MIND Diet

Abstract

Age-associated changes in the brain, injuries such as stroke or traumatic brain injury, mood disorders like depression, substance use disorder, or addiction, and diseases such as Alzheimer’s disease will affect brain health. Some factors affecting brain health cannot be changed, but many lifestyle changes have the potential to make a difference. Dietary patterns have been associated with protective relations to cognitive decline and incident dementia in epidemiological studies. An amalgam of the Mediterranean-DASH diets, called the MIND diet, emphasizes the dietary components and servings linked to neuroprotection and dementia prevention. Analogous to the Mediterranean and DASH diets, the MIND diet score highlights natural plant-based foods and limited intakes of animal foods. The diet uniquely stipulates consumption of green leafy vegetables, other vegetables, berries, nuts, whole grains, olive oil, fish, beans, poultry, and wine, but does not specify high fruit consumption, dairy products, red meat, and fried foods. The MIND diet score was related to a slower rate of cognitive decline, equivalent to 7.5 years of younger age. It was evident that the MIND diet reduces a person’s risk of developing Alzheimer’s disease dementia and also the diet comprises a variety of nutrient sources in the right proportions.

1. Introduction

Cognitive decline is an alarming public health concern. Intellectual debility related to aging is a staid health issue, which increases the prevalence of neurodegenerative diseases as people are active longer and the proportion of aged persons globally remains increasing rapidly [1]. World Health Organization (WHO) reported that dementia affects an estimated 50 million people, and this prevalence is projected to rise over 130 million by 2050 [2]. Further epidemiological studies advocate an adverse interaction of aging and obesity with cognitive dysfunction [3, 4]. There are additional adverse implications for cognition health which are assessed as 30% prevalent among the overweight and obese adult population [5, 6]. The strong predictors of functional disability and dependence are dementia and cognitive impairment, which leads to major socioeconomic burden [7].

The usual part of the aging process is cognitive decline, but the rate of decline may differ depending on the variations in genetic and lifestyle-associated factors [8]. Elderly people develop these protein deposits, known as amyloid plaques and tangles. Plaques and tangles are a pathology found in the brain that builds up in between nerve cells and typically interfere with thinking and problem-solving skills. Aging acquires a toll on the body and mind. For instance, the tissue of aging human brains sometimes develops abnormal clumps of proteins, which are the hallmark of Alzheimer’s disease. Currently, the brain can be protected from these effects by a healthy diet.

A healthy diet has the potential in preserving the brain and maintaining cognitive health. The potential of modifiable lifestyle factors is important as there are no effective pharmacological agents identified for the improvement of cognition or delay of the progression of cognitive decline [9]. Diet is a key lifestyle risk factor. Personalized nutrients in foods have been contradictorily related to cognitive function, which includes some vitamins, carotenoids, long-chain n-3 polyunsaturated fatty acids (PUFAs) in kinds of seafood, whole grainy foods rich in polyphenols, nuts, olive oil, coffee, fruits, and vegetables [10, 11, 12].

2. An overview of MIND diet

As food is consumed as part of a dietary pattern, it is important to consider the interactions and associations of whole dietary approaches. Predominantly, three dietary patterns are put forward to have a beneficial impact on cognitive function. They are the Mediterranean diet (MedDiet), the Dietary Approaches to Stop Hypertension (DASH), and the MedDiet-DASH Intervention for Neurodegenerative Delay (MIND). At present, the MedDiet and DASH are advocated for their cardiovascular benefits [13] but also advisable to promote cognition in them and because of the association between the risk factors of vascular problems with dementia [14]. A relationship between adherence to MedDiet and cognitive function was proved by several epidemiological studies and clinical trials [15, 16], and the World Health Organization (WHO) has included this dietary pattern in their guidelines to reduce the risk of cognitive decline and dementia; on the other hand, it is conditionally considered the potency of the recommendation [2]. Even though it has been less comprehensively investigated in association with cognition and other cardiometabolic health outcomes, an amalgam of the MedDiet and DASH diet, the MIND diet, is also being promoted for brain health [17].

