Category: Contributors

Blue Zones and Their Role in the Diet-Mental Health Relationship (DMHR): A Three-Part Series Exploring the Interplay of Diet, Longevity, and Mental Health.

Posted on by CNP Staff

Editor’s Note: We begin our three-part series with an overview of the nine common characteristics that underlie Blue Zones. The second article will dive deeper into how diet and mental health may impact longevity.

In 2016, to explore the secrets to longevity, National Geographic Fellow and American Author Dan Buettner located five geographic locations on Earth yielding higher-than-average populations of people living beyond 100 years old, referred to as “centenarians.” The locations are Ikaria, Greece; Okinawa, Japan; Sardinia, Italy; Loma Linda, California; and Nicoya, Costa Rica (Buettner & Skemp, 2016). Buettner coined the term “Blue Zones,” defining them as communities that produce individuals who are ten times more likely to reach age 100 than the average

US citizen and prompting questions about what contributes to such extraordinarily healthful aging (Buettner & Skemp, 2016).

 

Blue zones are communities that produce individuals who are ten times more likely to reach age 100 than the average US citizen.

 

With the help of demographers, scientists, and anthropologists, Buettner identified nine common lifestyle characteristics among the Blue Zones that impact longevity: the Power 9 (Buettner & Skemp, 2016). These include: move naturally, purpose, downshift, 80% rule, plant slant, wine at 5, right tribe, loved ones first, and belong (Figure 1). His idea is that if genes dictate about 20% of life expectancy and lifestyle governs about 80%, the Power 9 can provide a blueprint for creating healthier populations and a higher human life expectancy worldwide (Herskind et al., 1996).

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Figure 1. Power 9 Blue Zone Characteristics

Power 9 characteristics can be sorted under four umbrella components — move naturally, right outlook, eat wisely, and connect.

Component 1: Move Naturally

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Rather than engaging in the exercise habits commonly seen in Western culture (e.g., high-intensity cardio, weight-lifting, marathon running), Blue Zone residents live in environments that foster daily, mindless movement. For example, Sardinians, often employed as shepherds, walk around five miles a day or more in tending to their animals (Buettner & Skemp, 2016). For others in Blue Zone communities, this routine movement may look like tending to a garden or walking across town for social commitments. 

 

Rather than engaging in the exercise habits commonly seen in Western culture, Blue Zone residents live in environments that foster daily, mindless movement. 

 

This movement leads to positive mental and physical outcomes. For instance, a 2021 study concluded that the more time Sardinians spent gardening, the better physical health they reported (Ruiu et al., 2022). The takeaway? Exceptionally long-living individuals move their bodies daily and in intuitive ways.

Component 2: Right Outlook

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Purpose

While the idea of “finding purpose” may hold varying names — the Okinawans call it “Ikiagi” and the Nicoyans call it “plan de Vida,” for example — the concept serves as a central theme within Blue Zones (Buettner & Skemp, 2016). Both “Ikiaki” and “plan de Vida” translate loosely to “why I wake up in the morning,” implying recognition of a life purpose. Buettner and Skemp (2016) found that having a life purpose may be worth up to seven years of additional life expectancy, which was supported by an association between a stronger purpose in life and decreased mortality found in a later study (Alimujiang et al., 2019). The discovery of such an individualized purpose appears to play a central role in the longevity of Blue Zone residents.

 

 Both “Ikiaki” and “plan de Vida” translate loosely to “why I wake up in the morning,” implying recognition of a life purpose.

 

Downshift

Downshift explores the idea of routines meant to release stress. The experience of stress is inevitable, and Blue Zone residents have created ways — unique to their religious ties and geographic regions — to release stress. For example, Adventists in Loma Linda pray, Okinawans take moments to remember their ancestors, and Ikiarians nap (Buettner & Skemp, 2016). In creating rituals to eliminate distress, bitcoin mixer individuals in Blue Zone regions defend themselves against stress-related illnesses such as coronary heart disease, cancer, and respiratory disorders (Salleh, 2008). By prioritizing outlets of escape from ambient stressors through downshift, Blue Zone residents create a culture supportive of a greater-than-average life expectancy.

 

Downshift explores the idea of routines meant to release stress. 

 

Component 3: Eat Wisely

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80% Rule 

Rather than eating until they feel they can’t take another bite, Blue Zone residents follow an 80-20 rule. This mantra, Hara Hachi Bu, created by Okinawans 2,500 years ago, encourages individuals to stop eating when they are 80% full (Buettner & Skemp, 2016). A consistent practice of this rule leads this population to consume fewer calories and consequently have lower energy intake (Fukkoshi et al., 2015). 

 

The Okinawan mantra Hara Hachi Bu encourages individuals to stop eating when they are 80% full. 

