Hormones that affect sleep
The foods that make us less sleepy or more sleepy often contain nutrients that influence the body to produce certain hormones that control waking and sleep.
Tryptophan is one such amino acid important in the relationship between sleep and eating habits. Foods which contain tryptophan include eggs, lean meats and other proteins. In the body it is converted to a vitamin B, niacin, which has been known to foster sleep due to the serotonin it creates. Particularly after eating carbohydrates, the body produces insulin which eliminates all other amino acids except tryptophan.
The neurotransmitter serotonin serves a variety of functions in the body, primarily mood and well-being. But it also affects sleep. Serotonin triggers the part of the brain that is responsible for sleeping and waking. A serotonin receptor stimulating a certain area of the brain influences whether or not you sleep or wake up.
Melatonin is a hormone that is produced depending on what time of the day it is. Its production spikes when it is dark and lessens when there is more light. It also decreases with age, which is why older people tend to have problems with sleep. Melatonin is sold as a supplement to aid in sleep.