/healthcare8040579
  51. 51. Wu S, Morrison-Koechl J, Lengyel C, Carrier N, Awwad S, Keller H. Are therapeutic diets in long-term care affecting resident food intake and meeting their nutritional goals? Canadian Journal of Dietetic Practice and Research. 2020;81(4):186-192. DOI: 10.3148/cjdpr-2020-015
  52. 52. Sorensen J, Fletcher H, Macdonald B, Whittington-Carter L, Nasser R, Gramlich L. Canadian hospital food service practices to prevent malnutrition. Canadian Journal of Dietetic Practice and Research. 2021;82(4):167-175. DOI: 10.3148/cjdpr-2021-013
  53. 53. Strowd L, Kyzima J, Pillsbury D, Valley T, Rubin B. Dysphagia dietary guidelines and the rheology of nutritional feeds and barium test feeds. Dysphagia. 2009;24(1):119-120. DOI: 10.1007/s00455-008-9191-y
  54. 54. Beck AM, Kjaersgaard A, Hansen T, Poulsen I. Systematic review and evidence based recommendations on texture modified foods and thickened liquids for adults (above 17 years) with oropharyngeal dysphagia—An updated clinical guideline. Clinical Nutrition. 2018;37(6):1980-1991. DOI: 10.1016/j.clnu.2017.09.002
  55. 55. Thibault R, Abbasoglu O, Ioannou E, Meija L, Ottens-Oussoren K, Pichard C, et al. ESPEN guideline on hospital nutrition. Clinical Nutrition. 2021;40(12):5684-5709. DOI: 10.1016/j.clnu.2021.09.039
  56. 56. Dziewas R, Michou E, Trapl-Grundschober M, Lal A, Arsava EM, Bath PM, et al. European Stroke Organisation and European Society for Swallowing Disorders guideline for the diagnosis and treatment of post-stroke dysphagia. European Stroke Journal. 2021;6(3):LXXXIX-CXV. DOI: 10.1177/23969873211039721
  57. 57. Volkert D, Beck AM, Cederholm T, Cruz-Jentoft A, Hooper L, Kiesswetter E, et al. ESPEN practical guideline: Clinical nutrition and hydration in geriatrics. Clinical Nutrition. 2022;41(4):958-989. DOI: 10.1016/j.clnu.2022.01.024
  58. 58. Kennewell S, Kokkinakos M. Thick, cheap and easy: Fortifying texture-modified meals with infant cereal. Nutrition and Dietetics. 2007;64(2):112-115. DOI: 10.1111/j.1747-0080.2007.00101.x
  59. 59. Ott A, Senger M, Lötzbeyer T, Gefeller O, Sieber CC, Volkert D. Effects of a texture-modified, enriched, and reshaped diet on dietary intake and body weight of nursing home residents with chewing and/or swallowing problems: An enable study. Journal of Nutrition in Gerontology and Geriatrics. 2019;38(4):361-376. DOI: 10.1080/21551197.2019.1628158
  60. 60. Seemer J, Kiesswetter E, Fleckenstein-Sußmann D, Gloning M, Bader-Mittermaier S, Sieber CC, et al. Effects of an individualised nutritional intervention to tackle malnutrition in nursing homes: A pre-post study. European Geriatric Medicine. 2022;13:741-752. DOI: 10.1007/s41999-021-00597-y
  61. 61. Matta Z, Chambers Iv E, Garcia JM, Helverson JM. Sensory characteristics of beverages prepared with commercial thickeners used for dysphagia diets. Journal of the American Dietetic Association. 2006;106(7):1049-1054. DOI: 10.1016/j.jada.2006.04.022
  62. 62. Goldberg LR, Heiss CJ. The effect of appearance on the palatability of thickened apple juice: A pilot study. Topics in Clinical Nutrition. 2013;28(2):154-162. DOI: 10.1097/TIN.0b013e31828d79df
  63. 63. Ong JJX, Steele CM, Duizer LM. Sensory characteristics of liquids thickened with commercial thickeners to levels specified in the International Dysphagia Diet Standardization Initiative (IDDSI) framework. Food Hydrocolloids. 2018;79:208-217. DOI: 10.1016/j.foodhyd.2017.12.035
  64. 64. Munialo CD, Kontogiorgos V, Euston SR, Nyambayo I. Rheological, tribological and sensory attributes of texture-modified foods for dysphagia patients and the elderly: A review. International Journal of Food Science and Technology. 2020;55(5):1862-1871. DOI: 10.1111/ijfs.14483
  65. 65. Schmidt HDOS, Komeroski MR, Steemburgo T, de Oliveira VR. Influence of thickening agents on rheological properties and sensory attributes of dysphagic diet. Journal of Texture Studies. 2021;52:587-602. DOI: 10.1111/jtxs.12596