 

This practice begs individuals to practice mindfulness, as recognizing one’s satiety requires an understanding of internal cues. Blue Zone residents are encouraged to chew slowly, take deep breaths, and be present in their bodies to honor their hunger cues and avoid overeating. As stated above, by not overeating, these populations subsequently experience a lower input of calories and collateral energy, which is associated with human longevity (Willcox et al., 2006). 

 

In eating until 80% full, Blue Zone residents are pushed to chew slowly, take deep breaths, and be present in their bodies to honor their hunger cues and avoid overeating. 

 

Wine at 5

All Blue Zone populations, excluding Adventists in Loma Linda, regularly and moderately consume alcohol (Buettner & Skemp, 2016). The frequent alcohol of choice is wine, specifically, Cannonau, a red wine native to Sardinia (Buettner & Skemp, 2016). Red wine contains large amounts of antioxidants — polyphenols — which stabilize free radicals and counteract oxidative stress. The latter is a known contributor to detrimental neurological conditions such as Parkinson’s disease, Alzheimer’s disease, and depression, all of which contribute to increased mortality (Pizzino et al., 2017). Consuming quality red wine regularly and socially provides an influx of antioxidants to help defend against such diseases, likely positively contributing to longer-than-average life spans among Blue Zone residents.

 

Red wine contains large amounts of antioxidants — polyphenols — which stabilize free radicals and counteract oxidative stress. 

 

Plant Slant

Most centenarian diets are plant-based, with a significant intake of vegetables, beans, and whole grains. Ikarians, largely due to their proximity to the Mediterranean, eat a Mediterranean diet filled with lots of fruit, olive oil, vegetables, and plant-based proteins such as nuts, beans, and seeds. Adventists take their dietary habits from the Bible and consume a vegan diet full of legumes, leafy vegetables, and nuts. Nicoyans consume little to no processed foods and emphasize antioxidant-rich fruits in their diet (Buettner & Skemp, 2016). Though their diets vary slightly based upon location and community values, all Blue Zone diets have a plant-based theme associated with longevity (Norman & Klaus, 2020).

Component 4: Connect

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Right Tribe 

The idea of “finding your people” is one that lots of individuals strive to achieve. Maintaining satisfying social ties with friends and family and living a socially-oriented lifestyle can decrease feelings of loneliness and contribute to beneficial mental health outcomes (Hitchcott et al., 2017). In Okinawa, children aged five are put into moai, committed social networks that exist indefinitely (Buettner & Skemp, 2016). These social circles provide individuals with the comfort of knowing they will always have support, whether financial, emotional, or otherwise. Nurturing healthy relationships like those in moai substantially increases one’s likelihood of longevity, explaining why this effort is so important for Blue Zone folk (Holt-Lunstad et al., 2010).

Loved Ones First

Another central theme in Blue Zone territories is keeping family close. Blue Zone residents, whether living near family or in intergenerational homes, emphasize investing in their families (Buettner & Skemp, 2016). In collectivist cultures such as Japan, harmonious relationships with family play a role in supporting psychological well-being (Kitayama et al., 2020). The same goes for the strong social support from family members in Italy; it is associated with few depressive symptoms later in life (Carpiniello et al., 1989). Living with aging parents and grandparents in intergenerational homes also lowers children’s disease and mortality rates (Buettner & Skemp, 2016). Prioritizing loved ones plays a role in longevity, as committing to a partner, commonly seen throughout Blue Zones, can add up to three years of life expectancy (Buettner & Skemp, 2016).

 

Prioritizing loved ones plays a role in longevity and can add up to three years of life expectancy.

 

Belong

Most centenarians in Blue Zone communities belong to a faith-based community, and all but five of 263 Blue Zone centenarians interviewed by Buettner belonged to a specific one (Buettner & Skemp, 2016). Denomination does not interfere with the impact of belonging to such a community, as religiosity is a protective factor for aging (Krause, 2003). Attending a faith-based service four times per month can add anywhere between four and 14 years of life expectancy. Older adults who gain a sense of meaning in life from religion also tend to report higher levels of mental health benefits such as life satisfaction, self-esteem, and optimism (Buettner & Skemp, 2016; Krause, 2003). Overall, the longest-living communities tend to incline toward faith-based groups.

 

Older adults who gain a sense of meaning from religion also report higher levels of mental health benefits such as life satisfaction, self-esteem, and optimism. 

 

What now?

The association of mental health and longevity, combined with the knowledge that there are pockets of the world producing abnormal amounts of centenarians, urges the exploration of what mental health efforts Blue Zone residents are implementing into their daily lives that may be impacting mortality.

The Power 9 provides distinct factors central to Blue Zone communities. Physical movement, mental health, diet, and social connection appear critical to uncovering the secrets of longevity and well-being. Yet many questions remain to be answered. How much influence does one factor have over the others? What role does food, specifically, play in the mental health of Blue Zone residents?

 

Physical movement, mental health, diet, and social connection appear critical to uncovering the secrets of longevity and well-being. 

