2021 Namey/Burnett Preventive Medicine Writing Award Submission
By Emily Bilyk, DO, PGY-1; Andrew Goodbred, MD; and Abby Rhoads, DO
; Saint Luke’s Anderson, Family Medicine Residency

In any given year, more than 17.3 million American adults—or about 7.1% of the U.S. population—aged 18 and older are affected by major depressive disorder (MDD) (National Institute of Mental Health, 2019). This does not account for the additional mental health fallout that has been seen in the face of the COVID-19 pandemic, with some studies estimating that the prevalence of depressive disorder in June 2020 was approximately four times that reported in the second quarter of 2019 (Czeisler, 2020).

People with MDD are more likely to suffer from physical illness and those with physical illnesses are more likely to suffer from MDD. Findings from meta-analyses of cohort studies show a modestly sized bidirectional association between depression and type 2 diabetes (Tabek, 2014). There are also findings that depression predicts greater major adverse cardiac event risk in patients with stable coronary artery disease (Frasure-Smith, 2007).

Depression is common among those with cancer, epilepsy, multiple sclerosis, stroke, Alzheimer’s disease, HIV/AIDS, Parkinson’s disease, Systemic lupus erythematosus and Rheumatoid arthritis (National Institute of Mental Health, 2015). The mainstays for treatment for MDD include cognitive behavioral therapy and antidepressant medications; however, we also have an underutilized opportunity to connect our patients with depressive symptoms to lifestyle modifications that have the potential to improve their mental health, especially in the area of nutrition.

While dietary guidance is highly individualized, with proper advice, we can provide our patients with the tools to improve both their physical and mental health through diet. This post is intended to review recommendations and evidence for dietary modification as a part of a comprehensive and holistic approach to the management of major depressive disorder. Additionally, strategies are offered to encourage patients to consider incorporating nutritious foods into their treatment plan.

Giving nutrition advice can be a bit of an ambiguous topic, so using data driven resources to educate patients is vital. One such resource is the 2015–2020 Dietary Guidelines for Americans. Key recommendations from this document include eating vegetables from all of the subgroups, including dark green, red, orange, legumes and starchy vegetables; and eating fruits—especially whole fruits (U.S. Department of Health and Human Services, 2015).

Other items included in this balanced diet include grains (at least half of which are whole grains), fat-free or low-fat dairy and a variety of protein foods and oils (U.S. Department of Health and Human Services, 2015). This healthy eating pattern limits saturated fats (<10% calories per day), trans fats, added sugars (<10% calories per day), sodium (<2300mg per day) and alcohol (U.S. Department of Health and Human Services, 2015).

The American College of Lifestyle Medicine recommends a whole food plant-based diet, which places similar emphasis on eating whole plants such as fruits, vegetables, whole grains, beans, nuts and seeds (Center for Nutrition Studies, 2017). This resource also is in line with avoiding artificial or processed foods, as well as those with added sugars or fats (Center for Nutrition Studies, 2017). This plan differs mainly in that it recommends the avoidance of animal products such as meat, fish and dairy, and requires supplementation with a B12 vitamin (Center for Nutrition Studies, 2017). Ultimately, these are just two evidence-based dietary plans and it is at the physician’s discretion to work with his or her patient to find healthful nutrition recommendations that will best serve his or her individual patient’s needs.

 While this general guidance is an excellent starting point to discuss nutrition with our patients, taking a closer look at the many journal articles that have explored this topic will be helpful additions to patient education. The Cambridge University Press published an article by the University of Navarra, in which the relationship between fast food consumption was compared to depression risk (​Sánc​hez-Villegas​, 2012). For this prospective study, consumption of fast food and pastries was assessed at baseline in a Spanish cohort of 8,964 patients (​Sánc​hez-Villegas​, 2012). Over the course of the study, with median follow-up at 6.2 years, a linear correlation for a higher risk of depression was found with the degree of fast food intake (​Sánc​hez-Villegas​, 2012). Consumption of fast food in the highest category was actually associated with a 40% higher risk of depression (​Sánc​hez-Villegas​, 2012). 