  66. 66. Ekberg O, Hamdy S, Woisard V, Wuttge-Hannig A, Ortega P. Social and psychological burden of dysphagia: Its impact on diagnosis and treatment. Dysphagia. 2002;17(2):139-146. DOI: 10.1007/s00455-001-0113-5
  67. 67. Ilhamto N, Anciado K, Keller HH, Duizer LM. In-house pureed food production in long-term care: Perspectives of dietary staff and implications for improvement. Journal of Nutrition in Gerontology and Geriatrics. 2014;33(3):210-228. DOI: 10.1080/21551197.2014.927306
  68. 68. Austbø Holteng LB, Frøiland CT, Corbett A, Testad I. Care staff perspective on use of texture modified food in care home residents with dysphagia and dementia. Annals of Palliative Medicine. 2017;6(4):310-318. DOI: 10.21037/apm.2017.06.24
  69. 69. Garcia JM, Chambers E, Russell EG, Katt A. Modifying food textures: Practices and beliefs of staff involved in nutrition care. American Journal of Speech-Language Pathology. 2018;27(4):1458-1473. DOI: 10.1044/2018_AJSLP-18-0021
  70. 70. McCurtin A, Healy C, Kelly L, Murphy F, Ryan J, Walsh J. Plugging the patient evidence gap: What patients with swallowing disorders post-stroke say about thickened liquids. International Journal of Language & Communication Disorders. 2018;53(1):30-39. DOI: 10.1111/1460-6984.12324
  71. 71. Steele SJ, Ennis SL, Dobler CC. Treatment burden associated with the intake of thickened fluids. Breathe. 2021;17(1):1-6. DOI: 10.1183/20734735.0003-2021
  72. 72. Germain I, Dufresne T, Gray-Donald K. A novel dysphagia diet improves the nutrient intake of institutionalized elders. Journal of the American Dietetic Association. 2006;106(10):1614-1623. DOI: 10.1016/j.jada.2006.07.008
  73. 73. Côté C, Payette H, Gagnon C. Prévenir la dénutrition des personnes âgées dysphagiques institutionnalisées avec une alimentation à textures adaptées: essai clinique randomisé. Canadian Journal of Dietetic Practice and Research. 2017;78(1):45-49. DOI: 10.3148/cjdpr-2016-031
  74. 74. Reyes-Torres CA, Castillo-Martínez L, Reyes-Guerrero R, Ramos-Vázquez AG, Zavala-Solares M, Cassis-Nosthas L, et al. Design and implementation of modified-texture diet in older adults with oropharyngeal dysphagia: A randomized controlled trial. European Journal of Clinical Nutrition. 2019;73(7):989-996. DOI: 10.1038/s41430-019-0389-x
  75. 75. Schoeller DA, Westerterp-Plantenga MS. Advances in the Assessment of Dietary Intake. United States: CRC Press; 2017. DOI: 10.1201/9781315152288
  76. 76. Rondanelli M, Faliva MA, Peroni G, Perna S, Gasparri C, Fazia T, et al. A favorable effect on nutritional status of 12-week tailored texture-modified sous-vide cooking meals in institutionalized elderly women with oropharyngeal dysphagia: An intervention study. Minerva Endocrinology. 2021;46(2):202-213. DOI: 10.23736/S2724-6507.20.03232-0
  77. 77. Comstock EM, St Pierre RG, Mackiernan YD. Measuring individual plate waste in school lunches. Visual estimation and children's ratings vs. actual weighing of plate waste. Journal of the American Dietetic Association. 1981;79(3):290-296
  78. 78. Hawkins KR, Apolzan JW, Myers CA, Martin CK. The assessment of food intake with digital photography. In: Advances in the Assessment of Dietary Intake. United States: CRC Press; 2017. pp. 85-112. DOI: 10.1201/9781315152288
  79. 79. Williamson DA, Allen HR, Martin PD, Alfonso AJ, Gerald B, Hunt A. Comparison of digital photography to weighed and visual estimation of portion sizes. Journal of the American Dietetic Association. 2003;103(9):1139-1145. DOI: 10.1016/S0002-8223(03)00974-X
  80. 80. Martin CK, Han H, Coulon SM, Allen HR, Champagne CM, Anton SD. A novel method to remotely measure food intake of free-living individuals in real time: The remote food photography method. The British Journal of Nutrition. 2009;101(3):446-456. DOI: 10.1017/S0007114508027438
  81. 81. Keller HH, Chambers LW, Fergusson DA, Niezgoda H, Parent M, Caissie D, et al. A mix of bulk and ready-to-use modified-texture food: Impact on older adults requiring dysphagic food. Canadian Journal on Aging. 2012;31(3):335-348. DOI: 10.1017/S0714980812000268