 

More research on Blue Zones is expected in the upcoming years. As our understanding of the diet-mental health relationship (DMHR) evolves and becomes more central to various healthcare settings, Blue Zones may provide a unique opportunity to boost healthy living. 

The interplay of diet and mental health and its impact on longevity will be further explored in the context of Blue Zone regions in two upcoming articles.

 

References

Alimujiang, A., Wiensch, A., Boss, J. (2019) Association between life purpose and mortality among US adults older than 50 years. JAMA Network Open, 2(5). doi:10.1001/jamanetworkopen.2019.4270

Buettner, D., Skemp, S. (2016). Blue zones: lessons from the world’s longest lived. Sage Journals, 10(5), 318-321. https://doi.org/10.1177/1559827616637066

Carpiniello B., Carta M. G., Rudas N. (1989). Depression among elderly people. A psychosocial study of urban and rural populations. Acta Psychiatrica Scandinavica, 80(5), 445–450. Doi: 10.1111/j.1600-0447.1989.tb03004.x

Fastame, M.C., Hitchcott, P.K., Mulas, I., Ruiu, M., Penna, M.P. (2018). Resilience in elders of the Sardinian blue zone: an explorative study. Behavioral Sciences, 8(3), doi: 10.3390/bs8030030

Fukkoshi, Y., Akamatsu, R., Shimpo, M. (2016). The relationship of eating until 80% full with types and energy values of food consumed. Science Direct, 17, 153-156. https://doi.org/10.1016/j.eatbeh.2015.03.001

Herskind, A.M., McGue, M., Holm, N.V., Sorensen, T.I.A., Harvald, B., Vaupel, J.W. (1996). The heritability of human longevity: a population-based study of 2872 Danish twin pairs born 1870-1900. Human Gent, 97(3), 319-323. DOI: 10.1007/BF02185763

Hitchcott, P.K., Fastame, M.C., Ferrai, J., Penna, M.P. (2017). Psychological well-being in Italian families: an exploratory approach to the study of mental health across the adult life span in blue zone. Europe’s Journal of Psychology, 13(3), 441-454. Doi:

10.5964/ejop.v13i3.1416

Holt-Lunstad, J., Smith, T.B., Layton, J.B. (2010). Social relationships and mortality risk: a meta-analytic review. Plos Medicine, 7(7). https://doi.org/10.1371/journal.pmed.1000316

Kitayama S., Markus H. R., Kurokawa M. (2000). Culture, emotion, and well-being: good feelings in Japan and the United States. Cognition and Emotion, 14(1), 93–124. Doi: 10.1080/026999300379003

Krause, N. (2003). Religious meaning and subjective well-being in late life. The Journals of Gerontology, 58(3), S160-S170. https://doi.org/10.1093/geronb/58.3.S160

Norman, K., Klaus, S. (2020). Veganism, aging and longevity: new insight into old concepts. Current Opinion in Clinical Nutrition and Metabolic Care, 23(2), 145-150. doi:10.1097/MCO.0000000000000625

Pizzino, G., Irrera, N., Cucinotta, M., Pallio, G., Mannino, F., Arcoraci, V., Squadrito, F., Altavilla, D., Bitto, A. (2017). Oxidative stress: harms and benefits for human health. Oxidative Medicine and Cellular Longevity, 2017: 8416763. salgen.it doi: 10.1155/2017/8416763

Ruiu, M., Carta, V., Deiana, C., Fastame, M.C. (2022). Is the Sardinian blue zone the new Shangri-la for mental health? Evidence on depressive symptoms and its correlates in late adult life span. Aging Clinical and Experimental Research, 34, 1315-1322.https://doi.org/10.1007/s40520-021-02068-7

Salleh, M.R. (2008). Life event, stress, and illness. The Malaysian Journal of Medical Sciences, 15(4), 9-18.

Willcox, D.C., Willcox, B.J., Todoriki, H., Curb, J.D., Suzuki, M. (2006). Caloric restriction and human longevity: what we can learn from the Okinawans. Biogerontology, 7, 173-177. https://doi.org/10.1007/s10522-006-9008-z

 

Refined Grains May Increase the Risk for Cardiovascular Diseases and Affect the Diet-Mental Health Relationship

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As technological advances revolutionized agriculture and food science, foods are now processed at industrial scales and supplied in abundance to meet global demands. However, changes in food production have led to the creation of items that are now consumed in excess, particularly products with refined grains and added sugars. 

 

Changes in food production have led to the creation of items that are now consumed in excess, particularly products with refined grains and added sugars. 

 

Previous studies have reported a positive association between eating refined grains and greater risk factors for cardiovascular diseases (CVD) among U.S. adults (Howard & Wylie-Rosett, 2002; Yang et al., 2014; Dehghan et al., 2017). Both refined and whole grains contribute significantly to the global daily caloric intake (Kearney, 2010). 

