The food we eat affects the function of our brain in a variety of subtle ways. The most important connection of food and behavior comes from the processes of normal nutritional metabolism. What you eat directly and indirectly affects nerve chemicals, which in turn influence moods, energy levels, stress levels and sleep habits.
The neurotransmitter serotonin performs a variety of functions in the brain. High levels of serotonin increase tolerance to pain, decrease cravings for food, improve mood and enhance sleep. Low levels of the neurotransmitter result in increased sensitivity to pain, food cravings, depression, insomnia, aggressive behavior and poor body temperature regulation. Serotonin is manufactured in the brain from the amino acid tryptophan, along with folic acid and vitamins B6 and B12.
Food for Serotonin
Even though tryptophan is found in protein-rich foods, eating a protein-rich meal actually lowers tryptophan and serotonin levels in the brain, while eating foods rich in carbohydrates increases those levels. Sugar and refined starch triggers the quick release of insulin, which lowers blood levels of most large amino acids except tryptophan, thus allowing tryptophan to remain in the blood and enter the brain. Whole-grain starch triggers a slow and sustained release of insulin, which results in a gradual increase in serotonin levels without the rise and fall in blood-sugar levels experienced with sugar and refined starch. In addition to carbohydrates, consuming foods rich in folic acid and B vitamins will provide the body with the building blocks necessary for serotonin production.
Dopamine and Norepinephrine
Dopamine and norepinephrine (sometimes called noradrenaline) are neurotransmitters that are manufactures from tyrosine, an amino acid, as well as folic acid, magnesium and vitamin B12. A drop in the levels of these neurotransmitters produces feelings of depression and irritability. Consuming more tyrosine raises levels of these neurotransmitters and improves mood, increases alertness, alleviates stress and boosts mental functioning.
Food for Dopamine and Norepinephrine
Like tryptophan, tyrosine is abundant in protein-rich foods, but unlike tryptophan, tyrosine levels rise when you consume protein-rich meals. High levels of competing amino acids and low insulin lowers tryptophan but favors tyrosine. As a result, these two neurotransmitters are constantly at odds with each other in the human brain. For one to be high, the other must be low.
Choline, a fat-like substance, is unlike amino acids in that it has no competition for entry into the brain. The more choline is consumed, the more of it enters the brain and is used to produce the neurotransmitter acetylcholine, which is important in memory and general mental functioning. A decrease in acetylcholine levels is common with aging and may result in memory loss and reduced cognitive ability.
Food for Acetylcholine
You can boost brain levels of acetylcholine by consuming foods rich in choline, such as eggs and wheat germ, or by supplementing with nicotinamide, a form of niacin that enhances the concentration of choline in the brain.