  82. 82. Kawasaki Y, Kojima Y, Akamatsu R. Measuring patient dietary intake using visual estimation methods in Japanese hospitals: A qualitative study. Topics in Clinical Nutrition. 2016;31(4):335-345. DOI: 10.1097/TIN.0000000000000084
  83. 83. Kawasaki Y, Kojima Y, Akamatsu R. Barriers to accurately measuring patients’ dietary intake in hospitals using the visual estimation method: A qualitative study. International Journal of Health Care Quality Assurance. 2016;29(8):835-845. DOI: 10.1108/IJHCQA-04-2016-0042
  84. 84. Bayne D, Barewal R, Shune SE. Sensory-enhanced, fortified snacks for improved nutritional intake among nursing home residents. Journal of Nutrition in Gerontology and Geriatrics. 2022;41(1):92-101. DOI: 10.1080/21551197.2022.2025971
  85. 85. Essat M, Archer R, Williams I, Zarotti N, Coates E, Clowes M, et al. Interventions to promote oral nutritional behaviours in people living with neurodegenerative disorders of the motor system: A systematic review. Clinical Nutrition. 2020;39(8):2547-2556. DOI: 10.1016/j.clnu.2019.11.015
  86. 86. Wu XS, Miles A, Braakhuis AJ. Texture-modified diets, nutritional status and mealtime satisfaction: A systematic review. Healthcare (Basel). 2021;9(6):1-19. DOI: 10.3390/healthcare9060624
  87. 87. Shimizu A, Momosaki R, Kayashita J, Fujishima I. Impact of multiple texture-modified diets on Oral intake and nutritional status in older patients with pneumonia: A retrospective cohort study. Dysphagia. 2020;35(4):574-582. DOI: 10.1007/s00455-019-10063-4
  88. 88. Razalli NH, Cheah CF, Mohammad NMA, Manaf ZA. Plate waste study among hospitalised patients receiving texture-modified diet. Nutrition Research and Practice. 2021;15(5):655-671. DOI: 10.4162/nrp.2021.15.5.655
  89. 89. Endo A, Watanabe Y, Matsushita T, Okada K, Ohara Y, Iwasaki M, et al. Association between weight loss and food form in older individuals residing in long-term care facilities: 1-year multicenter longitudinal study. International Journal of Environmental Research and Public Health. 2021;18(20):1-10. DOI: 10.3390/ijerph182010776
  90. 90. Namasivayam-Macdonald AM, Steele CM, Carrier N, Lengyel C, Keller HH. The relationship between texture-modified diets, mealtime duration, and dysphagia risk in long-term care. Canadian Journal of Dietetic Practice and Research. 2019;80(3):122-126. DOI: 10.3148/cjdpr-2019-004
  91. 91. Steele CM, Molfenter SM, Bailey GL, Polacco RC, Waito AA, Zoratto DCBH, et al. Exploration of the utility of a brief swallow screening protocol with comparison to concurrent videofluoroscopy. Canadian Journal of Speech-Language Pathology & Audiology. 2011;35(3):228-242. DOI: 10.1007/s00455-010-9312-2
  92. 92. Swan K, Cordier R, Brown T, Speyer R. Psychometric properties of visuoperceptual measures of videofluoroscopic and fibre-endoscopic evaluations of swallowing: A systematic review. Dysphagia. 2019;34(1):2-33. DOI: 10.1007/s00455-018-9918-3
  93. 93. Swan K, Cordier R, Brown T, Speyer R. Visuoperceptual analysis of the videofluoroscopic study of swallowing: An international Delphi study. Dysphagia. 2021;36(4):595-613. DOI: 10.1007/s00455-020-10174-3
  94. 94. Edwards A, Froude E, Sharpe G, Carding P. Training for videofluoroscopic swallowing analysis: A systematic review. International Journal of Speech-Language Pathology. 2021;23(5):529-539. DOI: 10.1080/17549507.2020.1861327
  95. 95. Speyer R, Cordier R, Sutt AL, Remijn L, Heijnen BJ, Balaguer M, et al. Behavioural interventions in people with oropharyngeal dysphagia: A systematic review and meta-analysis of randomised clinical trials. Journal of Clinical Medicine. 2022;11(3):1-31. DOI: 10.3390/jcm11030685
  96. 96. Speyer R, Cordier R, Farneti D, Nascimento W, Pilz W, Verin E, et al. White paper by the European Society for Swallowing Disorders: Screening and non-instrumental assessment for dysphagia in adults. Dysphagia. 2022;37(2):333-349. DOI: 10.1007/s00455-021-10283-7
  97. 97. Audag N, Goubau C, Toussaint M, Reychler G. Screening and evaluation tools of dysphagia in adults with neuromuscular diseases: A systematic review. Therapeutic Advances in Chronic Disease. 2019;10:1-15. DOI: 10.1177/2040622318821622