Being that grains are pervasive in the global diet, it is critical to understand their impact on physical health and the diet-mental health relationship. Compared to whole grains, which have been associated with reduced risks of CVDs and mortality (Ye, et al., 2012), refined grains and their health outcomes have yet to be fully understood.

 

Being that grains are pervasive in the global diet, it is critical to understand their impact on physical health and the diet-mental health relationship.

 

To bridge this knowledge gap, Swaminathan et al. (2021) led a prospective cohort study (PCS) to examine the relationship between the consumption of grains and CVDs. A PCS design is longitudinal and evaluates participants that are similar but differ in one key aspect for comparison of the same outcome. Utilizing data in their analysis from 2003 to 2019 from the Prospective Urban Rural Epidemiology (PURE) study, researchers compared the diets of participants from low-, middle-, and high-income countries in an effort to observe how different intake levels of refined grains, whole grains, and white rice are associated with CVDs and mortality (Corsi et al., 2013;  Swaminathan et al., 2021). This study did not compare the relationship between CVDs and no, or minimal, grain consumption (as in a ketogenic or low-carbohydrate diet).

 

Refined grains are defined as products modified to have low fiber content like white bread, dessert/pastries, processed noodles/pasta, and breakfast cereals.

 

White rice was stratified as a group separate from refined and whole grains as 60% of the participants in the PURE dataset were from Asia, where white rice is an integral part of their diet. Furthermore, refined grains are defined as products modified to have low fiber content like white bread, dessert/pastries, processed noodles/pasta, and breakfast cereals. In contrast, whole grains are foods made with intact grains like oats and whole wheat, which have higher fiber content. 

The authors found that a higher dietary intake of refined grains in countries like China and in South East Asia is significantly associated with higher risks of mortality, major CVDs, and comorbidities such as high blood pressure, myocardial infarction, strokes, and heart failure (Figure 1). This relationship was not observed in regions of South Asia where white rice constitutes the highest grain intake or where whole grain is the staple, as in Africa. Particularly for diets comprised largely of white rice, there is less concern about high intake as the countries whose individuals commonly eat white rice do so at controllable levels with their meals as it is customary to pair it with other protein- or vegetable-based dishes.

 

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Figure 1. Eating high amounts of refined grains is significantly associated with greater risks for mortality and developing cardiovascular diseases. This relationship was not found for whole-grain foods like oatmeal and wheat bread.

 

A higher dietary intake of refined grains in countries like China and in South East Asia is significantly associated with higher risks of mortality, major CVDs, and comorbidities such as high blood pressure, myocardial infarction, strokes, and heart failure. 

 

In their discussion, the authors hypothesized that this outcome is a direct result of the production process of refined grains, which makes their sugar content more easily absorbed into the bloodstream. As a result, this elevates insulin levels and causes blood glucose to decrease, ultimately tricking the brain into thinking it is still hungry and promoting feeding behaviors that lead to overeating, obesity, and CVDs. While the implications of these results on cardiovascular health and the ways that diet can affect our physical (and therefore psychological) well-being demand further research, Swaminathan et al. shed light agoradesign.it on the importance of choosing a balanced diet to maintain physical and dietary health.

 

Processed refined grains ultimately trick the brain into thinking it is still hungry and promote feeding behaviors that lead to overeating, obesity, and CVDs. 

 

Find these and more studies showing how the dietary intake of sugar and processed foods affect mood, brain, and behavior in the Nutritional Psychology Research Library (NPRL). You can also sign up for the CNP Newsletter to stay informed!

 

References

Corsi, D. J., Subramanian, S. V., Chow, C. K., McKee, M., Chifamba, J., Dagenais, G., Diaz, R., Iqbal, R., Kelishadi, R., Kruger, A., Lanas, F., López-Jaramilo, P., Mony, P., Mohan, V., Avezum, A., Oguz, A., Rahman, M. O., Rosengren, A., Szuba, A., Li, W., … Yusuf, S. (2013). Prospective Urban Rural Epidemiology (PURE) study: Baseline characteristics of the household sample and comparative analyses with national data in 17 countries. American heart journal, 166(4), 636–646.e4. https://doi.org/10.1016/j.ahj.2013.04.019 

Dehghan, M., Mente, A., Zhang, X., Swaminathan, S., Li, W., Mohan, V., Iqbal, R., Kumar, R., Wentzel-Viljoen, E., Rosengren, A., Amma, L. I., Avezum, A., Chifamba, J., Diaz, R., Khatib, R., Lear, S., Lopez-Jaramillo, P., Liu, X., Gupta, R., Mohammadifard, N., … Prospective Urban Rural Epidemiology (PURE) study investigators (2017). Associations of fats and carbohydrate intake with cardiovascular disease and mortality in 18 countries from five continents (PURE): a prospective cohort study. Lancet (London, England), 390(10107), 2050–2062. https://doi.org/10.1016/S0140-6736(17)32252-3 

