Written by Tracy McDonough, RD, MScA

Current evidence suggests that diet quality may be a modifiable risk factor for mental health conditions. The relationship between diet and mental well-being is complex, however a relatively new field of study, nutritional psychiatry, aims to understand this relationship.  Current hypotheses on how diet impacts mental health include:

  1. Oxidative stress: Oxidative stress occurs in the body when free radicals cause damage to our body cells. Some free radicals are formed from normal body processes while other free radicals come from pollutants such as cigarette smoke. Antioxidants protect your cells from the damage caused by free radicals. Studies have shown that those living with certain mental conditions, such as depression, have higher levels of oxidative stress markers and lower levels of antioxidants. The exact relationship between mental health and oxidative stress requires more research to be well understood. When it comes to nutrition, however, it is well known that vegetables and fruit are rich in antioxidants, which protect the body against oxidative stress.
  2. Inflammation: Chronic, low-grade inflammation has been implicated in the development of certain mental conditions. Poor diets are known to be one of the numerous causes of inflammation. Diets higher in vegetables and fruit, as well as  healthy fats found in nuts, seeds and fish, have been shown to be associated with lower levels of inflammation.
  3.  Brain-gut-microbiome relationship: There is a complex, multi-directional relationship between the microorganisms that live in the intestinal tract, our diets, and mental health. Diet changes can modify the gut microbiome, while changes in the gut microbiome have been associated with various mental health outcomes.

What dietary patterns are associated with better mental health outcomes?

Diets rich in vegetables, fruit, whole grains, nuts, seeds, and fish, have been shown to reduce the risk of depression. Conversely, diets high in processed, high-fat, high-sugar foods have been shown to be associated with common mental disorders such as anxiety and depression in adults and adolescents.

How can I make my diet more brain-healthy?

  1. Replace processed snacks like cookies and crackers with a handful of dry-roasted, unsalted almonds, walnuts or pumpkin seeds. A small handful goes a long way!
  2. Get creative with fish. Try a lemon dill topping for trout or salmon (find the recipe below!), or make baked fish cakes with canned light tuna.
  3. Make half your plate vegetables. Try to include a dark green vegetable, like spinach, broccoli or peas and an orange vegetable like carrots or yam, every day.
  4. Keep whole fruit out in a visible place, like your kitchen counter. You won’t have to think hard to grab it for a snack!
  5. Meal plan. If you want to make any change to your diet, write out how this will be reflected in your meals and snacks throughout the week.