The potentially effective preventive strategies are dietary interventions because nutrition is a modifiable factor for intervention in cognitive disorders. The MIND diet aims to lessen dementia and the decline in brain health that is prevalent as people get older. The MIND diet is the combined aspects of two accepted diets, the Mediterranean diet, and the DASH diet. Many researchers consider the Mediterranean and DASH diets as one of the healthiest diets. Studies have proven that they can lower blood pressure and reduce the risk of heart disease, diabetes, and numerous other diseases also. The diet is tailored after the Mediterranean and DASH diets but with modifications based on the most persuasive findings in the area of diet for dementia.

The MIND diet combines the DASH and Mediterranean diets to create a diet aimed at reducing the risk of dementia and the decline in brain health that people often experience as they age. The MIND diet encourages the consumption of all kinds of vegetables, berries, nuts, olive oil, whole grains, fish, beans, poultry, and a moderate amount of wine. To improve cognition, currently, the MIND diet is found to be superior and beneficial when compared to various other plant-based diets including the Mediterranean, Dietary Approaches to Stop Hypertension, Pro-Vegetarian, and Baltic Sea diets. MIND diet adherence is possibly related to an improved cognitive function in elderly people.

3. Potential mechanism of the MIND diet

Several studies proved that there is an impact on biological mechanisms of neurocognitive aging by antioxidant, vitamin, probiotic, plant protein, and unsaturated fatty acid content along with low glycemic index/load components in a regular diet [18]. Promotion of vascular health and neuroprotection by anti-inflammatory mechanisms and reducing oxidative stress, ameliorating glycemic control, and supporting a favorable microbiome possibly lead to enhanced cognitive function [19]. Specifically, the observations with the MedDiet and changes in cognitive function may be related to synergistic or individual associations of specific foods, such as olive oil and nuts, due to associations of these foodstuffs with the above-mentioned mechanisms [20, 21, 22].

The amalgamation of the Mediterranean and the DASH diet pattern is the MIND diet. Researchers substantiated through observational studies that Alzheimer’s disease is prevented or potentially delayed by following these two dietary patterns. Morris et al. [23] in their observational studies found that the risk of developing Alzheimer’s disease was reduced by 53% among people who followed the MIND diet strictly and by 35% reduction who followed moderately [24]. This combination of these two diets will reduce oxidative stress and inflammation in the body, which moderates brain cell damage. The recommended guidelines for the MIND diet focus more on plant-based foods that are marginally processed, limit animal-based foods that are high in saturated fats, and foods with added sugars. Portion control is also recommended but does not emphasize weight loss. The principles of the MIND diet include having 10 food groups and a limit to 5. The diet advises fundamentally to take 3 servings of whole grains, fruits, and vegetables, 1 to 2 servings of beans, poultry, and fish each week, and daily snacks can include nuts and berries every day. The diet highlights mostly choose olive oil as a healthy source of fat for cooking foods. There is no restriction on intake of meats and dairy products, the diet recommends to have sparingly as less than four times a week. As a substitute, the diet recommends protein-packed beans and legumes which are vital for brain health.

4. Role of MIND diet and protocol

The performance of the human brain is based on an interplay between the inherited genotype and external environmental factors, with diet. To maintain brain performance food and nutrition are essential which aid in the prevention and treatment of mental disorders. Various experimental models and epidemiological studies evidenced that the whole composition of the human diet with specific dietary components has an impact on brain function. The role of the MIND diet in 5 key areas of brain function linked to mental health and performance are displayed below (Figure 1).

Figure 1.

Role of the MIND diet.

