Preventing Depression

A systematic review by O’Neill et al. (2022) examined 7 randomized controlled trials on the effect of different dietary interventions on depression in adults, and found fresh produce, wholegrains, low-fat dairy and lean protein to be beneficial, and processed and high-fat foods to be detrimental.  In their discussion they highlight a study by Lindseth et al. (2015) where adequate dietary tryptophan was found to be helpful for depression prevention, as well as one by Kontogianni et al. (2020) where a high-dietary polyphenol intervention resulted in lower measures of depression that the low-polyphenol control diet.

The high-tryptophan foods used in the Lindseth et al. (2015) study included mozzarella, soy, pumpkin seeds, and egg whites.  The meal plans for these 25 participants were calculated based on energy requirements, and provided the RDA for all nutrients.  Even the low-tryptophan diet provided the RDA for tryptophan, but the high-tryptophan diet provided twice the RDA for tryptophan (> 10 mg/kg body weight/d) .  Even though each participant consumed the high tryptophan diet for only 4 days and the low tryptophan diet for only 4 days, with two weeks in between, and none of them had been diagnosed as depressed at baseline, at the end of the low tryptophan diet they were close to scoring depressed on the validated Zung’s Self-Rating Depression Scale (SDS), but not at the end of the high tryptophan diet.  The authors caution that tryptophan supplements could have side effects if taken at high doses, which is one reason they used dietary sources in their study.

The Kontogianni et al. (2020) study did not use a cross-over design; after a four week wash-out where all 99 participants consumed a low-polyphenol diet, for the next 8 weeks they were randomized to either switch to a high-polyphenol diet or to continue the low-polyphenol diet.  The low-polyphenol diet was to include no more than two servings of fruits and vegetables per day, and berries and dark chocolate were not allowed.  The high-polyphenol diet included six or more servings of fruits and vegetables, with one being berries, plus 50 grams of dark chocolate per day.  Each participant was allowed to choose which fruits and vegetables they wanted delivered to their home.  At baseline, the participants were consuming an average of 2.7 servings of vegetables per day.  In the high-polyphenol group, scores on the Beck Depression Inventory-II (BDI-II) decreased by 66.6%, which is a clinically significant change, even though hypertensive participants had been recruited, so on average they were not considered to be depressed by their scores.  The authors list berries, grapes, apples and plums, cabbage, eggplant, onions, peppers, tea, coffee, red wine, fruit juices, seeds, nuts and dark chocolate as good sources of polyphenols.

Cheng et al. (2024) conducted a cross-sectional study of data from the National Health and Nutrition Examination Survey (NHANES) 2005–2018, and found that a carbohydrate intake of 45.3 % to 59.1 % of total calories was least associated with depression, while those with low-carbohydrate or high-carbohydrate diets were more likely to be depressed.  They also found that depression was less likely with higher protein intake.  Higher or lower fat intake was not more likely to be associated with depression, but the range of percentage of calories from fat was only 29%-39%.

Miki et al. (2019) found that Japanese workers who were not depressed at baseline were more likely to be depressed three years later the more days per week they tended to skip breakfast.  The authors suggest a couple mechanisms whereby skipping breakfast could lead to depression, although they note that the design of their study did not enable them to infer causality but only association.  For one thing, skipping breakfast could result in higher cortisol levels and increased hypothalamic-pituitary-adrenal activity.  Or, it could be disrupting their circadian rhythms, and leading to depression that way.

In a cross-sectional study, Ferriani et al. (2022) found that depression was associated with lower intakes of antioxidants and B vitamins.  For women this included vitamins A, E, B6 and B12, selenium, and zinc, while for men vitamin B12 was the only significant association. 

A systematic review by LaChance and Ramsey (2018) created a list of foods high in nutrients found to be helpful in the prevention of depression by the scientific literature- folate, iron, long-chain omega-3 fatty acids (EPA and DHA), magnesium, potassium, selenium, thiamine, vitamins A, B6, B12, and C, and zinc.  The foods at the top of the list were oysters, mussels, seafoods, organ meats, leafy greens, lettuces, peppers, and cruciferous vegetables.  Winter squash and strawberries also scored high. 

Ruangritchankul et al. (2023) found depression to be associated with low serum levels of zinc, and noted that beef, pork, fish, nuts, seeds and whole-grain cereals are good sources of zinc.  However causality cannot be inferred, and the authors suggest that managing depression could help to prevent low zinc levels rather than the other way around.  They also mention that the older participants had low dietary intake of zinc. 

References:

Cheng, Z., Fu, F., Lian, Y., Zhan, Z., & Zhang, W. (2024). Low-carbohydrate-diet score, dietary macronutrient intake, and depression among adults in the United States. Journal of Affective Disorders, 352, 125–132. 

Ferriani, L. O., Silva, D. A., Molina, M. D. C. B., Mill, J. G., Brunoni, A. R., da Fonseca, M. de J. M., Moreno, A. B., Benseñor, I. M., de Aguiar, O. B., Barreto, S. M., & Viana, M. C. (2022). Associations of depression and intake of antioxidants and vitamin B complex: Results of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). Journal of Affective Disorders, 297, 259–268. 

Kontogianni, M. D., Vijayakumar, A., Rooney, C., Noad, R. L., Appleton, K. M., McCarthy, D., Donnelly, M., Young, I. S., McKinley, M. C., McKeown, P. P., & Woodside, J. V. (2020). A High Polyphenol Diet Improves Psychological Well-Being: The Polyphenol Intervention Trial (PPhIT). Nutrients, 12(8). 

LaChance, L. R., & Ramsey, D. (2018). Antidepressant foods: An evidence-based nutrient profiling system for depression. World Journal of Psychiatry, 8(3), 97–104. 

Lindseth, G., Helland, B., & Caspers, J. (2015). The Effects of Dietary Tryptophan on Affective Disorders. Archives of Psychiatric Nursing, 29(2), 102–107. 

Miki, T., Eguchi, M., Kuwahara, K., Kochi, T., Akter, S., Kashino, I., Hu, H., Kurotani, K., Kabe, I., Kawakami, N., Nanri, A., & Mizoue, T. (2019). Breakfast consumption and the risk of depressive symptoms: The Furukawa Nutrition and Health Study. Psychiatry Research, 273, 551–558. 

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). 

Ruangritchankul, S., Sumananusorn, C., Sirivarasai, J., Monsuwan, W., & Sritara, P. (2023). Association between Dietary Zinc Intake, Serum Zinc Level and Multiple Comorbidities in Older Adults. Nutrients, 15(2).