# Section 16.1 Nutrition and Mental Health

Introduction to Depression
Depression is a mental disorder known for decreased mood, appetite, interest in pleasurable activities, and increased anxiety and sadness. Per year, depression affects about 14.8 million Americans over the age of 18 (“Depression Statistics” n.d.). There is some research suggesting that a healthy diet including exercise and increases in certain nutrients can decrease the effects of depression in adults. Conversely, it has been shown that consuming unhealthy diet laden with processed and refined foods was more likely to encourage depressive symptoms (Zeratsky 2015). Nutrition has the possibility of affecting onset, duration, and severity of depression. General dietary intake for Americans and many Asian countries is deficient in a large number of omega-3 fatty acids, vitamins, and minerals. A common theme in diets of sufferers of mental illnesses is a severe deficiency of these nutrients. Many different studies have been conducted on the effectiveness of using diet to treat depression, varying between the addition or removal of certain foods from the diet (Rao 2008).
Depression and Omega-3 Fatty Acids
Some studies focus specifically on the addition of fish to the diet, which increases the amount of n-3 polyunsaturated fatty acids (n-3 PUFAs), commonly known as omega-3s, present in the diet (Li 2015). The n-3 polyunsaturated fatty acids provided from fish are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and are sometimes referred to as ‘marine omega-3s’. Omega-3s are an extremely important factor in the body, participating in the regulation of blood clotting through the formation of hormones, artery contraction and relaxation, and inflammation, as well as interact with cells that regulate genetic function (“Omega-3” n.d.). Over time, the consumption of omega-3 fatty acids has declined and reported depression has increased. While this may only reveal correlation and not causation, there are many ways a diet rich in PUFAs could decrease depressive symptoms. One theory suggests that the conversion of EPA to various chemicals such as leukotrienes and prostaglandins may cause the antidepressant effect, while another states that the effect of DHA and EPA on brain cell signal transduction may be the reason. Despite the fact that one particular theory has not been proven to result in mood-elevation, many studies have shown that consumption of a dietary supplement is an effective treatment (Lakhan 2008). A study published in September 2015 used previous studies involving the correlations between fish consumption and depression and subsequent meta-analysis to determine whether or not there is meaningful evidence to support fish in treatment of depressive disorder. The study pooled 26 separate studies researching the connection between fish consumption and depression and concluded that high fish consumption could reduce the risk of depression (Li 2015).
Depression and Folate
Other studies have suggested folate as a possible treatment for depression. Simon Young, PHD and professor in the Department of Psychiatry at McGill University wrote on how the common theory that serotonin levels play a large role in mood regulation. In his research, he mentions the low ratio of studies on folate deficiency in relation to serotonin production. Due to the generally poor diet of sufferers of depression, folate deficiency is present in one third of patients. In most studies of the subject, neuropsychiatric disorders suggest a correlation between low serotonin levels and folate deficiency. Folate plays a role in the conversion of homocysteine to methionine after demethylating SAM-e (S-adenosylmethionine). SAM-e acts as an antidepressant in humans that increases levels of serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) in cerebrospinal fluid (Young). Overall, there are a few different routes to take to treat or supplement treatment of depression. Even if the treatment doesn’t work for a particular patient, a healthier diet can improve quality of life in other aspects.
1. Depression Statistics. (n.d.). Retrieved November 3, 2015, from http://www.dbsalliance.org/site/PageServer?pagename=education_statistics_depression
2. Lakhan, S., & Vieira, K. (2008). Nutritional Therapies for Mental Disorders. Nutrition Journal, 91-108. doi:10.1186/1475-2891-7-2
3. Li, F., Liu, X., & Zhang, D. (2015). Fish consumption and risk of depression: A meta-analysis. Journal of Epidemiology and Community Health. doi:10.1136/jech-2015-206278
5. Rao, T., Asha, M., Ramesh, B., & Rao, K. (2008). Understanding nutrition, depression and mental illnesses. Indian Journal of Psychiatry, 50(2), 77-82. doi:10.4103/0019-5545.42391
6. Young, S. (2007). Folate and depression-a neglected problem. Journal of Psychiatry and Neuroscience, 80-82. Retrieved November 6, 2015 </syntaxhighlight>
7. Zeratsky, K. (2015, March 11). Depression (major depressive disorder). Retrieved November 12, 2015