5. Benefits of the MIND diet

To stick to and get benefited from the MIND diet, include at least three servings of whole grains, a green leafy vegetable with one other vegetable and fruits especially berries daily, snack most days on nuts, have beans every other day, poultry at least twice a week and fish at least once a week. Intake of the designated unhealthy foods, ghee, butter, sweets and pastries, whole fat cheese, and fried or fast food should be restricted. Food groups recommended in the MIND diet are found to boost brain health as it is a rich source of fiber and packed with all necessary nutrients like vitamin E, folate, omega-3 fatty acids, carotenoids, and flavonoids. Research shows that the MIND diet can improve brain health and a lower likelihood of developing conditions like Alzheimer’s disease, dementia, and other forms of age-related cognitive decline. Studies indicate that including certain foods on regular basis and avoiding unhealthy ones will slow brain aging by 7.5 years (Tables 1 and 2).

S. No	Included foods in the MIND diet	Recommendation
1	Green leafy vegetables	one serving daily
2	All other vegetables	2 or more servings per day
3	Berries	2 or more servings per week
4	Nuts	5 or more servings per week
5	Olive oil	2 tablespoons per day
6	Whole grains	3 or more servings per day
7	Fish/seafood	1 or more servings per week
8	Beans	4 or more servings per week
9	Poultry	2 or more servings per week
10	Wine	30 g per day, also can skip it

Table 1.

The MIND Diet—Foods to be included.

*

One serving = 1 cup raw or ½ cup cooked.

Source: Morris MC et al. [24], MIND diet associated with reduced incidence of Alzheimer’s disease. Alzheimer’s & Dementia; 2015.

S. No	Restricted foods in the MIND diet	Recommendation
1	Red Meat & Processed Meat	Not more than 3 servings per week
2	Butter & Stick Margarine	Less than 1 tsp per day
3	Regular Cheese	No more than 2 oz. per week
4	Pastries & Other Sweets	No more than 4 treats per week
5	Fried Foods & Fast Foods	No more than 1 meal per week

Table 2.

The MIND Diet—Foods to be restricted.

*

One serving = 3 to 5 oz.

Source: Morris MC et al. [24], MIND diet associated with reduced incidence of Alzheimer’s disease. Alzheimer’s & Dementia; 2015.

6. Components of MIND diet and its role to health

6.1 Green leafy vegetables

Green leaves like kale, spinach, collards, and broccoli are the sources of brain-healthy nutrients like vitamin K, lutein, folate, and beta carotene. Research recommends that these plant-based foods will slow down cognitive decline. Due to the neuroprotective actions of phylloquinone, lutein, nitrate, folate, α-tocopherol, and kaempferol, the intake of green leafy vegetables 1 serving per day aids to lessen the decline in cognitive abilities with older age. Further, the daily serving of green leafy vegetables in a regular diet is an economic and simple mode to improve and maintain brain health [23]. The nutrients in green leafy vegetables will have independent mechanisms of action that synergistically protect the brain. Serum carotenoid levels were related to less severe periventricular white matter lesions, predominantly in elderly smokers. Lutein reduces phospholipid peroxidation in human erythrocytes, to attenuate oxidative stress, mitochondrial dysfunction, and neuroinflammation. Folate inhibits tau phosphorylation, APP, PS1, and Aβ protein levels which triggers Alzheimer’s disease pathogenesis, to increase methylation potential and DNA methyltransferase activity.

6.2 All other vegetables

Scientific evidence has shown the association between vegetable intake and its polyphenols for the prevention or treatment of diseases. The compounds in vegetables act to improve neuronal plasticity through the protein CREB (Camp Response Element Binding) in the hippocampus, modulating pathways of signaling and transcription factors (ERK/Akt). In the same way, brain-derived neurotrophic factor (BDNF) is involved in the maintenance, survival, growth, and differentiation of neurons. All these effects are produced by an increase in cerebral blood flow, with an upsurge in the blood’s nitric oxide levels and oxygenation [25]. Terpenoids, carotenoids, phenolics, phytosterols, and glucosinolates are the most prominent bioactive compounds existing in vegetables found to be operational in preventing neurodegeneration.

