In a March 2022 Scientific Brief, the World Health Organization reported, “the COVID-19 pandemic has had a severe impact on the mental health and wellbeing of people around the world while also raising concerns of increased suicidal behaviour.”  More specifically, WHO noted that “the COVID-19 pandemic has led to a 27.6% increase in cases of major depressive disorder and a 25.6% increase in cases of anxiety disorders worldwide in 2020.”  In addition, “females were more affected than males, and younger people, especially those aged 20–24 years, were more affected than older adults.”

Not all people with mental health disorders respond well to traditional pharmaceutical and psychological treatments.  In fact, 30-40% of people with depression do not find sufficient relief with pharmacological or psychological treatment.  In response, the American Society for Nutrition (ASN) has fostered research into the link between nutrition and mental health for many years.  Moreover, these studies point the way to the role nutrition could play in maintaining good mental health as well as managing mental health disorders.  Below are highlights of original research studies and reviews published in the four ASN Journals that are leading to a better understanding of nutrition and mental health.

The Effect of a Mediterranean Diet on the Symptoms of Depression in Young Males (the “AMMEND: A Mediterranean Diet in MEN with Depression” Study): A Randomized Controlled Trial, The American Journal of Clinical Nutrition, April 2022

ASN member Jessica Bayes et al. conducted a 12-week randomized controlled trial to assess the effect of a Mediterranean diet in treating moderate to severe depression among 72 males, aged 18 to 25.  The participants, who had all been diagnosed with major depressive disorder, were divided into two groups: a diet intervention group and a control group.  The diet intervention group attended a 60-minute nutritional counseling appointment conducted by a clinical nutritionist who offered personalized dietary advice, goal setting, and mindful eating strategies to support adherence to the Mediterranean diet.  They were also provided information on serving sizes, sample meal plans, recipes, dining-out options, and a daily online diet history survey.  In contrast, participants in the control group attended “befriending” support sessions in which researchers discussed neutral topics of interest such as movies, sports, and hobbies.  Befriending support was chosen for its ability to control for factors that can confound randomized controlled trial results.  At the conclusion of the study, the authors determined that the diet intervention group experienced “significant improvements in depressive symptoms with no observed side effects.”  Specifically, the authors observed a mean reduction of 20.6 points on the Beck Depression Inventory Scale—Version II among the diet intervention group compared to a reduction of 6.2 points for the control group.

Chronic Stress and Unhealthy Dietary Behaviors among Low-Income African-American Female Caregivers, Current Developments in Nutrition, March 2020

Working with data collected over four years from the Detroit Dental Health Project, Sungwoo Lim et al., assessed the association between chronic stress and unhealthy dietary behaviors among 912 low-income African-American caregivers in Detroit, Michigan.  The average caregiver was 28 years old, raising two children.  Approximately half of the caregivers had a household income of less than $10,000 and did not have high school degrees.  Sixty-six percent of the caregivers reported that they experienced discrimination a few times per month or more.  Twenty-five percent of the caregivers reported an unhealthy dietary pattern characterized by an excess intake of high fatty foods and soda.  The authors believe that this unhealthy dietary pattern was “significantly associated with chronic stress,” as caregivers with chronic stress were more than twice as likely to consume an unhealthy diet.  Moreover, “almost 41% of this association was explained by an indirect pathway through depressive symptoms.”  In summary, the authors believe their research “provides evidence for developing a more targeted intervention to promote healthy dietary behaviors among chronically stressed minority caregivers.”

Persistent Food Insecurity Is Associated with Adverse Mental Health among Women Living with or at Risk of HIV in the United States, The Journal of Nutrition, February 2019

Emily L. Tuthill et al. investigated the association between food insecurity and depression among women participating in the Women’s Interagency HIV Study, a prospective cohort study of women at risk of or living with HIV in the United States.  The 2,551 study participants, with a mean age of 48, completed 6 semiannual assessments on food security and mental health.  Using multiple regression analysis, the authors estimated the association between these variables.  The study findings indicate that “food insecurity, especially when persistent, was associated with more depressive symptoms, greater risk of probable depression, and poor mental well-being among HIV-infected and at-risk women.”  Specifically, women with persistent food insecurity had a 6.86-point higher depression score than women with intermittent or no food insecurity, based on the Center for Epidemiologic Studies–Depression scale, which rates depressive symptoms on a scale from 0 to 60.  The authors call for the “development of multilevel programs and intervention strategies that are guided by a syndemic orientation…to optimize the health of HIV-infected and at-risk women.”

The Role of the Gut Microbiota in Dietary Interventions for Depression and Anxiety, Advances in Nutrition, March 2020

Nutritional scientists have been investigating diet and mood as well as the microbiome-gut-brain axis, which examines the influence of gut microbiota on neurobiology and behavior, in an effort to develop treatment strategies for mental health disorders that could complement traditional pharmaceutical and psychological strategies.  According to ASN member Tracey L. K. Bear et al. “because diet is a large influencer of the gut microbiota composition and function, it is likely that changes in the gut microbiota contribute to how diet (whole diet and individual components of diet) may affect depression and anxiety.”  The authors of this review further note that “limited research in this area is sometimes contradictory, and mostly in rodents, but does show a pattern of results indicating that the gut microbiota may play a significant role and should be considered in dietary intervention studies.”  The authors also believe there may be critical windows of development during which the gut microbiota have more effect on mental health, such as during early life, adolescence, and gestation.

As these studies suggest, there is a bidirectional relationship between nutrition and mental health: just as nutrition can affect mental health, mental health can affect nutrition.  We invite you to explore the full ASN Journals collection to learn more about nutrition and mental health to support your own research or clinical practice.  Key word searches using terms such as “depression,” “anxiety,” or “mental health” will lead you to an array of on-point original research studies and reviews.