While many are aware of the connection between nutritional deficiency and physical illness, few grasp the connection between nutritional status and mental health. To illustrate the connection, consider several points made in a study from the Indian Journal of Psychiatry regarding each macronutrient:
CARBOHYDRATES - We know that when we eat carbs, they break down to sugar in the blood. This triggers the release of insulin, a hormone that helps blood sugar enter cells to be used for energy. Did you know that it also simultaneously triggers the entry of tryptophan into the brain, which can affect neurotransmitter levels? Someone on a low carbohydrate diet may be more susceptible to a mental disorder since carbohdryate-rich foods trigger the release of feel-good brain chemicals (serotonin and tryptophan). Also, someone who chooses more high glycemic foods (sugary foods, junk foods, sweets) will likely have a more temporary effect as opposed to the moderate, but lasting effect of low glycemic foods (such as whole grains, vegetables, fruits).
PROTEINS - Adequate protein intake is also essential since many neurotransmitters in the brain are manufactured from amino acids. For example, the feel-good neurotransmitter dopamine is made from the amino aicd tyrosine. Serotonin is made from tryptophan.
FATS - Did you know the brain is one of the organs with the greatest levels of fats? According to one estimate, gray matter is 50% fatty acids. About 33% of those fatty acids are from omega-3 fatty acids. Our bodies do not manufacture omega-3 fatty acids; they must come from our diet. Clearly, there is an important connection here between the macronutrient content of our diet and our mental health. Can the same be said of micronutrients?
VITAMINS - Consider vitamin B12. Adolescents with just a borderline blood level of vitamin B12 deficiency already show signs of changes in their brain function. When it comes to folate, clinicians have observed that patients with depression tend to have about 25% lower blood folate levels. In fact, folate supplementation has been shown to enhance the effectiveness of antidepressants.
MINERALS - The mineral iodine produced by the thyroid hormone is necessary for energy production in brain cells. Iron is required in order for the body to manufacture neurotransmitters and to oxygenate brain cells. Zinc can protect brain cells from oxidation.
THE BRAIN ON A NUTRIENT-POOR DIET
Another way a nutrient-poor diet can negatively impact brain function is by causing oxidative stress. Oxidative stress is damage caused by free radicals and reactive oxygen species. Oxidative stress can damage proteins, DNA, lipids (fats) in cells and organs, and mitochondria (a structure in cells that helps make energy for the brain to use in order to properly function).
The body has an antioxidant defense system to keep free radicals under control. However, a nutrient poor diet is one way these defense mechanisms can be overwhelmed.
A diet rich in nutrient-dense foods can supply needed food sources of antioxidants, including vitamin C, vitamin E, selenium, zinc, carotenoids, and more.
We now have a growing body of evidence that food and nutrition has an important role in mental health. Our next article will highlight some key foods that can help with one of the most common mental health disorders - anxiety.
References
Rao, T. S., Asha, M. R., Ramesh, B. N., & Rao, K. S. (2008). Understanding nutrition, depression and mental illnesses. Indian journal of psychiatry, 50(2), 77–82. doi:10.4103/0019-5545.42391
Bourre JM. Effect of nutrients (in food) on the structure and function of the nervous system: Update on dietary requirements for brain, Part 1: Micronutrients. J Nutr Health Aging. 2006;10:377–85
Coppen A, Bailey J. Enhancement of the antidepressant action of fluoxetine by folic acid: A randomized placebo controlled trial. J Affect Disord. 2000;60:121–30
Kaplan BJ, Rucklidge JJ, Romijn A, McLeod K. The emerging field of nutritional mental health: inflammation the microbiome, oxidative stress, and mitochondrial function. Clin Psychol Sci. 2015;3(6):1-17.