6.3 Berries

Research indicates that flavonoids, the natural plant pigments in berries help to progress memory. Flavonoids in plants have potent antioxidant and anti-inflammatory properties. Stress and inflammation are the factors to contribute cognitive impairment and the regular consumption of flavonoids quantitatively will mitigate the harmful effects. Studies on the positive effects of flavonoids, particularly anthocyanidins, are limited to animal models or very small trials in the elderly but proved that greater consumption of foods with these compounds improved cognitive function. Studies show that regular intake of blueberries and strawberries, which are high in flavonoids, delayed cognitive decline in elderly people by up to 2.5 years [26].

6.4 Nuts

The outstanding sources of protein and healthy fats are the nuts which aid to improve memory as well as good for both the heart and brain. An omega-3 fatty acid called alpha-linolenic acid (ALA) is found to be high in walnuts. There is an association between intake of diets rich in ALA and omega-3 fatty acids to cardiovascular regulation as it lowers blood pressure and makes arteries cleaner. In 2015 a study was done by the University of California, Los Angeles (UCLA) related higher walnut consumption to improved cognitive test scores.

6.5 Vegetable oils

The beneficial effects of the MedDiet on cognitive functions have been attributed to its high MUFA content. Medium-chain triglycerides (MCTs) or medium-chain fatty acids in coconut oil improve cognition in Alzheimer’s patients, also helps to improve insulin resistance, which is an excellent treatment for dementia patients and diabetics. Caprylic acid is the MCT derived from coconut or palm oil helps to improve cognitive function in Alzheimer’s patients. Olive oil is a source of fatty acids and antioxidant-rich food. The best quality form of olive oil is extra-virgin olive oil (EVOO). Regular intake of EVOO is linked with lower mitochondrial oxidative stress, which counteracts age-related cognitive decline. The secoiridoid oleuropein, resp. oleuropein aglycone in olive oil is responsible for its neuroprotective effect. The results of in vitro and in vivo studies specify that the regular intake of EVOO is associated with enhanced cognitive functions, which proves that olive oil has a neuroprotective effect and positively prevents the development of dementia and Alzheimer’s disease [27].

6.6 Whole grains

Whole grains are the richest source of protein, fiber, B vitamins, antioxidants, and trace minerals (iron, zinc, copper, and magnesium). A regular diet rich in whole grains reduces the risk of heart disease, type 2 diabetes, obesity, and some types of cancer. Naturally, whole grains are rich in amino acids, especially tryptophan, which is vital for serotonin and melatonin production. Serotonin is the “feel-good hormone,” which improves mood, relaxes the brain and body, whereas melatonin helps to establish and maintain stable sleep cycles. The dietary pattern with a higher intake of red meat, processed meat, peas, legumes, fried foods, and a lower intake of whole grains was related to higher inflammatory markers and accelerated cognitive decline in elderly people [28].

6.7 Seafood

Fatty fish like salmon, mackerel, herring, and sardines are abundant sources of omega-3 fatty acids, unsaturated fats that have been connected to lower blood levels of beta-amyloid, the protein responsible for the formation of clumps in the brains of people with Alzheimer’s disease. Fish intake is recommended weekly twice and the best fish varieties to prefer for brain health are salmon, cod, canned light tuna, herring, and Pollack which are also low in mercury. Further, these varieties of fish also contain Vitamin B12, the essential nutrient to maintain nerves and blood vessels and involved in creating DNA. Omega-3 fatty acids are responsible for physiological functions that are interconnected to neurogenesis, neurotransmission, and neuroinflammation. Hence, they play dynamic roles in the development, functioning, and aging of the brain. The dietary deficiencies of omega-3 fatty acids in humans are linked with an increased risk of developing various psychiatric disorders, including depression, bipolar disorder, schizophrenia, dementia, attention-deficit/hyperactivity disorder, and autism [29]. Omega-3 fatty acids, docosahexaenoic acid (DHA), help to improve memory and brain health. The best sources of omega-3 fatty acid, DHA among the seafood, algae, and fatty fish are salmon, bluefin tuna, sardines, and herring.

