The mean average demographics obtained from the Anne-Wien elementary school and the alternative site in Fairbanks (Byrd animal facility staff at U Alaska Fairbanks) on the left side. On the right side are the demographics for the Hackett middle School in Albany and the alternative site in Albany, NY (Comprehensive Neuropsychological Services).
One Health is a principle that takes into account the interactions of humans, animals, the surrounding environment, and how they affect each other. In order to examine this concept in an experimental paradigm, the effects and benefits of wild Alaskan blueberries were compared to those from the continental United States (Lower-48 states) in human and animal studies. Blueberries have been hailed as a superfood for years now due to their high antioxidant levels and the positive effects they have on cardiovascular health and overall health and well-being. We hypothesize that although they are both beneficial, wild Alaskan blueberries have a greater positive effect on health and well-being than those from the lower 48. First, teachers and staff at the Anne Wien Elementary School in Fairbanks Alaska were provided with Alaskan and Lower-48 blueberries and asked to log the effects each coded sample had on their mental and physical health compared to a 5-day control period without blueberries. There was a significant stepwise positive effect of respondents reporting higher self-ratings of well-being overall. Alaskan blueberries significantly improved self-ratings of well-being compared to those from Lower-48 blueberries, albeit those blueberries did improve well-being compared to no blueberries. This experiment was replicated at a control site contemporaneously. The following year it was also replicated by participating teachers and staff at William S. Hackett Middle School in Albany, New York, as well as a control site. Further, lab rats, whose diets were supplemented with with Alaskan blueberries, performed better in exploratory and cognitive tests than did rats whose diets were supplemented with Lower-48 blueberries (who, similar to the previous trials, performed better than rats whose diets had not been supplemented at all). These findings suggest that blueberries have an overall positive effect on self-rated wellness in people and cognitive performance in lab rats and that Alaskan blueberries have a particularly greater and more beneficial effect. Whether this is due to greater antioxidant effects associated with higher altitude or fewer endocrine-disrupting contaminants in Alaska compared to the Lower-48 States is unknown and subject to ongoing investigation.
- low density liposaccharides
- high blood pressure
- cognitive decline
Consumption of fruits and vegetables is often correlated with brain and heart health and cancer prevention. One way that fruits and vegetables have beneficial effects on health is through their antioxidant actions. Not all fruits and vegetables are the same in terms of their antioxidant actions. When scientists tested 143 different plants for their antioxidant power: blueberries scored 4669 > cherries were 3747 and prune juice came in at 2036; avocado was at 1922; grapefruit had a power score of 1640, spinach was 1513 and raw broccoli was 1510 and pineapple was a low 385. These results on an ORAC scale compare items among food groups that show relative antioxidant activity. ORAC is a measure of water-soluble antioxidant levels and does not distinguish among those antioxidants that have benefits to humans and those that do not. It is simply an overall estimate of antioxidant activity in a particular experiment. Due to the limited utility of this index, the USDA’s Nutrient Data Laboratory (NDL) removed the ORAC database from the NDL website .
Wild berries contain an impressive array of bioactive phytochemical compounds, which collectively present a range of biological activities targeting key mechanisms involved in healthy tissue development and aging [2, 3]. The human health-relevant bioactive properties of wild berries can be primarily attributed to their considerable diversity of polyphenolic constituents, typically exhibiting antioxidant, anti-inflammatory, and antimicrobial capabilities [4, 5]. The Nurses’ Health Study evaluated 16,000 participants regarding cognitive decline and consumption of berries over a 20-year period. Greater intakes of flavonoids particularly from strawberries and blueberries were associated with slower cognitive decline in older adults . This again supports the beneficial effects of blueberries.
Wild blueberries (
Various wild berry species endemic to Alaska and the circumpolar North that exhibit unique medicinal properties have long been appreciated by indigenous Arctic communities. Berry picking is a cherished tradition among all Alaskans that provides important physical and recreational activities for young and old alike. It has been an integral part of subsistence activities for thousands of years. Alaska is rich in wild edible berries that provide essential nutrients, especially vitamin C, and antioxidants for northern climates.
Interspecific differences, as well as environmental factors, such as geographic location and climatic variation, substantially influence the accumulation of berry phytochemicals and thus likely alter their profile of health-related bioactivities [9, 10, 11].
These experiments were designed to test the hypotheses that (1) wild blueberries would have beneficial short-term effects effect on healthy individuals (2) blueberries from Alaska would be more effective than those from the lower 48 (3) these effects would be seen across groups and species.
