Your brain also uses tryptophan, an essential amino acid you can only get from food, to make melatonin, Dr. St-Onge said. Tryptophan is notoriously abundant in turkey, but other sources like chicken, fish, cheese, sunflower seeds, tofu and white beans provide similar amounts. There is little research into whether consuming tryptophan-rich foods might improve sleep, Dr. St-Onge said, but small studies that have tested supplements or cereals containing the amino acid have suggested that there could be benefits.
Rather than focus on any one food or nutrient as the key to good sleep, however, it may be better to think about your diet as a whole, Dr. St-Onge said. When researchers scrutinize the eating and sleeping habits of people around the world, they notice that those who regularly consume more fruits and vegetables, complex carbohydrates like fiber, and healthy fats (from sources like salmon, olive oil and nuts) tend to sleep better than those who consume less of those foods and nutrients.
They’ve also found links between following a Mediterranean-style diet and lower risks of insomnia symptoms, like trouble falling asleep or waking during the night, said Arman Arab, a research fellow at Brigham and Women’s Hospital in Boston who led a recent meta-analysis on the topic.
Diets that prioritize fruits, vegetables, whole grains and other plant foods are rich in antioxidants and other compounds that tamp down inflammation, which has been associated with sleep disturbances, said Erica C. Jansen, a nutritional epidemiologist at the University of Michigan School of Public Health. They also contain folate, vitamin B6, zinc and magnesium, which your body needs to produce melatonin from tryptophan, Dr. St-Onge said.
But the studies that have found associations between certain diets and better sleep can’t prove cause and effect — they can only show correlations, Dr. Arab said.