  98. 98. Himashree P, Sengar AS, Sunil CK. Food thickening agents: Sources, chemistry, properties and applications—A review. International Journal of Gastronomy and Food Science. 2022;27:1-13. DOI: 10.1016/j.ijgfs.2022.100468
  99. 99. Bravo-José P, Sáez-Lleó C, Moreno-Guillamont E. Combining liquid oral drugs with thickener: Compatibility and changes in viscosity. Dysphagia. 2021. Epub ahead of print. DOI: 10.1007/s00455-021-10348-7
  100. 100. O'Neil KH, Purdy M, Falk J, Gallo L. The dysphagia outcome and severity scale. Dysphagia. 1999;14(3):139-145. DOI: 10.1007/PL00009595
  101. 101. Crary MA, Carnaby Mann GD, Groher ME. Initial psychometric assessment of a functional oral intake scale for dysphagia in stroke patients. Archives of Physical Medicine and Rehabilitation. 2005;86(8):1516-1520. DOI: 10.1016/j.apmr.2004.11.049
  102. 102. Belafsky PC, Mouadeb DA, Rees CJ, Pryor JC, Postma GN, Allen J, et al. Validity and reliability of the eating assessment tool (EAT-10). The Annals of Otology, Rhinology, and Laryngology. 2008;117(12):919-924. DOI: 10.1177/000348940811701210
  103. 103. Kunieda K, Ohno T, Fujishima I, Hojo K, Morita T. Reliability and validity of a tool to measure the severity of dysphagia: The food intake LEVEL scale. Journal of Pain and Symptom Management. 2013;46(2):201-206. DOI: 10.1016/j.jpainsymman.2012.07.020
  104. 104. Clavé P, De Kraa M, Arreola V, Girvent M, Farré R, Palomera E, et al. The effect of bolus viscosity on swallowing function in neurogenic dysphagia. Alimentary Pharmacology & Therapeutics. 2006;24(9):1385-1394. DOI: 10.1111/j.1365-2036.2006.03118.x
  105. 105. Ninfa A, Pizzorni N, Eplite A, Moltisanti C, Schindler A. Validation of the Italian version of the functional oral intake scale (FOIS-It) against Fiberoptic endoscopic evaluation of swallowing and nutritional status. Dysphagia. 2022;37(1):137-147. DOI: 10.1007/s00455-021-10257-9
  106. 106. Mortensen J, Pedersen AR, Nielsen JF, Kothari M. Construct and content validity of the functional oral intake scale; analyses from a cohort of patients with acquired brain injury. Brain Injury. 2020;34(9):1257-1263. DOI: 10.1080/02699052.2020.1800094
  107. 107. Chen HJ, Chen JL, Chen CY, Lee M, Chang WH, Huang TT. Effect of an oral health programme on oral health, oral intake, and nutrition in patients with stroke and dysphagia in Taiwan: A randomised controlled trial. International Journal of Environmental Research and Public Health. 2019;16(12):1-12. DOI: 10.3390/ijerph16122228
  108. 108. Hey C, Lange BP, Eberle S, Zaretsky Y, Sader R, Stover T, et al. Water swallow screening test for patients after surgery for head and neck cancer: Early identification of dysphagia, aspiration and limitations of oral intake. Dysphagia. 2014;29(3):405-406. DOI: 10.1007/s00455-014-9536-7
  109. 109. Pinto AR, Cola PC, de Carvalho LR, Motonaga SM, da Silva RG. Oral intake and severity scale in neurogenic oropharyngeal dysphagia. Reviews in the Neurosciences. 2013;21(4):531-536. DOI: 10.4181/RNC.2013.21.798.6p
  110. 110. Vucea V, Keller HH, Morrison JM, Duizer LM, Duncan AM, Steele CM. Prevalence and characteristics associated with modified texture food use in long term care: An analysis of making the most of mealtimes (M3) project. Canadian Journal of Dietetic Practice and Research. 2019;80(3):104-110. DOI: 10.3148/cjdpr-2018-045
  111. 111. Seemer J, Kiesswetter E, Blawert A, Fleckenstein D, Gloning M, Bader-Mittermaier S, et al. An individualised nutritional intervention concept for nursing home residents with or at risk of malnutrition: An enable study. Geriatrics (Switzerland). 2021;6(1):1-12. DOI: 10.3390/geriatrics6010002
  112. 112. Melgaard D, Westergren A, Skrubbeltrang C, Smithard D. Interventions for nursing home residents with dysphagia—A scoping review. Geriatrics (Switzerland). 2021;6(2):1-16. DOI: 10.3390/geriatrics6020055