2.1 Comparing effects of wild Alaskan blueberries to those from the lower 48 for effects on stress, mood, and affective function in people in Fairbanks, Alaska
The Native Alaskan blueberries used in this experiment were hand-picked by the authors, and their associates, the summer before the experiment began, and frozen at −20 degrees Fahrenheit. These were low bush blueberries of large size, which are known to have high antioxidant value. The store-bought blueberries were purchased fresh from the local grocery store (Fred Meyers, Fairbanks, Alaska) around the same time. Half cup portions were prepackaged and labeled (A or B) and then placed in a refrigerator in the faculty lounge in the experimental locations.
2.1.1 Procedures for examining effects of blueberries
Custom surveys were created to enable participants to fully document the effects, positive, negative, or lack thereof, of the blueberries on their mental and physical health and well-being. Datasheets were turned in to the research supervisor at each site each week. There were 7 participants from Anne Wien Elementary (Fairbanks, AK) and 6 from an alternate site in Fairbanks (https://www.uafarc.com/overview), as well as 7 more from Hackett Middle School (Albany, NY) and 5 more from an alternate site in Albany later on for replication in the lower 48 States. (Experiment 2).
Experiment 2 was identical in procedure to experiment 1, the difference was the population that was tested. Experiment 2 took place at Hackett Middle School (https://www.albanyschools.org/schools/hackett/index) in Albany, New York about a year after experiment 1.
The University of Alaska Fairbanks Institutional Animal Care and Use Committee approved the animal care and experimental procedures (IACUC assurance number 497513).
Long-Evans rats were housed in polypropylene cages with wood shavings in a temperature (22 ± 1°C) and humidity (60–80%) controlled room of the Biological Research and Diagnostics (BiRD) Facility vivarium on a reversed 12:12 h dark-light cycle. Pups were weaned at 19–21 days of age and housed with same-sex littermates until the end of all experiments. Food (Purina Mills, Rat Diet, St. Louis, MO) and water were available
2.2.2 Estrous cycle
Female rats in proestrus were used for the study. The proestrus stage was determined daily by both visual and vaginal cytology methods. Vaginal cytology was performed on those females that showed visual signs of proestrus. The females for which proestrus was confirmed through cytology were subjected to behavioral testing the same day. This procedure was conducted daily until the desired sample sizes were achieved for a specific test. When the females cycled to their next proestrus, which was typically on the 4th or the 5th day, they were subjected to the next behavioral test in the schedule and this cycle was continued until all behavioral tests were completed. Typically, the no blueberry control week was the interval washout period between tests 1 and 3, which were randomized to blueberry condition.
2.2.3 Experimental design
All female rats were at least 60 days old at the start of the experiment. All behavioral tests were done in the dark phase of the light–dark cycle. For females, behavioral tests were conducted every 4–5 days depending on their cycle stage. All females underwent behavioral tests once every 5–10 days: open field (on day 5 or 10) and novel object recognition (on day 15 or 20). A minimum gap of 5 days for females between the two behavioral tests minimized the behaviors interfering with each other. An observer blind to the conditions of experimental animals and the hypothesized outcome of the study collected all data.
2.2.4 Open field
Behavior in the open field is used as a measure of exploration, anxiety, and locomotor behavior [12, 13]. The open field (76 cm x 57 cm x 35 cm) has a 48-square grid floor (6 x 8 squares, 9.5 cm/side): there is an overhead light illuminating the central squares (all but the 24 perimeter squares were considered central). Behavior was recorded by the ANYMaze video-tracking program (Stoelting Co., IL, USA). The apparatus was cleaned before and after each test. Per previous methods, rats were placed in the open field and the path of their exploration was recorded for five minutes. The number of squares entered by rats in the center or periphery of the grid was calculated and these data were added together to yield the total number of squares entered. Prior reports indicate that total square entries in this task are robustly modulated by the hormonal status of female rats and by steroid-sensitive manipulations [14, 15, 16]. Because the current study utilized a sample of female rats that were all matched on the phase of estrous cycle, motor differences were expected to be minimized. Thus, central square entries were utilized as an index of anti-anxiety, and total square entries as an index of thigmotaxis, and motor behavior. Additionally, engaging in this task provides habituation for object recognition, which occurs in the same box on the following days.