Howard, B. V., & Wylie-Rosett, J. (2002). Sugar and cardiovascular disease: A statement for healthcare professionals from the Committee on Nutrition of the Council on Nutrition, Physical Activity, and Metabolism of the American Heart Association. Circulation, 106(4), 523–527. https://doi.org/10.1161/01.cir.0000019552.77778.04

Kearney J. (2010). Food consumption trends and drivers. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 365(1554), 2793–2807. https://doi.org/10.1098/rstb.2010.0149 

Swaminathan, S., Dehghan, M., Raj, J. M., Thomas, T., Rangarajan, S., Jenkins, D., Mony, P., Mohan, V., Lear, S. A., Avezum, A., Lopez-Jaramillo, P., Rosengren, A., Lanas, F., AlHabib, K. F., Dans, A., Keskinler, M. V., Puoane, T., Soman, B., Wei, L., Zatonska, K., … Yusuf, S. (2021). Associations of cereal grains intake with cardiovascular disease and mortality across 21 countries in Prospective Urban and Rural Epidemiology study: prospective cohort study. BMJ cipf-es.org (Clinical research ed.), 372, m4948. https://doi.org/10.1136/bmj.m4948 

Yang, Q., Zhang, Z., Gregg, E. W., Flanders, W. D., Merritt, R., & Hu, F. B. (2014). Added sugar intake and cardiovascular diseases mortality among US adults. JAMA internal medicine, 174(4), 516–524. https://doi.org/10.1001/jamainternmed.2013.13563 

Ye, E. Q., Chacko, S. A., Chou, E. L., Kugizaki, M., & Liu, S. (2012). Greater whole-grain intake is associated with lower risk of type 2 diabetes, cardiovascular disease, and weight gain. The Journal of nutrition, 142(7), 1304–1313. https://doi.org/10.3945/jn.111.155325

Eating Fermented Foods with Live Microbes May Improve Dietary Health

Posted on by CNP Staff

Fermented foods—like kimchi and yogurt—and probiotic supplements have been associated with improved metabolic health and, consequently, stronger immunity and reduced risk against various cancers (Savaiano et al., 2021; Wastyk et al., 2021). What these foods and supplements have in common is the presence of living microorganisms (Montville, 2004; Jeddi et al., 2014; Ziyaina et al., 2018). In fact, raw and unpeeled fruits and vegetables, dairy, and certain proteins contain dietary microbes that have been demonstrated to benefit human health (Roselli et al., 2021; Marco et al., 2022). 

Note: this article/study does not specifically explore beneficial or pathogenic microbes; rather, the authors are interested in determining how many “live” microbes are found in foods within the Western diet. To do this, they used preexisting data to estimate microbial content by classifying the foods eaten by participants as low, medium, or high amounts.

 

Raw and unpeeled fruits and vegetables, dairy, and certain proteins contain dietary microbes that have been demonstrated to benefit human health.

 

However, compared to other macronutrients such as carbohydrates, fats, and proteins which are reported on nutrition fact labels and databases, it is not clear how much of the Western diet is actually composed of foods containing live dietary microbes and, moreover, the percentage of U.S. adults and children who consume them. Addressing this knowledge gap is not only imperative in establishing safe daily intake values of live microbes but also encourages further clinical studies to investigate the long-term health benefits they may provide.

To quantify the level of microbes across food groups and the proportion of U.S. residents that ingest them, Marco et al. conducted a 2022 study that analyzed published dietary data from the National Health and Nutrition Examination Survey (NHANES), an ongoing study led by the CDC’s National Center for Health Statistics. NHANES study participants are selected through statistical sampling and information is collected through both in-home interviews and physical examinations at designated health centers. 

For their retrospective analysis, Marco et al. used 24-hour dietary recall results obtained from 74,466 adults and children, dating from 2001 to 2018. Their study aimed to use pre-existing data to estimate the general amounts of microbes contained in food items reported in the NHANES study, classify each item as low-, medium-, or high-microbial content, and, ultimately, approximate the percentage of U.S. adults and children who consume these live microbes.

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Figure 1. Representative image depicting the approximate levels of live microbes across different food groups and the increasing U.S. dietary intake of medium to medium-high levels of microbes from 2001 to 2018 (based on Marco et al., J Nutr, 2022).

 

They estimated that processed foods (which are usually pasteurized to remove harmful microbes), meats, seafood (raw and cooked), and peeled fresh fruits and vegetables contained low levels of microbes. Fruit juices, unpeeled fruits and vegetables (skin is still on, so microbes can live on the surface), and fermented foods like sauerkraut, miso, and kimchi have medium levels. Fermented and cultured dairy products like milk, yogurt, sour cream, and cheese were classified as high (Figure 1). 

 

Processed foods (which are usually pasteurized to remove harmful microbes), meats, seafood (raw and cooked), and peeled fresh fruits and vegetables contained low levels of microbes.

