Serotonin is responsible for carrying chemical transmitters between neurons, constricts smooth muscles and regulates various physiological processes, which include appetite and sleep-wake cycles. The neurotransmitter also plays an important role in stabilizing mood. Insufficient levels cause anxiety and depression. While some foods contain small amounts of serotonin, other foods contain the amino acid tryptophan, which is necessary for manufacturing the neurotransmitter.
However, merely eating foods containing high levels of tryptophan does not affect serotonin levels immediately. Many different amino acids compete to pass through the blood brain barrier to be used by neurons, and tryptophan often goes to the back of the line in terms of getting access. After consuming carbohydrates, the pancreas releases insulin, which escorts amino acids, fatty acids and glucose into body cells. But, insulin does not interact with tryptophan, so the path to the brain is then available for the amino acid.
Foods containing the highest levels of the amino acid include nuts and seeds, cheese, poultry and soy beans. Foods having a moderate amount of tryptophan include beef, lamb, pork and game meats along with fish, shellfish and whole grains. While meals commonly feature a combination of protein and carbohydrates, you have a better chance of tryptophan reaching the brain quicker when consuming carbohydrates without protein. On the other hand, alcohol, caffeine and diet sodas interfere with serotonin production.
Niacin or vitamin B6 is more important to body functions than tryptophan. If B6 levels drop, the body uses tryptophan and vitamin B3 to make more of the essential nutrient. If tryptophan levels in the blood become depleted and cannot make B6, serotonin and melatonin levels suffer along with mood. Vitamin B6 is also necessary to convert tryptophan into 5-HTP, which then transforms into serotonin. Foods having the highest niacin content include nuts, fish, organ meat and poultry. Vitamin B3, B6 and B12 are also available in B-complex supplements.
Magnesium and vitamin D are also vital to tryptophan conversion. While most people turn to dairy products for the nutrient, fish oil, oily fish, maitake and portabello mushrooms offer the highest levels of vitamin D. However, spending at least 15 minutes a day in the sun typically provides sufficient quantities of the nutrient.
It has long been known that exercise triggers dopamine in the brain. However, researchers from the National Institute for Health and Clinical Excellence in Great Britain found that participating in physical activity also increases the production, release and use of serotonin in the brain. Additionally, by getting routine exercise, tryptophan travels to the brain in larger quantities.