Depression and anxiety, like many other chronic conditions, likely results from a complex interaction between genetics and environment. The question remains, how can what we eat affect our mood?
It continues to be studied that food can affect our mood. A longitudinal study publish in the International Journal of Environmental research and Public Healthy this February looked at 26,991 Canadian and immigrants and suggested a link between anxiety disorder and diet. "For those who consumed less than 3 sources of fruits and vegetables daily, there was at least at 24% higher odds of anxiety disorder diagnosis." This study prompted me to investigate this a little further. It left out of more of the "why?" than I was comfortable with.
Eating nutrient dense foods that contain optimal amounts of vitamins, minerals, and antioxidants nourishes the brain and protects it from oxidative stress produced when the body uses oxygen. This can damage cells within the brain and the rest of the body. Oxidative stress has been linked with depression, anxiety disorders and high anxiety levels.
"For those who consumed less than 3 sources of fruits and vegetables daily, there was at least at 24% higher odds of anxiety disorder diagnosis."
The body can produce some antioxidants on it's own, however a person's diet is also an important source of antioxidants. Foods such as fruits and vegetables provide many essential antioxidants in the form of vitamins, like A, C, and E, and minerals that the body cannot create on its own. It would make sense then why consuming less than three servings of fruits and vegetables daily were linked with higher rate of anxiety disorders. It should also be stated that in the above mentioned study that intake of one or more pastries daily, underweight BMI, and high levels of body fat (>26%) were associated with anxiety and depression as well.
Gut health and serotonin
It may not be all about the brain though. Serotonin, the "happy chemical", is a neurotransmitter that helps regulate sleep and appetite, mediate moods, and inhibit pain. While it is found in the brain, about 95% of your serotonin is produced in your gastrointestinal tract, that's your stomach and intestines. It is lined with millions of nerve cells. It can makes sense that the inner workings of your digestive system don’t just help you digest food, but also play a role in your emotions.
Serotonin levels in the brain get help from the amino acid, tryptophan. You might associate this with the turkey at Thanksgiving dinner. A 2016 review has shown that when a person follows a low-tryptophan diet, brain serotonin levels drop. Research is ongoing to determine how much tryptophan-containing foods can affect serotonin levels in the brain, however, a 2015 randomized crossover study showed that consuming more dietary tryptophan resulted in less depressive symptoms and decreased anxiety.
"About 95% of your serotonin is produced in your gastrointestinal tract, that's your stomach and intestines."
Tryptophan, which goes into making serotonin, is commonly found in foods that contain protein. Most people do associate protein with meat, however there are also many vegan and vegetarian sources:
Nuts & Seeds: pumpkin, chia, sesame, flax
Lamb, beef, pork
Again, the majority of serotonin in the body is made in the gut. A smaller amount is made in the brain. Tryptophan requires carbohydrates to be able to reach the brain and create serotonin, therefor foods that contain tryptophan are most effective if eaten with carbohydrates. In a society where many individuals overly restrict whole food groups and demonize individual foods, this can be problematic. Having Dietitians bring awareness to how carbohydrates fit into an individuals diet is important.
Overall gut health would appear to be essential at this point. It's important to state the role of probiotics which continually nourish the gut with "good bacteria" that help with digestion. While, some research may show a connection in whats being described as the gut-brain axis, it appears to be too early to actually tell what the role of probiotics in all of this is. It can hurt, though, to eat your fermented foods! Choose greek yogurt, kefir, and kimchi whenever you have the choice.
Other foods that can help!
Fruits and Vegetables: As noted, fruits and veg have been linked to higher levels of happiness. Focus on your fiber intake from these foods. Oranges, asparagus, mango, apricots, broccoli, carrots, blackberries, Brussels sprouts, and apricots are also great for soluble fiber.
Omega-3 Fatty Acids: This is the good stuff, found in fish. Low Omega-3 fatty acids have been correlated to depression and impulsivity. Plan to eat fish at least two times per week. Nuts and seeds can also provide a benefit, however not as strong as the above.
Chocolate: Chocolate may have properties that improve mood and even reduce tension. Choose real chocolate, greater than 70% cocoa.
Keeping it simple
It can't be overstated that singling out one specific food in hopes of improving your mood is not the answer. There is much more research to be broken down, showing links in lower rates of depression and anxiety with increased vitamin D intake, the Mediterranean diet, and less highly processed food.
The bottom line, choose to eat a diet that contains optimal protein and fiber rich foods, eat your colors, cook more at home, stay hydrated, sleep well, and move your body.
If you feel you could benefit from optimizing your diet for better health reach out to myself or another Dietitian you trust. If you feel you may be challenged with depression, anxiety, or other mood disorders - please seek support from a mental health professional. Nutrition is only part of the solution. Surround yourself with people who love and care for you.
You got this,
Karen M. Davison. Nutritional Factors, Physical Health and Immigrant Status Are Associated with Anxiety Disorders among Middle-Aged and Older Adults: Findings from Baseline Data of The Canadian Longitudinal Study on Aging (CLSA) Int. J. Environ. Res. Public Health2020,17(5), 1493
Singh M. Mood, food, and obesity. Frontiers in Psychology. 2014;5:925. doi:10.3389/fpsyg.2014.00925.
Mujcic R, J Oswald A. Evolution of Well-Being and Happiness After Increases in Consumption of Fruit and Vegetables. Am J Public Health. 2016 Aug;106(8):1504-10.