 

While their study attempted to categorize different food groups based on their microbial content through previous studies and expert opinions, Marco et al. recognize that their findings are limited by possible biases and inaccuracies in how items were classified. Nevertheless, after quantifying the levels of microbes across different foods in the Western diet, the authors approximated that greater than 50% of U.S. adults and children eat medium to medium-high amounts of live microbes, with this being an increasing trend over an 18-year period (Marco et al., 2022). 

Out of all food groups categorized, fruits, vegetables, and fermented dairy constituted the majority of live microbes in the U.S. diet based on the study’s classification system. Despite the numerous approaches and regulatory guidelines implemented to clean fruits and vegetables for human consumption, Marco et al. report them to be a notable source of microbes that can actually be providing key nutrients such as calcium, fiber, and potassium, which are lacking in the diets of adults and children (USDA and USDHHS, 2020). 

 

Out of all food groups categorized, fruits, vegetables, and fermented dairy constituted the majority of live microbes in the U.S. diet. 

 

This result is not surprising but underscores the need for further research on the validity of the study’s approach and the significance of these microbes on fruits and vegetables. In comparison, the authors expected fermented dairy products to be the major source of microbes as the process of fermentation—in which foods composed of carbohydrates convert to alcohol or organic acids used in various cuisines—relies on the biological activities of microorganisms. Ultimately, Marco et al. presented interesting results that provide a foundation for future research to better explore the relationship between the consumption of live microbes and dietary health outcomes. 

 

References

Jeddi, M. Z., Yunesian, M., Gorji, M. E., Noori, N., Pourmand, M. R., & Khaniki, G. R. (2014). Microbial evaluation of fresh, minimally-processed vegetables and bagged sprouts from chain supermarkets. Journal of health, population, and nutrition, 32(3), 391–399.

Marco, M. L., Hutkins, R., Hill, C., Fulgoni, V. L., Cifelli, C. J., Gahche, J., Slavin, J. L., Merenstein, D., Tancredi, D. J., & Sanders, M. E. (2022). A Classification System for Defining and Estimating Dietary Intake of Live Microbes in US Adults and Children. The Journal of nutrition, nxac074. Advance online publication. https://doi.org/10.1093/jn/nxac074 

Montville, R., & Schaffner, D. W. (2004). Statistical distributions describing microbial quality of surfaces and foods in food service operations. Journal of food protection, 67(1), 162–167. https://doi.org/10.4315/0362-028x-67.1.162 

Roselli, M., Natella, F., Zinno, P., Guantario, B., Canali, R., Schifano, E., De Angelis, M., Nikoloudaki, O., Gobbetti, M., Perozzi, G., & Devirgiliis, C. (2021). Colonization Ability and Impact on Human Gut Microbiota of Foodborne Microbes From Traditional or Probiotic-Added Fermented Foods: A Systematic Review. Frontiers in nutrition, 8, 689084. https://doi.org/10.3389/fnut.2021.689084 

Savaiano, D. A., & Hutkins, R. W. (2021). Yogurt, cultured fermented milk, and health: a systematic review. Nutrition reviews, 79(5), 599–614. https://doi.org/10.1093/nutrit/nuaa013 

U.S. Department of Agriculture and U.S. Department of Health and Human Services (2020). Dietary Guidelines for Americans, 2020-2025. 9th Edition. Available at DietaryGuidelines.gov.

Wastyk, H. C., Fragiadakis, G. K., Perelman, D., Dahan, D., Merrill, B. D., Yu, F. cactusmeraviglietina.it B., Topf, M., Gonzalez, C. G., Van Treuren, W., Han, S., Robinson, J. L., Elias, J. E., Sonnenburg, E. D., Gardner, C. D., & Sonnenburg, J. L. (2021). Gut-microbiota-targeted diets modulate human immune status. Cell, 184(16), 4137–4153.e14. https://doi.org/10.1016/j.cell.2021.06.019 

Ziyaina, M., Govindan, B. N., Rasco, B., Coffey, T., & Sablani, S. S. (2018). Monitoring Shelf Life of Pasteurized Whole Milk Under Refrigerated Storage Conditions: Predictive Models for Quality Loss. Journal of food science, 83(2), 409–418. https://doi.org/10.1111/1750-3841.13981 

Whole Food Dietary Interventions to Improve Depression Symptoms

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Depression is a debilitating mental illness that often manifests with physical symptoms such as fatigue and cognitive impairments. Globally, it is a prevalent disability that can be treated through a combination of evidence-based therapies and medications. While these are viable options for individuals seeking help, their general effectiveness across diverse populations has yet to be established and, importantly, may not be suitable for those whose symptoms make it difficult to pursue treatment consistently. 

In seeking alternatives that are more feasible to implement in addressing chronic depression, numerous epidemiological studies have uncovered an inverse correlation between diet quality and depression (Molendijk et al., 2018; Lassale et al., 2019; Wu et al., 2020). Biological mechanisms—like inflammation, oxidation, and stress—have been proposed as drivers of depression, and diets enriched with polyphenol and omega-3 fatty acids have proved effective in improving depressive symptoms (Jang et al., 2020, Marx et al., 2020). 