Another study evaluating the effects of fruit and vegetable consumption can be found in the American Journal of Public Health. The longitudinal food diaries of 12,384 randomly sampled Australian adults ​in the “Household, Income and Labour Dynamics in Australia Survey,” were compared to their life satisfaction scores, when controlled for changing incomes and personal life circumstances (Mujcic, 2016). Ultimately, increased fruit and vegetable consumption was associated with increased happiness (Mujcic, 2016). The benefit of eating up to eight portions of fruits and vegetables each day, was equal in size to the psychological gain seen when moving from unemployment to employment, with improvements occurring over the course of 24 months (Mujcic, 2016).

These studies provide us with some excellent insights but can be limited in that, as with most nutrition research, they are not randomized controlled trials and thus cannot account for causality in this association of poor diet with depression.

One study that addresses this well is in the American Journal of Health Promotion, known as “the GEICO study” (Agarwal, 2015). In this study, 10 corporate sites involved 292 participants who were either overweight or had previously received a diagnosis of type 2 diabetes and were randomized to receive either weekly instruction in following a vegan diet or no instruction for 18 weeks (Agarwal, 2015). Depression and anxiety were evaluated at the beginning and end of the study, using the Short Form-36 questionnaire (Agarwal, 2015). There was significant improvement in the study group versus controls in depression, anxiety and productivity scores (Agarwal, 2015). 

Incorporating balanced nutrition goals should help to both prevent and treat depression and to lessen the public health burden of this disease. However, taking this information from the journal articles to the clinics is a key and challenging task.

One excellent first step is to ask a patient to keep a food diary either in a physical journal, worksheet or on one of the available phone applications—many of which are free and designed for this purpose. In this way, both the patient and clinician can have a clearer idea of which areas they may be struggling in.

Writing a nutrition prescription for a specific goal that is agreed upon through motivational interviewing, is also an excellent tool. To reduce the amount of soda to one can per day—or to get at least one serving of fruits or vegetables with each meal—can be examples of specific, measurable and attainable goals. The power of framing this as a prescription from the doctor can increase the patient’s investment in working towards that goal.

Other important tools are to become well informed about any resources in the community that might work to provide free or discounted produce to people who otherwise might have limited access. It is important to be aware of the physical, financial, social and cultural barriers that might challenge our patient’s goals to pursue a more nutritious diet and to work with them to problem-solve meaningful solutions.

While the importance of appropriate therapeutic and pharmacologic treatment of major depressive disorder is paramount, improving the overall quality of nutrition in our communities will help to reduce the burden of depression and many other associated diseases on our communities and healthcare systems. In the words of Hippocrates, “Let food be thy medicine.”

Resources

  • Agarwal U, Mishra S, Xu J, Levin S, Gonzales J, Barnard ND. A multicenter randomized controlled trial of a nutrition intervention program in a multiethnic adult population in the corporate setting reduces depression and anxiety and improves quality of life: the GEICO study. Am J Health Promot. 2015 Mar-Apr;29(4):245-54. doi: 10.4278/ajhp.130218-QUAN-72. Epub 2014 Feb 13. PMID: 24524383.
  • Czeisler MÉ , Lane RI, Petrosky E, et al. Mental Health, Substance Use, and Suicidal Ideation During the COVID-19 Pandemic —United States, June 24–30, 2020. MMWR Morb Mortal Wkly Rep 2020;69:1049–1057. DOI: http://dx.doi.org/10.15585/mmwr.mm6932a1
  • Frasure-Smith N, Lespérance F. Depression and Anxiety as Predictors of 2-Year Cardiac Events in Patients With Stable Coronary Artery Disease. Arch Gen Psychiatry. 2008;65(1):62–71. doi:10.1001/archgenpsychiatry.2007.4
  • Mujcic R, J Oswald A. Evolution of Well-Being and Happiness After Increases in Consumption of Fruit and Vegetables. Am J Public Health. 2016 Aug;106(8):1504-10. doi: 10.2105/AJPH.2016.303260. PMID: 27400354; PMCID: PMC4940663.
  • Sanchez-Villegas, A., Toledo, E., De Irala, J., Ruiz-Canela, M., Pla-Vidal, J., & Martinez-Gonzalez, M. (2012). Fast-food and commercial baked goods consumption and the risk of depression. Public Health Nutrition, 15 (3), 424-432. doi:10.1017/S1368980011001856 
  • Tabak, A. G., Akbaraly, T. N., Batty, G. D., & Kivimaki, M. (2014). Depression and type 2 diabetes: a causal association? ​Lancet Diabetes Endocrinolgy, 2​ (3), 236-245. doi:10.1016/S2213-8587(13)70139-6

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