  113. 113. Bruno C, Collier A, Holyday M, Lambert K. Interventions to improve hydration in older adults: A systematic review and meta-analysis. Nutrients. 2021;13(10):1-20. DOI: 10.3390/nu13103640
  114. 114. Huppertz VAL, van Wijk N, Baijens LWJ, de Groot LCPGM, Halfens RJG, Schols JMGA, et al. Design of the DYNAMO study: A multi-center randomized controlled trial to investigate the effect of pre-thickened oral nutritional supplements in nursing home residents with dysphagia and malnutrition (risk). BMC Geriatrics. 2020;20(1):1-10. DOI: 10.1186/s12877-020-01947-4
  115. 115. Faccio AA, Mattos CHPDS, Santos EASD, Neto NRM, Moreira RP, Batella LT, et al. Oral nutritional supplementation in cancer patients who were receiving chemo/chemoradiation therapy: A multicenter, Randomized Phase II Study. Nutrition and Cancer. 2021;73(3):442-449. DOI: 10.1080/01635581.2020.1758170
  116. 116. Wu XS, Yousif L, Miles A, Braakhuis A. A comparison of dietary intake and nutritional status between aged care residents consuming texture modified diets with and without oral nutritional supplements. Nutrients. 2022;14(3):1-13. DOI: 10.3390/nu14030669
  117. 117. Shune S, Barewal R. Redefining the value of snacks for nursing home residents: Bridging psychosocial and nutritional needs. Geriatric Nursing. 2022;44:39-47. DOI: 10.1016/j.gerinurse.2021.12.022
  118. 118. Johnstone AM, Stephen S. Chapter 8—Energy balance: Impact of physiology and psychology on food choice and eating behavior. In: Marriott BP, Birt DF, Stallings VA, Yates AA, editors. Present Knowledge in Nutrition 8th ed. London: Academic Press: 2020. pp. 143-158. DOI: 10.1016/ B978-0-12-818460-8.00008-3
  119. 119. Donini LM. Chapter 2—Control of food intake in aging. In: Raats MM, de Groot LCPGM, van Asselt D, editors. Food for the Aging Population. 2nd ed. Woodhead Publishing; 2017. pp. 25-55. DOI: 10.1016/B978-0-08-100348-0.00002-0
  120. 120. Côté C, Giroux A, Villeneuve-Rhéaume A, Gagnon C, Germain I. Is iddsi an evidence-based framework? A relevant question for the frail older population. Geriatrics (Switzerland). 2020;5(4):1-16. DOI: 10.3390/geriatrics5040082
  121. 121. Cichero JA, Altman KW. Definition, prevalence and burden of oropharyngeal dysphagia: A serious problem among older adults worldwide and the impact on prognosis and hospital resources. Nestle Nutrition Institute Workshop Series. 2012;72:1-11. DOI: 10.1159/000339974
  122. 122. Maslow AH. A theory of human motivation. Psychological Review. 1943;50(4):370-396. DOI: 10.1037/h0054346
  123. 123. Potts R. Introduction to Human Evolution. Smithsonian Institute; 2022 [Website]. Available from:
  124. 124. Ledogar JA, Dechow PC, Wang Q, Gharpure PH, Gordon AD, Baab KL, et al. Human feeding biomechanics: Performance, variation, and functional constraints. PeerJ. 2016;2016(7):1-47. DOI: 10.7717/peerj.2242
  125. 125. Le Magnen J. Hunger. In: Problems in the Behavioural Sciences. United States: Cambridge University Press; 1985
  126. 126. Spence C. The tongue map and the spatial modulation of taste perception. Current Opinion in Food Science. 2022;5:598-610. DOI: 10.1016/j.crfs.2022.02.004
  127. 127. Ji M, Su X, Su X, Chen Y, Huang W, Zhang J, et al. Identification of novel compounds for human bitter taste receptors. Chemical Biology & Drug Design. 2014;84(1):63-74. DOI: 10.1111/cbdd.12293
  128. 128. McMullen MK. Neural transmission from oropharyngeal bitter receptors to the medulla is partially or completely labelled-line. Natural Product Communications. 2016;11(8):1201-1204. DOI: 10.1177/1934578x1601100841
  129. 129. Simmen B, Hladik A, Ramasiarisoa PL, Iaconelli S, Hladik CM. Taste discrimination in lemurs and other primates, and the relationships to distribution of plant Allelochemicals in different habitats of Madagascar. In: Publishers KAP, editor. New Directions in Lemur Studies. New York; 1999. pp. 201-209
  130. 130. Lee H, MacPherson LJ, Parada CA, Zuker CS, Ryba NJP. Rewiring the taste system. Nature. 2017;548(7667):330-333. DOI: 10.1038/nature23299