 

Numerous epidemiological studies have uncovered an inverse correlation between diet quality and depression.

 

However, the relationship between diet and mental health is difficult to elucidate as research mostly focuses on micronutrients, which humans do not eat in isolation (O’Neill et al., 2022). In an effort to clarify the positive impact of dietary interventions on depression, O’Neill et al. conducted a systematic review of clinical trials emphasizing the effects of whole food diets on depressive symptoms.

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Academy of Nutrition and Dietetics Quality Criteria (ANDQCC) Checklists, the authors reviewed results from randomized control trials (RCTs) in which only whole foods/diet dietary interventions were used to address depression (Page et al., 2021). PRISMA was utilized to ensure appropriate studies were included in the literature search and ANDQCC was leveraged to reduce the risk of bias in the selected studies by assessing their validity with a series of quality criteria questions. Moreover, the authors intentionally limited their reviews of RCTs from 2000 to 2021 to produce conclusions that better reflect today’s dietary landscape and the possible benefits of whole foods/diets in treating depression.

From a total of 3,030 studies, seven studies were ultimately included and analyzed in their systematic review, representing adult populations from the USA, the UK, Australia, and Korea. These studies utilized whole food interventions—characterized by the consumption of minimally processed foods—and/or whole diet interventions that carefully regulated dietary intake to evaluate how they improved depressive symptoms according to standardized depression measures (O’Neill et al., 2022). 

Across all studies, these interventions reduced depressive symptoms and, in particular, whole diet interventions involving flavonoids led to the greatest decrease in depression scores. These phytochemicals are abundant in Mediterranean diets and have been demonstrated to alleviate depression through antioxidative and anti-inflammatory processes (Godos et al., 2018; Bayes et al., 2020; Ventriglio et al., 2020). 

%learn about nutrition mental health %The Center for Nutritional Psychology

Figure 1. Whole diets rich in flavonoids were associated with lower depressive symptoms, most likely through antioxidative and anti-inflammatory effects, as reported through standardized depression scores. 

Flavonoids are plant compounds that are obtainable through a diet rich in fruits and vegetables. There are six primary types of flavonoids, each with health-promoting anti-inflammatory effects, along with antioxidant properties which protect cells from oxidative damage. Flavonoids have been identified in the literature as natural antidepressants with additional benefits in reducing the risks of heart disease and diabetes (Hritcu et al., 2017; Pannu et al., 2021). Sources of flavonoids include dark leafy greens, vegetables, berries, seeds, nuts, beans, and grains.  

 

Whole diet interventions involving flavonoids led to the greatest decrease in depression scores. 

 

For more information on how plant compounds influence brain function and mental health, visit the Center for Nutritional Psychology (CNP) Nutritional Psychology Research Libraries (NPRLs). 

 

References

Bayes, J., Schloss, J., & Sibbritt, D. (2020). Effects of Polyphenols in a Mediterranean Diet on Symptoms of Depression: A Systematic Literature Review. Advances in nutrition (Bethesda, Md.), 11(3), 602–615. https://doi.org/10.1093/advances/nmz117 

Godos, J., Castellano, S., Ray, S., Grosso, G., & Galvano, F. (2018). Dietary Polyphenol Intake and Depression: Results from the Mediterranean Healthy Eating, Lifestyle and Aging (MEAL) Study. Molecules (Basel, Switzerland), 23(5), 999. https://doi.org/10.3390/molecules23050999 

Gomez-Pinilla, F., Foster, J. A., Cani, P. D., Thuret, S., Staudacher, H. M., … Jacka, F. N. (2021). Diet and depression: exploring the biological mechanisms of action. Molecular psychiatry, 26(1), 134–150. https://doi.org/10.1038/s41380-020-00925-x 

Hritcu, L., Ionita, R., Postu, P. A., Gupta, G. K., Turkez, H., Lima, T. C., Carvalho, C., & de Sousa, D. P. (2017). Antidepressant Flavonoids and Their Relationship with Oxidative Stress. Oxidative medicine and cellular longevity, 2017, 5762172. https://doi.org/10.1155/2017/5762172 

Jang, S. H., Woo, Y. S., Lee, S. Y., & Bahk, W. M. (2020). The Brain-Gut-Microbiome Axis in Psychiatry. International journal of molecular sciences, 21(19), 7122. https://doi.org/10.3390/ijms21197122 

Lassale, C., Batty, G. D., Baghdadli, A., Jacka, F., Sánchez-Villegas, A., Kivimäki, M., & Akbaraly, T. (2019). Healthy dietary indices and risk of depressive outcomes: a systematic review and meta-analysis of observational studies. Molecular psychiatry, 24(7), 965–986. https://doi.org/10.1038/s41380-018-0237-8 