2.2.5 Object recognition
The object recognition task is a working memory task that primarily relies on cortical functioning and, to a lesser extent, hippocampal functioning [17, 18, 19]. This task was used as modified from previously published methods [20, 21, 22]. During training, rats are placed in a white open field (76 cm x 57 cm x 35 cm) in a brightly-lit testing room. Rats are allowed 3 min to explore the open field, which contains two identical objects in adjacent corners. These objects were colored spherical shapes (plastic toys in the shape of oranges). The time spent investigating the two identical objects (plastic toys) within a 5 cm distance in the open field arena was recorded for 3 min with the ANYMaze video tracking program (Stoelting.co, Chicago, IL). Rats were then taken out of the arena and returned to their holding cages for 4 hrs. After 4 hrs., one of the objects was replaced with a novel object of different shape and size, and animals were then reintroduced into the arena and allowed to explore the objects for 3 min. Time spent exploring the familiar and novel objects were recorded. The preference of one object over another was assessed through the Recognition Percentage, which is the time spent on the novel object relative to the time spent on both novel and familiar objects: [RI = TN/(TN + TF) x 100] where TN is time spent on the novel object and TF is time spent on the familiar object). A greater percentage of time spent exploring the novel object as a function of the total amount of time spent exploring both objects during testing (duration spent with novel object/(duration spent with novel object + duration spent with familiar object) Å x 100) is considered an index of enhanced cognitive performance in these tasks.
2.2.6 Statistical analyses: one-way repeated measure analyses of variance was utilized to examine the effects of the condition (Blueberries) on self ratings
Self-reports of beneficial effects on stress, anxiety, and cognition are reported among women participants in Fairbanks, Alaska (demographics in Table 1 left side, far) after 5 days of consumption of Alaskan blueberries > Lower-48 blueberries > no blueberries. Repeated measures analysis of variance revealed that there was an overall interaction between the type of blueberries and effects on self-ratings.
|Fairbanks, AK||Albany, NY|
|Location||Anne-Wien Eiementary School||Alternate site||Hackett Middle School|
|n = of participants||7||8||6||5|
|Age (avg. years)||42.3||33.6||40.0||48.7|
|Education (avg. years)||15.3||14.7||16.0||15.4|
2 Native Alaskan
2 Native Alaskan
1 African American
2 African American
1 African American
1 Native Alaskan
1 Native American
To confirm and extend these findings, the experiment was replicated at an alternative site in Fairbanks (see Table 1, left middle, for demographics). There were even greater statistically significant interactions between types of blueberries and effects on self-reports at this alternative site than at Anne Wien Elementary School. Ratings for weeks following consumption of Alaskan blueberries > Lower-48 blueberries >no blueberries for self-reports of feelings of calmness, being well-balanced, in control, on top of things, cognitive benefits. Thus, women in Alaska who consumed blueberries for 5 days experienced beneficial effects as per their self-ratings. The magnitude of these effects was greater at the alternative site. See Figure 3.
Self-reports of beneficial effects on stress, anxiety, and cognition are reported among women participants in Albany, New York after 5 days of consumption of Alaskan blueberries > Lower-48 blueberries > no blueberries. One-way, repeated analysis of variance revealed that there were overall interactions between the type of blueberries and effects on self-ratings. Some of the same patterns were observed among the participants at Hackett Middle School (Albany, NY) that were previously seen at Anne Wien Elementary (Fairbanks, AK). In particular, self-reports of feeling well-balanced, as well as in control and on top of things were higher in participants when they consumed Alaskan blueberries for a week compared to when they consumed Lower-48 blueberries or no blueberries. Demographics are reported in Table 1 center-right. See Figure 3 for results.
There were even greater statistically significant interactions between types of blueberries and effects on self-reports at this alternative site than at Hackett Middle School in Albany, NY. Ratings for weeks following consumption of Alaskan blueberries > Lower-48 blueberries ≥ no blueberries for self-ratings of feelings of calmness, well-balanced. See demographics in Table 1 and ratings in Table 2.
|Fairbanks-bird animal facility UAlaska||Albany-comprehensive neuropsychological services|
|Able to Control||1.5||2.3||3.8||1.3||2.4||2.7|
|On Top of Things||2.5||3.5||4.5||1.9||2.7||3.5|
There were 8 female Long-Evans rats in each of the 3 trial groups. Those who had 5 days of access to Alaskan blueberries made more total entries (245 entries) into the brightly lit open field than did those with access to blueberries from the Lower-48 (223 entries), as well as those with no blueberry supplementation (196 entries) in a 5-minute period. The number of central entries (all but peripheral squares) during this 5-minute task was also greater for rats with access to Alaskan blueberries (120 entries) than rats whose diets were supplemented with blueberries from the Lower-48 (113 entries) as well as rats whose diets were not supplemented (93 entries). The number of inner 8 entries (central squares of open field) during this 5-minute task was greater for rats with access to Alaskan blueberries (25 entries) compared to rats whose diets were supplemented with blueberries from the Lower-48 (19 entries), as well as rats whose diets were not supplemented (13 entries). When rats were tested in the novel object recognition task, those consuming Alaskan berries spent 70% of their time than the novel object, whereas rats consuming Lower-48 berries spent only 61% of their time with the object. Rats whose diets were not supplemented spent the least amount of time, 51% (no greater than chance levels), with the novel object during testing (See Figure 4).
