Diet and Mental Health

One in five American adults and one in six American youth suffer from mental illnesses every year. Mental illnesses have claimed their spot among the most common medical conditions worldwide. Studies in the new field of Nutritional Psychiatry have established a link between the quality of our diets and common mental disorders, offering a complementary solution to the treatment of mental illnesses.

Mental Illness has emerged as a severe public health crisis. Depression, specifically, leaves individuals unable to accomplish every-day tasks, it contributes to unemployment, substance abuse, and heightened risk of suicide. Additionally, the government and the health care system spend billions of dollars managing these illnesses every year, and with these staggering statistics, it’s evident that there is a need for new interventions to abate our mental health crisis. The small, but growing field of Nutritional Psychiatry strives to communicate that there is, in fact, a relationship between the kinds of food we eat and our mental health outcomes. While there’s no evidence that diet alone will prevent or cure common mental illnesses, experts have noted that diet is an important risk factor among other interrelated environmental and genetic factors.

Instead of thinking, “Is this food healthy?” or “is this food bad for me?” think of foods as mood enhancers or mood depressants. Good mood foods are colorful fruits and vegetables, nuts and seeds, high-quality proteins, and healthy fats. These types of nutrient-dense whole foods are high in vitamins, minerals, and antioxidants that feed and protect the brain. With the growing research that processed food can negatively impact our mental health,[5] we should begin asking ourselves, “Is this a good mood food?” and, “Is this food good for my brain?” Specifically, there is evidence that adopting a Mediterranean style diet can not only lower the risk of depression, but it can also improve general brain health.

The Mediterranean diet is just a traditional way of eating, and it’s said that those who follow other traditional diets, such as Japanese and Italian, are less likely to develop mental illnesses and chronic diseases as well. These diets are higher in fresh vegetables, fruits, olive oil, nuts, seeds, legumes, herbs and spices, unprocessed whole grains, lean cuts of meat, and fatty fish. In general, those who adhere to traditional diets avoid added sugar, processed meats, refined grains, and flours, all of which are staples of a western diet.

Healthy fats are an important piece of the Mediterranean diet, as well as other traditional diets. Omega-3 fatty acids are touted for improving cognitive function and general brain health, as they are anti-inflammatory and have neuroprotective properties. Those who follow traditional diets consume high-quality olive oils and wild-caught fatty fish, which are some of the most potent sources of omega-3’s in nature. It’s no wonder that the Mediterranean diet is linked with a lower risk of depression.[5] It’s important, however, to maintain a balance of omega-3 and omega-6 fatty acids. In our Western diet, we eat substantially more omega-6 fatty acids from industrially made vegetable oils such as corn and canola oils, which appear in almost every packaged product. This imbalance is incredibly damaging, causing excess inflammation in your body and your brain, which can lead to a decline in brain health.

The food we eat can directly affect the way that we feel, which is why nutritional psychiatry is an important intervention to consider in our chronically diseased, obese, and depressed society. How does food affect mood? The answer lies in serotonin production. Serotonin is a brain neurotransmitter that influences mood, appetite, sleep, memory, learning, and some social behavior. About 90% of serotonin is produced in your gastrointestinal tract (aka your gut), which is why your gut is often called your “second brain.” Your brain and your gut are in constant conversation. The gastrointestinal tract is made up of billions of bacteria that are critical to your health, as they protect the lining of your intestines to fight against bad bacteria. These good bacteria are responsible for lowering inflammation, optimizing nutrient absorption, improving immunity, and producing neurotransmitters, like serotonin. This is why keeping our gut health in check is beneficial for combating depressive symptoms, as well as many other illnesses. Incorporating a wide variety of healthy foods into your diet can promote the growth of good gut bacteria. Additionally, incorporating fermented foods (i.e, probiotic-rich foods) into your diet can help support an abundant microbiome. Highly processed foods will throw off your gut microbiome balance, as they diminish the growth of good bacteria. Furthermore, you need fiber content from fruits, vegetables, and unprocessed whole grains, to feed your good bacteria.

While depression and mental illnesses are linked to a number of different genetic and environmental factors, studies show that changes in nutritional behavior may be associated with a reduced risk of developing a mental illness. For general health, paying closer attention to how food affects your mood is a surefire way to increase happiness and energy levels on a day-to-day basis. Incorporating more colorful fruits and vegetables, high-quality proteins, healthy fats, whole grains, and reducing intake of added sugar, vegetable oils, and processed foods are basic ways to enhance cognitive function and to improve mood.

[1] “Mental Health By the Numbers.” NAMI: National Alliance on Mental Illness, Sept. 2019, https://www.nami.org/learn-more/mental-health-by-the-numbers.

[2] “Mental Health By the Numbers.”. 2019,

[3] Lai, Jun S., et al. “A Systematic Review and Meta-Analysis of Dietary Patterns and Depression in Community-Dwelling Adults.” The American Journal of Clinical Nutrition, vol. 99, no. 1, Jan. 2014, pp. 181–97. academic.oup.com, doi:10.3945/ajcn.113.069880.

[4] Publishing, Harvard Health. “Food and Mood: Is There a Connection?” Harvard Health, https://www.health.harvard.edu/mind-and-mood/food-and-mood-is-there-a-connection. Accessed 5 Nov. 2019.

[5]Sánchez-Villegas, Almudena, et al. “Fast-Food and Commercial Baked Goods Consumption and the Risk of Depression.” Public Health Nutrition, vol. 15, no. 3, Mar. 2012, pp. 424–32. Cambridge Core, doi:10.1017/S1368980011001856.

[6]MD, Eva Selhub. “Nutritional Psychiatry: Your Brain on Food.” Harvard Health Blog, 16 Nov. 2015, https://www.health.harvard.edu/blog/nutritional-psychiatry-your-brain-on-food-201511168626.

[7]“How to Optimize Your Omega-6 to Omega-3 Ratio.” Healthline, https://www.healthline.com/nutrition/optimize-omega-6-omega-3-ratio. Accessed 5 Nov. 2019.

[8]Serotonin and Depression: 9 Questions and Answers. https://www.webmd.com/depression/features/serotonin#1. Accessed 5 Nov. 2019.

[9]Microbes Help Produce Serotonin in Gut. https://www.caltech.edu/about/news/microbes-help-produce-serotonin-gut-46495. Accessed 5 Nov. 2019.