Marx, W., Lane, M., Hockey, M., Aslam, H., Berk, M., Walder, K., Borsini, A., Firth, J., Pariante, C. M., Berding, K., Cryan, J. F., Clarke, G., Craig, J. M., Su, K. P., Mischoulon, D., 

Molendijk, M., Molero, P., Ortuño Sánchez-Pedreño, F., Van der Does, W., & Angel Martínez-González, M. (2018). Diet quality and depression risk: A systematic review and dose-response meta-analysis of prospective studies. Journal of affective disorders, 226, 346–354. https://doi.org/10.1016/j.jad.2017.09.022 

O’Neill, S., Minehan, M., Knight-Agarwal, C. R., & Turner, M. (2022). Depression, Is It Treatable in Adults Utilising Dietary Interventions? A Systematic Review of Randomised Controlled Trials. Nutrients, 14(7), 1398. https://doi.org/10.3390/nu14071398 

Page, M. J., McKenzie, J. E., Bossuyt, P. M., Boutron, I., Hoffmann, T. C., Mulrow, C. D., Shamseer, L., Tetzlaff, J. M., Akl, E. A., Brennan, S. E., Chou, R., Glanville, J., Grimshaw, J. M., Hróbjartsson, A., Lalu, M. M., Li, T., Loder, E. W., Mayo-Wilson, E., McDonald, S., McGuinness, L. A., … Moher, D. (2021). The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ (Clinical research ed.), 372, n71. https://doi.org/10.1136/bmj.n71 

Pannu, A., Sharma, P. C., Thakur, V. K., & Goyal, R. K. (2021). Emerging Role of Flavonoids as the Treatment of Depression. Biomolecules, 11(12), 1825. https://doi.org/10.3390/biom11121825 

Ventriglio, A., Sancassiani, F., Contu, M. P., Latorre, M., Di Slavatore, M., Fornaro, M., & Bhugra, D. (2020). Mediterranean Diet and its Benefits on Health and Mental Health: A Literature Review. Clinical practice and epidemiology in mental health : CP & EMH, 16(Suppl-1), 156–164. https://doi.org/10.2174/1745017902016010156 

Wu, P. Y., Lin, M. Y., & Tsai, P. S. (2020). Alternate healthy eating index and risk of depression: A meta-analysis and systemematic review. Nutritional neuroscience, 23(2), 101–109. https://doi.org/10.1080/1028415X.2018.1477424 

 

Can Three Weeks of Healthy Eating Improve Depressive Symptoms in Young People?

Posted on by CNP Staff

In this recent study published in October of 2019, Dr. Heather Francis and her colleagues conducted a randomized controlled trial to determine whether a brief 3-week healthy dietary intervention could reduce symptoms of depression in young adults (click here to watch a 2-minute CNP Diet-Mental Health Break video on this research study). This study is important because it points to the positive (and rapid) effects of a healthy diet on mental health. This comes on the heels of another exciting study published by Dr. Felice Jacka and her colleagues — the pioneers of the evidence-based field of Nutritional Psychiatry: The ‘SMILES Trial,’ which was the first intervention study to test dietary improvement as a treatment strategy for depression.

The authors of the current study were interested in conducting research on the young adult population due to the importance of establishing healthy eating patterns during this period, as well as the importance of lowering the increased risk of the development of depression and mental disorders that occur simultaneously.

Dr. Francis and her colleagues hypothesized that engaging in a brief dietary intervention involving both increasing healthy foods and decreasing unhealthy foods could result in reduced levels of depression.

All participants were undergraduates who both habitually consumed a poor diet (as assessed by a dietary fat and sugar screener tool (DFS)) and didn’t comply with Australian guidelines for healthy eating. All participants scored at Moderate or Higher depression levels on the Depression, Anxiety and Stress Scale-21 Depression subscale (DASS-21-D).

Thirty-eight participants were partitioned into two groups: one engaging in the healthy eating intervention and one remaining in the habitual poor diet group.

The healthy eating group participants were instructed to increase their intake of vegetables, fruits, whole grains, protein, unsweetened dairy, fish, nuts and seeds, olive oil, and healthy spices. They were also instructed to decrease their intake of refined carbohydrates, sugar, fatty or processed meats, and soft drinks. Diet compliance was measured via self-report questionnaires and spectrophotometry.

The Diet group had significantly lower self-reported depression symptoms than the Control Group. Results were followed up during a check-in three months later and remained stable.

This study demonstrated that young adults with increased depression symptoms can successfully comply with and engage in a brief dietary intervention that can reduce symptoms of depression. Thanks to Dr. Francis and her colleagues for conducting this research!

Study: Francis, H. M., Stevenson, R. J., Chambers, J. R., Gupta, D., Newey, B., & Lim, C. K. (2019). A brief diet intervention can reduce symptoms of depression in young adults – A randomised controlled trial. PloS one, 14(10), e0222768. https://doi.org/10.1371/journal.pone.0222768

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