Inherent in all living organisms, nature’s circadian rhythm springs us into activity in the daytime and then into rest and restoration at night. And this circadian rhythm is attuned to the presence and absence of the sun, principally blue light.
Melatonin is critical to regulating the body’s circadian rhythm. When the sun goes down and it becomes dark, our eyes sense the absence of light and send a signal to the brain, which instructs the pineal gland to produce melatonin and put us to sleep.
Now in modern times, the incandescent light began humankind’s earliest assault on nature’s circadian rhythm. This has only worsened with the advent of television, computers, tablets, cell phones, gaming stations and whatever else produces light to interfere with our circadian rhythm. When the lights stay on, melatonin production is slowed or stopped.
Exposure to sunlight — at least 10 to 15 minutes a day is recommended — is also crucial to the production of vitamin D, which is found in very few foods but is important for sleep. Vitamin D is essential to bone health, and its deficiency can lead to brittle bones and other problems. But it has also been found to be essential to good sleep. A deficiency in vitamin D, according to researchers at Louisiana State University, has been linked to insomnia and even sleep apnea.
Other researchers examined data from the National Health and Nutrition Examination Survey (NHANES) to help explain what effect nutrient intake has on sleep quality and sleep symptoms. They found that low vitamin D levels led to difficulties staying asleep at night.
“Results from these nationally representative data indicate that sleep symptoms are associated with some dietary components,” the researchers concluded. “Vitamin D was associated with less difficulty maintaining sleep.”
How do you know if you have a vitamin D problem? You can have your vitamin D levels measured when you get your annual physical and take a blood test, but you will probably need to ask your doctor to include a vitamin D measurement and then follow up to see if your level is sufficient.
You can always take vitamin D supplements (check with your physician first), but you should take the supplements in the morning or no later than early afternoon. Since vitamin D is the sunshine vitamin, it can — like the sunlight or another light source — interfere with your body’s production of melatonin. Therefore, avoid taking vitamin D. in the evening.
If you have sleep issues, you should always discuss them first with your health care provider. If that consultation doesn’t yield the results you desire, then by all means seek out a physician specializing in sleep disorders.