  131. 131. Spielman AI, Brand JG. Wiring taste receptor cells to the central gustatory system. Oral Diseases. 2018;24(8):1388-1389. DOI: 10.1111/odi.12833
  132. 132. Spector AC, Blonde G, Garcea M, Jiang E. Rewiring the gustatory system: Specificity between nerve and taste bud field is critical for normal salt discrimination. Brain Research. 2010;1310:46-57. DOI: 10.1016/j.brainres.2009.11.021
  133. 133. Peng Y, Gillis-Smith S, Jin H, Tränkner D, Ryba NJP, Zuker CS. Sweet and bitter taste in the brain of awake behaving animals. Nature. 2015;527(7579):512-515. DOI: 10.1038/nature15763
  134. 134. Cattaneo C, Gargari G, Koirala R, Laureati M, Riso P, Guglielmetti S, et al. New insights into the relationship between taste perception and oral microbiota composition. Scientific Reports. 2019;9(1):1-8. DOI: 10.1038/s41598-019-40374-3
  135. 135. Cattaneo C, Riso P, Laureati M, Gargari G, Pagliarini E. Exploring associations between interindividual differences in taste perception, oral microbiota composition, and reported food intake. Nutrients. 2019;11(5):1-17. DOI: 10.3390/nu11051167
  136. 136. Esberg A, Haworth S, Hasslöf P, Holgerson PL, Johansson I. Oral microbiota profile associates with sugar intake and taste preference genes. Nutrients. 2020;12(3):1-19. DOI: 10.3390/nu12030681
  137. 137. Fluitman KS, van den Broek TJ, Nieuwdorp M, Visser M, Ijzerman RG, Keijser BJF. Associations of the oral microbiota and Candida with taste, smell, appetite and undernutrition in older adults. Scientific Reports. 2021;11(1):1-11. DOI: 10.1038/s41598-021-02558-8
  138. 138. Kaur K, Sculley D, Veysey M, Lucock M, Wallace J, Beckett EL. Bitter and sweet taste perception: Relationships to self-reported oral hygiene habits and oral health status in a survey of Australian adults. BMC Oral Health. 2021;21(1):1-11. DOI: 10.1186/s12903-021-01910-8
  139. 139. Mozhdehi FJ, Abeywickrema S, Bremer PJ, Peng M. Comparing taste detection thresholds across individuals following vegan, vegetarian, or omnivore diets. Foods. 2021;10(11):1-11. DOI: 10.3390/foods10112704
  140. 140. Sedghi L, DiMassa V, Harrington A, Lynch SV, Kapila YL. The oral microbiome: Role of key organisms and complex networks in oral health and disease. Periodontology 2000. 2021;87(1):107-131. DOI: 10.1111/prd.12393
  141. 141. Koc H, Vinyard CJ, Essick GK, Foegeding EA. Food oral processing: Conversion of food structure to textural perception. Annual Review of Food Science and Technology. 2013;4(1):237-266. DOI: 10.1146/annurev-food-030212-182637
  142. 142. Foster KD, Grigor JM, Cheong JN, Yoo MJ, Bronlund JE, Morgenstern MP. The role of oral processing in dynamic sensory perception. Journal of Food Science. 2011;76(2):R49-R61. DOI: 10.1111/j.1750-3841.2010.02029.x
  143. 143. González R, Montoya I, Cárcel J. The use of electromyography on food texture assessment. Food Science and Technology International. 2001;7(6):461-471. DOI: 10.1106/NRHT-L39D-HY1Y-8RGB
  144. 144. Taniguchi H, Tsukada T, Ootaki S, Yamada Y, Inoue M. Correspondence between food consistency and suprahyoid muscle activity, tongue pressure, and bolus transit times during the oropharyngeal phase of swallowing. Journal of Applied Physiology. 2008;105(3):791-799. DOI: 10.1152/japplphysiol.90485.2008
  145. 145. Funami T, Ishihara S, Kohyama K. Use of electromyography in measuring food texture. Food Texture Design and Optimization. Wiley Blackwell; 2014:283-307. 10.1002/9781118765616.ch11
  146. 146. Tournier C, Grass M, Septier C, Bertrand D, Salles C. The impact of mastication, salivation and food bolus formation on salt release during bread consumption. Food & Function. 2014;5(11):2969-2980. DOI: 10.1039/c4fo00446a
  147. 147. Mori K, Manda Y, Kitagawa K, Nagatsuka H, Furutera H, Kodama N, et al. Coordination of surface electromyography activity in the posterior tongue region during mastication of differently textured foods. Journal of Oral Rehabilitation. 2021;48(4):403-410. DOI: 10.1111/joor.13135
