Proper brain function is dependent on good nutrition. Omega-3 fatty acids, B vitamins, and zinc are all key nutrients for brain tissue. Vitamin B12, folate, and vitamin B6 are involved in production of neurotransmitters, and zinc has antioxidant effects in the brain.1-7 The omega-3 fatty acids DHA and EPA are important for the structure of brain cell membranes.8,9 Inadequate levels of each of these nutrients have been linked to a greater risk of depression.1,10-13
Protection against oxidative stress makes plant food-derived antioxidants beneficial for the brain. Plus, many phytochemicals have anti-inflammatory and other non-antioxidant functions that may also enhance brain health.14-18
In contrast, consumption of fast food has a dose-dependent association with likelihood of depression, and greater consumption of commercial baked goods (muffins, donuts, etc.) is also linked to 38 percent increase in depression risk.19
A new study investigated whether improving the diets of young adults with symptoms of depression could improve those symptoms.20 Men and women age 17-35 were surveyed, and those with moderate to severe depression symptoms and high sugar and saturated fat intake were invited to participate.
Half of the participants were asked to follow a diet that included 5 servings of vegetables daily, plus whole grains, legumes, fruits, nuts and seeds, turmeric, and cinnamon. They were also instructed to reduce sugars, other refined carbohydrates, processed meats, and sweetened beverages. However, the intervention diet was not quite up to the standards of a Nutritarian diet, as lean meats, eggs, unsweetened dairy products, fish, and olive oil were also permitted. The other group was given no dietary instructions, just asked to continue their regular diets and return again after 3 weeks for follow-up.
Importantly, the researchers were able to validate that the diet change group increased their intake of phytochemical-rich vegetables and fruit by using skin spectrophotometry. This light-based measurement responds to skin “yellowness” from the level of carotenoids in the skin, which is determined by carotenoid-rich vegetable and fruit intake.
Before and after the dietary intervention, the participants completed surveys rating their frequency and severity of depression symptoms. Participants were contacted again by phone three months later for another survey. Depression scores decreased in the diet intervention group between baseline and 3 weeks but stayed the same in the control group. The improvement in depression scores improved proportionally to increases in fruit and vegetable intake measured by skin carotenoid scores. There were also improvements in measures of stress and anxiety.
After three months, about 80 percent of the diet change group said they had maintained at least some aspects of the diet; the diet change group’s depression scores remained similar to their scores at the three-week follow up, and lower than their baseline scores.19 Three weeks of small improvements – eating more vegetables and fruits and reducing high-glycemic refined carbohydrates and processed meats – set the participants on a course to making longer-term dietary improvements and maintaining a lower level of depression symptoms. To learn more about how food affects the brain, it is important to read my book Fast Food Genocide.
A Nutritarian diet rich in green vegetables, berries, beans, nuts, etc. promotes brain health, but may be low in low B12, zinc, and long-chain omega-3 fatty acids. I recommend supplementing with these nutrients. Visit the Personalized Vitamin Advisor to learn more about my supplement recommendations.
Kennedy DO. B Vitamins and the Brain: Mechanisms, Dose and Efficacy-A Review. Nutrients 2016, 8.
Office of Dietary Supplements, National Institutes of Health. Dietary Supplement Fact Sheet: Folate.
Miller AL. The methylation, neurotransmitter, and antioxidant connections between folate and depression. Alternative Medicine Review 2008, 13:216-226.
Ng TP, Feng L, Niti M, Kua EH, Yap KB. Folate, vitamin B12, homocysteine, and depressive symptoms in a population sample of older Chinese adults. J Am Geriatr Soc 2009, 57:871-876.
Sachdev PS, Parslow RA, Lux O, Salonikas C, Wen W, Naidoo D, Christensen H, Jorm AF. Relationship of homocysteine, folic acid and vitamin B12 with depression in a middle-aged community sample. Psychol Med 2005, 35:529-538.
Watanabe H, Ishida S, Konno Y, Matsumoto M, Nomachi S, Masaki K, Okayama H, Nagai Y. Impact of dietary folate intake on depressive symptoms in young women of reproductive age. J Midwifery Womens Health 2012, 57:43-48.
Gower-Winter SD, Levenson CW. Zinc in the central nervous system: From molecules to behavior. Biofactors 2012, 38:186-193.
Yurko-Mauro K. Cognitive and cardiovascular benefits of docosahexaenoic acid in aging and cognitive decline. Curr Alzheimer Res 2010, 7:190-196.
Cederholm T, Salem N, Jr., Palmblad J. Omega-3 fatty acids in the prevention of cognitive decline in humans. Adv Nutr 2013, 4:672-676.
Kim JM, Stewart R, Kim SW, Yang SJ, Shin IS, Yoon JS. Predictive value of folate, vitamin B12 and homocysteine levels in late-life depression. Br J Psychiatry 2008, 192:268-274.
Petridou ET, Kousoulis AA, Michelakos T, Papathoma P, Dessypris N, Papadopoulos FC, Stefanadis C. Folate and B12 serum levels in association with depression in the aged: a systematic review and meta-analysis. Aging Ment Health 2016, 20:965-973.
Swardfager W, Herrmann N, Mazereeuw G, Goldberger K, Harimoto T, Lanctot KL. Zinc in depression: a meta-analysis. Biol Psychiatry 2013, 74:872-878.
Office of Dietary Supplements, National Institutes of Health. Dietary Supplement Fact Sheet: Vitamin B12 [http://ods.od.nih.gov/factsheets/VitaminB12/]
Tsuboi H, Shimoi K, Kinae N, Oguni I, Hori R, Kobayashi F. Depressive symptoms are independently correlated with lipid peroxidation in a female population: comparison with vitamins and carotenoids. J Psychosom Res 2004, 56:53-58.
Dias GP, Cavegn N, Nix A, do Nascimento Bevilaqua MC, Stangl D, Zainuddin MS, Nardi AE, Gardino PF, Thuret S. The role of dietary polyphenols on adult hippocampal neurogenesis: molecular mechanisms and behavioural effects on depression and anxiety. Oxid Med Cell Longev 2012, 2012:541971.
Nabavi SM, Daglia M, Braidy N, Nabavi SF. Natural products, micronutrients, and nutraceuticals for the treatment of depression: A short review. Nutr Neurosci 2017, 20:180-194.
Hritcu L, Ionita R, Postu PA, Gupta GK, Turkez H, Lima TC, Carvalho CUS, de Sousa DP. Antidepressant Flavonoids and Their Relationship with Oxidative Stress. Oxid Med Cell Longev 2017, 2017:5762172.
Spencer JP. Flavonoids and brain health: multiple effects underpinned by common mechanisms. Genes Nutr 2009, 4:243-250.
Francis HM, Stevenson RJ, Chambers JR, Gupta D, Newey B, Lim CK. A brief diet intervention can reduce symptoms of depression in young adults - A randomised controlled trial. PLoS One 2019, 14:e0222768.