The results of these experiments were consistent with the proposed hypotheses. First, blueberry consumption had beneficial short-term effects on healthy individuals. Blueberries had positive effects on the Alaskan participants’ health and well-being after 5 days of consumption. This was also observed in the Albany cohorts. Participants consuming blueberries rated their levels of calm, well-balanced, ability to control themselves, and stay on top of things, and cognitive benefit, higher than when they consumed no berries. Second, this effect was seen more obviously when participants consumed Alaskan blueberries. They rated themselves even higher in the aforementioned categories than when they consumed Lower-48 blueberries. This effect was not identical; however, in New York, data from participants show an effect of blueberries but not a statistically significant difference between Alaskan blueberries and berries from the Lower-48. Third, blueberries had similar patterns of effects in rats. Notably, in more global tasks, such as total entries and central entries in an open field, there was an effect of blueberries, irrespective of their source, to improve performance among rats. However, in more challenging tasks, such as the Inner 8 entries and the percent of time with novel object, consumption of Alaskan blueberries had a greater effect than did those from the lower-48. In summary, short term consumption of blueberries can have beneficial effects among some individuals. Further, the consumption of blueberries from Alaska had a more amplified effect than did berries from the Lower-48. Among Long Evans laboratory rats, Lower-48 or Alaskan blueberries increased motor activity and central entries (all non-peripheral squares) compared to control rats that did not consume any blueberries. However, rats consuming Alaskan blueberries made more Inner-8 entries, indicating that they were significantly bolder than rats that consumed Lower-48 blueberries or none at all. They also showed greater recollection and memory skills in the object recognition task than did those that consumed Lower-48 blueberries or none.
As mentioned in previous studies, blueberries as well as other fruits and vegetables have been linked to improving memory function as well as mood in older adults [23, 24, 25]. Our findings confirm and extend previous findings that blueberries can be beneficial to staving off cardiovascular disease, cognitive decline, and other age-related deleterious effects when consumed as part of a lifestyle. Here we show that short-term consumption of blueberries, 5 days of consumption, has perceived cognitive benefit among women age 30–55. Our participants’ self-ratings of their perceived cognitive benefit from short term consumption of blueberries, as well as high ratings in other categories, such as their ability to remain calm and well-balanced, show that short term consumption of blueberries has the ability to improve mood and mental well-being among women age 30–55. Further, in our third experiment, healthy adult rats’ performances benefited from blueberry consumption to have enhanced motor function, exploratory behavior, anti-anxiety effects, and learning. These latter findings are clearly objective, as they are not self-ratings and they demonstrate cross-species performance effects. Together, these findings confirm and extend the previous literature that older individuals can benefit from blueberry consumption as part of their lifestyle to indicate that short-term consumption of blueberries improves self-ratings of neurotypical women age 30–55 as well as objective effects on performance in rats. Another explanation may be that people in Alaska have greater access and exposure to foods with higher antioxidant levels than do people from the Lower 48 .
Consumption of Alaskan blueberries seemed to have a greater effect among participants in Alaska compared to participants in New York. An important question to ask is, what underlies this effect? One explanation could be that experiment 1 was conducted in Fairbanks, Alaska at the end of the winter season. This time of year in Alaska is also known as breakup and is associated with higher rates of suicide. There is tension in communities throughout Alaska caused by long harsh winters, and fresh blueberries may have had a greater effect on the moods and mental well-being of consumers during this sensitive time. Experiment 2 was conducted almost a full year later in Albany, New York, where the winters are much less harsh and dark. There may be some confounding variables due to these time frames. For example, the wild Alaskan blueberries had to be frozen for a longer period of time between experiments, 8 months for Experiment 1, versus 20 months, which may have caused a depletion in the potency of the Alaskan berries.
Another interesting finding relating to group differences was that the Alaskan blueberries had a greater effect among the office workers controls compared to the teachers in both control cohorts in Fairbanks and Albany. A likely explanation for this is that the office workers had a much calmer work environment than did the schoolteachers. They had greater control over their scope of work and when they engaged in their work activities, compared to being on a rigorous schedule with a limited break time that was preset and absolute. Further, office workers were not responsible for or surrounded by 20–30 children each day. They had a much quieter work environment. As such, the blueberries may have had a greater effect on individuals who were in a position to feel greater effects of the blueberries because they could engage in other behaviors to enhance their wellbeing (such as listening to music, while at work engaging in brief meditation activities, having time for self-care).
