Nutrition and the Brain: What We Know
With so many factors impacting mental health—from genetics to environment to age—it can be hard to tease out the impacts of diet and specific nutrients. Much of what’s known in this area stems from the nutrients required for the function and structure of the brain. For example, we know some of the most important nutrients for early brain development are protein, iron, folate, choline, iodine, long-chain polyunsaturated fatty acids, and vitamins A, B6, B12, and D—and that nutrition in the womb can impact brain function later on.
There are also some firmly established links between certain nutrient deficiencies and brain function. Vitamin B12 deficiency is associated with symptoms such as fatigue, poor memory, and depression, while iron deficiency in very young children is linked with attention and learning impairments. For children, it’s also been found in some clinical studies that the ketogenic diet (high in fat and low in carbs) can effectively treat symptoms of epilepsy.1
In addition, we know that antioxidants are important in protecting the brain against damage from free radicals, which are a natural byproduct of our metabolism. There is also a relationship between the brain and the gastrointestinal tract (the so-called brain-gut axis) that links the brain’s central nervous system to the gut’s enteric nervous system, where an estimated 90 to 95% of the body’s serotonin is produced. Serotonin is a key mood-regulating neurotransmitter.
Emerging Evidence on Nutrition for Mental Health
To uncover more about the possible benefits of nutrition on mental health, a new field called nutritional psychiatry has emerged. This new area of study focuses on nutrition to improve mood, enhance cognitive function, stave off cognitive decline, and reduce symptoms of certain neuropsychiatric conditions such as autism. A recent expert review of the findings to date gives us a look at the emerging science. 2
Some of the most compelling research shows evidence linking a Mediterranean-style diet, rich in whole grains, vegetables, fruits, nuts, olive oil, fish, and low-fat dairy, with a reduced risk of depression and anxiety. In older adults, it’s linked to cognitive improvements. This eating pattern has also been found to promote a diverse gut microbiota, which may be a contributing factor to positive effects on mood. Other studies show reduced depression symptoms with vitamin D supplementation, though it’s not clear how much is due to pre-existing vitamin D deficiency, which is quite common.