6.8 Beans

Beans which also include other legumes, such as lentils, soybeans, black beans, chickpeas are another staple food staple good for brain health. High consumption of legumes like three or more servings per week has been related to enhance cognitive performance, with the utmost concentration of folate. Beans are rich in protein, carbohydrates, fiber, B-vitamins and omega fatty acids anti-oxidants, and minerals. Beans digest slowly as it takes 2 to 3 hours and while digesting they provide the brain with a consistent source of glucose. All the bean varieties with kidney and pinto beans are preferred for brain health as they comprise more omega-3 fatty acids. Beans have a remarkably high concentration of certain anti-inflammatory compounds which appears to be neuroprotective [30].

6.9 Poultry

Chicken is a rich source of lean protein and brain-healthy compounds like dietary choline and vitamins B6 and B12. Choline and the B vitamins play vital roles in healthy cognition and provide neuroprotective benefits. Studies evidenced that the intake of poultry enhances mental functions and developments used in working memory among healthy adults and short-term memory among healthy adults who experience stress in daily life [31]. The blend of vitamin B6, B12, and folate plays a key role in the reduction of cognitive decline and age-related memory loss, stroke, Alzheimer’s disease, and depression [32].

6.10 Wine

One component of the Mediterranean diet is the intake of wine, which is associated with the promotion of human mental and heart health and the prevention of diseases. An optimum amount of wine for neuroprotection seems to be up to 30 g of alcohol per day. Moderate wine consumption is related to higher blood levels of omega-3 fatty acids that protect against heart disease, metabolize glucose, decrease cardiometabolic risk, increased levels of heme-oxygenase, prevention of blood clotting and also protect the brain from stroke. The risk of developing dementia and depression was advocated to be reduced by a moderate intake of wine [33]. A wide range of polyphenols present in red wine includes resveratrol, flavanols like quercetin, myricetin, phenolic acids, trihydroxystilbene, flavanols like epicatechin, catechin, procyanidins, and anthocyanins, which are responsible for the color of red wines. It was evidenced in humans from randomized clinical trials that resveratrol is able to improve cerebral blood flow, cerebral vasodilator responsiveness to hypercapnia, some cognitive tests, perceived performances, and the Aβ40 plasma and cerebrospinal fluid level [34].

7. Conclusion

Researches are evident that the DASH diet and the Mediterranean diet improve cognitive function and development [35, 36]. By the support of these studies, the two diets have been combined to construct a hybrid MIND diet which is specifically designed to improve brain health. The MIND diet lays emphasis on the regular intake of leafy green vegetables, other vegetables, berries, legumes, fish, nuts, and whole grains whereas it limits butter, cheese, and red meat consumption. Studies suggested that the MIND diet can slow down age-related cognitive decline and reduce the risk of Alzheimer’s disease [37, 38]. The Dukan and Atkins diets radically cut carbohydrates and fat in favor of protein, while the Palaeolithic diet greatly restricts starch in favor of fat and protein. These nutrient imbalances have beneficial effects only in the short term, especially on weight loss, but there are serious doubts about their long-term results. Whereas in the MIND diet, all the nutrient groups are included and a variety of nutrient sources are recommended in the right proportions, as per international nutritional recommendations. The MIND diet is also found to be a good source of carbohydrates, protein fat, and all other nutrients. Adherence to the MIND diet will improve brain health, and slow down cognitive decline in individuals with Alzheimer’s disease.

Acknowledgments

The infrastructural facilities provided and the support given by the management of PSG College of Arts & Science are duly acknowledged herewith.

Conflict of interest

The author does not have any conflict of interest whatsoever with regard to the content or opinions expressed above.