All experiments have limitations, one possible limitation of this experiment was that the pool of participants was small, only 6–8 participants in each experiment. However, the fact that significant results were observed and replicated across multiple domains indicates the power and consistency of the effects shown in all 5 experiments. This limitation was out of our control because all participants were volunteers, and some participant’s data were excluded because they did not participate in all 3 trial weeks. Another limitation is that a large majority of the participants in both trials were women, and mostly fell into the 30–55-year-old age range. A more diverse population next time might verify the results and show that the consumption of blueberries, especially wild Alaskan berries, are beneficial to everyone, and not just these populations. The notion that beneficial effects were seen in male rats suggests that this is a highly conserved effect and could be replicated on other populations. Another factor considered in this study is that living in Alaska is much closer to the earth and people in Alaska are much more affected by their environment. Experiences such as having 20 hours of sunlight each day in the summer and 20 hours of darkness in the winter have significant effects on mental and cognitive health and well-being. Also, the food that they eat is more likely to directly affect them; many Alaskans do not eat a strictly market diet but consume fish, game, and berries.
Blueberries are known to have a number of phytochemicals that contain several bioactive compounds that cause different physiological effects. One phytochemical are flavanols that contain the bioactive compounds
An important question is how do blueberries have beneficial effects through the mechanisms described above? Particularly relevant to this study are Vitamins D, A, E, and K (fat-soluble vitamins). Vitamin D is considered a (neuro) steroid that has effects on calcium, metabolism, and absorption of calcium and phosphorus from the intestine. Vitamin D exerts many other biological effects including processes involved in brain development and neuronal activity . Deficiency in Vitamin D is considered a risk factor for neuropsychiatric disorders, including post partum depression, major depression and schizophrenia [36, 37, 38, 39]. It causes alterations in brain structure and in dopamine and glutamate signaling, which are hallmarks of depression, anxiety, drug abuse and schizoaffective disorders. Functional foods rich in micronutrients that have the ability to stimulate PPAR, in addition to exert important anti-inflammatory actions may also induce significant mood- elevating properties, although the underlying mechanisms are not fully understood. PPAR might work in synergism with stimulation of neurosteroid biosynthesis to exert their beneficial effects by decreasing inflammation and relieving mood symptoms.
In summary, these experiments revealed that five days of blueberry consumption has beneficial effects on middle-aged women in Fairbanks, Alaska, as well as Albany, New York. The initial study in Fairbanks, Alaska (during “breakup season”), revealed a greater sensitivity and responsiveness to Alaskan blueberries than those from the Lower-48. Albeit, the second experiment, conducted in Albany, New York, showed a beneficial effect of blueberry consumption but not a differential effect between wild Alaskan and store-bought berries from the Lower-48. This may be due to the decomposition of antioxidants, flavonoids, and other important health factors caused by freezer storage for a full year. Our third experiment, using an animal model, conducted over the summer between the two human experiments, revealed beneficial effects of both Alaskan and Lower-48 blueberries when given as a supplement to male Long Evans rats. The rats that consumed blueberries had improved motor skills and exploratory behavior, irrespective of the source of blueberries. However, in more challenging tasks, such as entries into the Inner 8 squares in an open field (an anti-anxiety measure) and performance on the object recognition task, Alaskan blueberries had a greater effect on performance than did berries from the Lower-48 or no berries. To address the mechanism underlying these effects, we will be extracting the bioactive compounds and creating an Alaskan elixir to reassess their relative efficacy of Alaskan blueberries versus those from the Lower-48 on people as well as animal subjects.
In conclusion, it seems that blueberries can have short term effects as functional foods when consumed by individuals over a 5-day period. The precise mechanisms underlying these effects are unclear, however, differences between Fairbanks and Albany suggest that blueberries from a higher altitude may be more effective because they contain more flavonoids and more antioxidant effects. The beneficial effects of flavonoids may be mediated in part through actions of neurosteroids, such as Vitamin-D, allopregnanolone, 3α diol, which can inhibit deleterious effects of activation of PPAR and other physiological and pharmacological effects .
Research herein was supported in part by grants National Institute of Mental Health (MH06769801, RMH067698B) and the National Institute of General Medical Sciences of the National Institutes of Health (P20GM103395). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Assistance in the studies described herein provided by members of the laboratory, past, and present, is greatly appreciated.