  148. 148. Matsuo K, Kito N, Ogawa K, Izumi A, Masuda Y. Effects of textured foods on masticatory muscle activity in older adults with oral hypofunction. Journal of Oral Rehabilitation. 2020;47(2):180-186. DOI: 10.1111/joor.12901
  149. 149. Steele CM. The blind scientists and the elephant of swallowing: A review of instrumental perspectives on swallowing physiology. Journal of Texture Studies. 2015;46(3):122-137. DOI: 10.1111/jtxs.12101
  150. 150. Guo Q. Understanding the oral processing of solid foods: Insights from food structure. Comprehensive Reviews in Food Science and Food Safety. 2021;20(3):2941-2967. DOI: 10.1111/1541-4337.12745
  151. 151. Matsuo K, Fujishima I. Textural changes by mastication and proper food texture for patients with oropharyngeal dysphagia. Nutrients. 2020;12(6):1-15. DOI: 10.3390/nu12061613
  152. 152. Drake MA. Sensory evaluation. In: McSweeney PLH, McNamara JP, editors. Encyclopedia of Dairy Sciences. 3rd ed. Oxford: Academic Press; 2022. pp. 572-576. DOI: 10.1016/B978-0-12-818766-1.00151-3
  153. 153. Stone H, Bleibaum RN, Thomas HA editors. Sensory Evaluation Practices. 5th ed. London: Academic Press; 2020
  154. 154. Meiselman HL, Schutz HG. History of food acceptance research in the US Army. Appetite. 2003:40(3):199-216. DOI: 10.1016/S0195-6663(03)00007-2
  155. 155. Bourne MC. Chapter 1—Texture, viscosity, and food. In: Bourne MC, editor. Food Texture and Viscosity. San Diego: Academic Press; 2012:1-32. DOI: 10.1016/B978-0-12-119060-6.50006-X
  156. 156. Stone H, Bleibaum RN, Thomas HA. Chapter 1—Introduction to sensory evaluation. In: Stone H, Bleibaum RN, Thomas HA, editors. Sensory Evaluation Practices. 4th ed. San Diego: Academic Press; 2012:1-21. DOI: 10.1016/B978-0-12-382086-0.00001-7
  157. 157. Peryam DR, Pilgrim FJ. Hedonic scale method of measuring food preferences. Food Technology. 1957;11(Suppl):9-14
  158. 158. Peryam DR, Girardot NJGSHS. Advanced Taste-Test Method. 1998
  159. 159. Wichchukit S, O'Mahony M. The 9-point hedonic and unstructured line hedonic scales: An alternative analysis with more relevant effect sizes for preference. Food Quality and Preference. 2022;99:104575. DOI: 10.1016/j.foodqual.2022.104575
  160. 160. Mongi RJ, Gomezulu AD. Descriptive Sensory Analysis, Consumer Preference, and Conjoint Analysis of Beef Sausages Prepared from a Pigeon Pea Protein Binder. SSRN (Social Science Research Network). 2022. Under Review. DOI: 10.2139/ssrn.4047097
  161. 161. Gupta MK, Gonzalez Viejo C, Fuentes S, Torrico DD, Saturno PC, Gras SL, et al. Digital technologies to assess yoghurt quality traits and consumers acceptability. 2022
  162. 162. Vucea V, Keller HH, Morrison JM, Duncan AM, Duizer LM, Carrier N, et al. Nutritional quality of regular and pureed menus in Canadian long term care homes: An analysis of the Making the Most of Mealtimes (M3) project. BMC Nutrition. 2017;3(1):1-11. DOI: 10.1186/s40795-017-0198-3
  163. 163. Cichero JAY, Lam P, Steele CM, Hanson B, Chen J, Dantas RO, et al. Development of international terminology and definitions for texture-modified foods and thickened fluids used in dysphagia management: The IDDSI framework. Dysphagia. 2017;32(2):293-314. DOI: 10.1007/s00455-016-9758-y
  164. 164. Stahlman LB, Garcia JM, Chambers E, Smit AB, Hoag L, Chambers DH. Perceptual ratings for pureed and molded peaches for individuals with and without impaired swallowing. Dysphagia. 2001;16(4):254-262. DOI: 10.1007/s00455-001-0084-6
  165. 165. Sharma M, Kristo E, Corredig M, Duizer L. Effect of hydrocolloid type on texture of pureed carrots: Rheological and sensory measures. Food Hydrocolloids. 2017;63:478-487. DOI: 10.1016/j.foodhyd.2016.09.040
  166. 166. Rothenberg E, Ekman S, Bülow M, Möller K, Svantesson J, Wendin K. Texture-modified meat and carrot products for elderly people with dysphagia: Preference in relation to health and oral status. Scandinavian Journal of Food and Nutrition. 2007;51(4):141-147. DOI: 10.1080/17482970701760675
  167. 167. Wendin K, Ekman S, Bülow M, Ekberg O, Johansson D, Rothenberg E, et al. Objective and quantitative definitions of modified food textures based on sensory and rheological methodology. Food & Nutrition Research. 2010;54:1-11. DOI: 10.3402/fnr.v54i0.5134
