Due to the fact that depression may relate to individuals to experiencing chronic low mood, motivation and feelings of sadness, many wrongly perceive it as being down to one or two causes – it is not just about attitude. The factors that lead to the onset of depression are vast and multifaceted.

Fighting depression can be tough. Adherence to treatment protocols can be challenging due to the low motivation that can be associated with depressed mood. Depression influences behaviour across every aspect of life, it can be relentless.

The ability to make small tweaks to one’s behaviours to improve things overall is really important. Modest lifestyle changes are most likely to lead to greater adherence and sustainability, providing the opportunity for longer term benefit. Small dietary changes are in this category, so I decided to do a literature search to see what the research says regarding nutritional intake and improving clinical depression, my findings were as follows.

First off I looked at what correlation studies could tell us about nutritional consumption and prevalence of depression (studies looking at populations seeing how common depression is in relation to what foods they eat). Often identifying factors that lead to the development of a condition or increased risk may not only help those undiagnosed avoid development, but can also identify the prognosis for those diagnosed providing a potential solution. Here are the findings (if you don’t want to read the science, skip to the end).

It will come as no surprise to many that the more vegetables someone eats, the less likely they are to have depression (Tsai et al, 2012).  Other studies support this evidence with suggestions that antioxidant intake and particularly dietary vitamin C consumption demonstrates strong inverse correlation with depression risk (Payne et al, 2012). Vitamin E intake and polyunsaturated fat consumption (See previous Omega 3 and depression blogs) may also inversely correlate to depression risk (German et al, 2011). Consumption of vegetables rich in folate such as greens may also be beneficial as deficiency is associated with the onset of depression, a lack of consumption of green leafy vegetables may lead to a deficiency in magnesium which has been also been correlated to onset depression (Serefko et al, 2013), although magnesium supplementation is not recommended due to potential for side effects such as diarrhoea.

It has also been demonstrated that consumption of fast foods and baked goods may be associated with development of clinical depression irrespective of activity levels, BMI and vegetable consumption (Sánchez-Villegas et al, 2012). Long term calorie surplus leading to the development of obesity also increases risk for depression onset (Keddie, 2011; Zhao et al, 2011).

Protein intake and the consumption of essential amino acids also appears important, tryptophan in particular appears to have an influence on development of depression in the first instance as well as relapse (Boojj et al, 2005). A lack of consumption of zinc through dietary protein sources such as meat and dairy may also correlate (Swardfager et al, 2013). Vitamin B found in these foods may also be influential (Levine et al, 1994; Mukai et al, 2014).

So what does all this suggest? Well the good news that consumption of a balanced diet will likely decrease the risk of depression. Ideally one would look to consume a diet rich in polyunsaturated fatty acids, vegetables (particularly leafy greens) and protein sources containing all essential amino acids all whilst maintaining the appropriate calorie balance to maintain a healthy BMI.

So what nutritional adaptations may be beneficial for individuals with depression? Check out blog number 2 for that information.

As always, it is best to check with a medical professional before making any dietary change intended for therapeutic purposes.

Jack Barton (Researcher, Rescon Ltd)

References
Booij, L., Haffmans, P. J., Spinhoven, P., & McNally, R. J. (2005). Acute tryptophan depletion as a model of depressive relapse Behavioural specificity and ethical considerations. The British Journal of Psychiatry, 187(2), 148-154
German, L., Kahana, C., Rosenfeld, V., Zabrowsky, I., Wiezer, Z., Fraser, D., & Shahar, D. R. (2011). Depressive symptoms are associated with food insufficiency and nutritional deficiencies in poor community-dwelling elderly people. The Journal of Nutrition, Health & Aging, 15(1), 3-8.
Keddie, A. M. (2011). Peer Reviewed: Associations Between Severe Obesity and Depression: Results From the National Health and Nutrition Examination Survey, 2005-2006. Preventing chronic Disease, 8(3).
Levine, J., Gonsalves, M., Babur, I., Stier, S., Elizur, A. et al. (1993) ‘Inositol 6 g daily may be effective in depression but not in schizophrenia.’ Human Psychopharmacology: Clinical and Experimental, 8(1), 49-53.
Mukai, T., Kishi, T., Matsuda, Y., & Iwata, N. (2014). A meta‐analysis of inositol for depression and anxiety disorders. Human Psychopharmacology: Clinical and Experimental, 29(1), 55-63.
Payne, M. E., Steck, S. E., George, R. R., & Steffens, D. C. (2012). Fruit, vegetable, and antioxidant intakes are lower in older adults with depression. Journal of the Academy of Nutrition and Dietetics, 112(12), 2022-2027.
Sánchez-Villegas, A., Toledo, E., de Irala, J., Ruiz-Canela, M., Pla-Vidal, J., & Martínez-González, M. A. (2012). Fast-food and commercial baked goods consumption and the risk of depression. Public Health Nutrition, 15(03), 424-432.
Serefko, A., Szopa, A., WlaŸ, P., Nowak, G., Radziwoñ-Zaleska, M. et al. (2013) ‘Magnesium in depression.’ Pharmacol Rep, 65(3), 547-54.
Swardfager, W., Herrmann, N., Mazereeuw, G., Goldberger, K., Harimoto, T. et al. (2013). ‘Zinc in depression: a meta-analysis.’ Biological Psychiatry, 74(12), 872-878.
Tsai, A. C., Chang, T. L., & Chi, S. H. (2012). Frequent consumption of vegetables predicts lower risk of depression in older Taiwanese–results of a prospective population-based study. Public Health Nutrition, 15(06), 1087-1092.
Zhao, G., Ford, E. S., Li, C., Tsai, J., Dhingra, S., & Balluz, L. S. (2011). Waist circumference, abdominal obesity, and depression among overweight and obese US adults: national health and nutrition examination survey 2005-2006. BMC Psychiatry, 11(1), 130.

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