Strong and healthy circadian function is vital to good sleep and to overall good health. Circadian rhythms have a significant influence over sleep, working in concert with the body’s internal sleep drive to regulate periods of both rest and alertness. Circadian dysfunction often results in problems with sleep. The body’s circadian rhythms also help govern a broad range of other biological processes. In recent years, there’s been a wealth of evidence mounting to suggest that dysreguglation of circadian rhythms brings increased risk for illness and disease, including cardiovascular disease and metabolic disorders such as type 2 diabetes.
Recent research sheds new light on a relatively little understood factor in the body’s circadian functions: food intake. Researchers in Japan have studied cellular activity in mice to investigate the effects of dietary intake on circadian timing. Their results indicate that the hormone insulin may have a significant influence over the timing of circadian rhythms. Insulin, produced in the pancreas, plays an important role in metabolic functions. The hormone helps break down carbohydrates and fats, and enables glucose (blood sugar) to move from the bloodstream to cells throughout the body.
The idea that food can affect sleep isn’t new. We know that there exist a range of foods whose vitamins and minerals are helpful to sleep. Foods rich in calcium, potassium, and magnesium, as well as foods containing the amino acid tryptophan, are some of the most sleep-friendly dietary choices you can make. Sleep-boosting foods include many vegetables and fruits, nuts, beans, whole grain, dairy and lean protein. We also know that high-fat, high-sugar and heavily processed foods can interfere with sleep, particularly when eaten in frequently and in large quantities, and when eaten late at night.
In recent years, however, our understanding of the relationship between dietary intake and sleep has deepened, as we’ve learned more about the influence of food consumption over circadian rhythms.
When we think about influence over circadian function, we tend to think primarily about light. Circadian rhythms are aligned in 24-hour cycles with the solar night and day, and light—both natural and artificial—has a profound effect on our circadian function. But food intake also influences the timing of circadian rhythms. The mechanisms by which the timing and content of eating affects circadian function are much less thoroughly understood. This latest study provides some potentially important new detail about how food consumption—both the timing of eating and what kinds of foods we eat—may alter circadian rhythms via the production of insulin.
New details like this open up possible pathways for prevention and treatment of sleep problems as well as other health conditions that may be triggered by dysfunction in circadian rhythms. Much as we manage exposure to light in order to protect healthy sleep and circadian function, research like this offers further suggestion that we may also be able to manage dietary consumption to help keep circadian rhythms functioning properly.
Michael J. Breus, PhD
The Sleep Doctor™