  168. 168. Martínez O, Vicente MS, De Vega MC, Salmerón J. Sensory perception and flow properties of dysphagia thickening formulas with different composition. Food Hydrocolloids. 2019;90:508-514. DOI: 10.1016/j.foodhyd.2018.12.045
  169. 169. Ross AIV, Tyler P, Borgognone MG, Eriksen BM. Relationships between shear rheology and sensory attributes of hydrocolloid-thickened fluids designed to compensate for impairments in oral manipulation and swallowing. Journal of Food Engineering. 2019;263:123-131. DOI: 10.1016/j.jfoodeng.2019.05.040
  170. 170. Cichero JAY, Steele C, Duivestein J, Clavé P, Chen J, Kayashita J, et al. The need for international terminology and definitions for texture-modified foods and thickened liquids used in dysphagia management: Foundations of a global initiative. Current Physical Medicine and Rehabilitation Reports. 2013;1(4):280-291. DOI: 10.1007/s40141-013-0024-z
  171. 171. Felt P. The National Dysphagia Diet Project: The science and practice. Nutrition in Clinical Practice. 1999;14(5):S60-SS5. DOI: 10.1177/088453369901400513
  172. 172. Mills RH. Rheology overview: Control of liquid viscosities in dysphagia management. 1999;14(5S):S52-SS6. DOI: 10.1177/0884533699014005S11
  173. 173. Tymchuck D. Textural property considerations of food for dysphagia. 1999;14(5S):S57-SS9. DOI: 10.1177/0884533699014005S12
  174. 174. Côté C, Germain I, Dufresne T, Gagnon C. Comparison of two methods to categorize thickened liquids for dysphagia management in a clinical care setting context: The Bostwick consistometer and the IDDSI flow test. Are we talking about the same concept? Journal of Texture Studies. 2019;50(2):95-103. DOI: 10.1111/jtxs.12377
  175. 175. Sherman P. Food Texture and Rheology. London: Academic Press; 1979
  176. 176. Gallegos C, Turcanu M, Assegehegn G, Brito-de la Fuente E. Rheological issues on oropharyngeal dysphagia. Dysphagia. 2021:1-28. DOI: 10.1007/s00455-021-10337-w
  177. 177. Raheem D, Carrascosa C, Ramos F, Saraiva A, Raposo A. Texture-modified food for dysphagic patients: A comprehensive review. International Journal of Environmental Research and Public Health. 2021;18(10):1-24. DOI: 10.3390/ijerph18105125
  178. 178. Szczesniak AS. Classification of textural characteristics. Journal of Food Science. 1963;28(4):385-389. DOI: 10.1111/j.1365-2621.1963.tb00215.x
  179. 179. Szczesniak AS, Brandt MA, Friedman HH. Development of standard rating scales for mechanical parameters of texture and correlation between the objective and the sensory methods of texture evaluation. Journal of Food Science. 1963;28(4):397-403. DOI: 10.1111/j.1365-2621.1963.tb00217.x
  180. 180. van der Stelt AJ, Mehring P, Corbier C, van Eijnatten EJM, Withers C. A “mouthfeel wheel” terminology for communicating the mouthfeel attributes of medical nutrition products (MNP). Food Quality and Preference. 2020;80:1-11. DOI: 10.1016/j.foodqual.2019.103822
  181. 181. Deeks J, Verreault MF, Cheung W. Canadian nutrient file (CNF): Update on Canadian food composition activities. Journal of Food Composition and Analysis. 2017;64:43-47. DOI: 10.1016/j.jfca.2017.04.009
  182. 182. Bodner-Montville J, Ahuja JKC, Ingwersen LA, Haggerty ES, Enns CW, Perloff BP. USDA Food and Nutrient Database for Dietary Studies: Released on the web. Journal of Food Composition and Analysis. 2006;19(Suppl):S100-S1S7. DOI: 10.1016/j.jfca.2006.02.002
  183. 183. Charrondiere UR, Vignat J, Møller A, Ireland J, Becker W, Church S, et al. The European Nutrient Database (ENDB) for nutritional epidemiology. Journal of Food Composition and Analysis. 2002;15(4):435-451. DOI: 10.1006/jfca.2002.1089
  184. 184. Watanabe T. Food composition tables of Japan and the nutrient table/database. Journal of Nutritional Science and Vitaminology (Tokyo). 2015;61(Suppl):S25-S27. DOI: 10.3177/jnsv.61.S25

Written By

Isabelle Germain

Submitted: 26 April 2022 Reviewed: 04 May 2022 Published: 05 July 2022