Disordered sleep is a common and growing public health problem affecting 50-70 million people in the United States. While part of this is due to the business of modern life, there also appear to be other factors at play. At the same time, many Americans suffer from vitamin deficiencies due to poor diet and depleted food. Could these two issues be related? New chronobiology research on the link between vitamins and sleep suggest taking a multivitamin may be an important part of maintaining a healthy circadian rhythm.
Vitamin D: How the Sunlight Vitamin Regulates Circadian Rhythm
There has long been a suspected link between vitamin D and sleep, whereas many people who are deficient in this vitamin suffered from fatigue, insomnia and other indications of a circadian disorder. According to new studies, this is due to the role of vitamin D in the transcription of genes related to the circadian rhythm.
It is well known that sunlight is one of the major cues for our sleep-wake cycle. Previous research has shown that this is at least partially due to its effect on our hypothalamus, which cues the release of the sleep hormone in the absence of light cues from the eyes. However, vitamin D also may be part of the way that sunlight regulates the circadian rhythm. Vitamin D is synthesized when the ultraviolet rays of the sun interact with proteins in our skin cells. In turn, this vitamin D activates certain circadian genes. If you are not getting enough vitamin D, your body may be losing one of its ways of determining whether it is day or night and sleep disorders may ensue.
Seeing the Light
When it comes to vitamins and sleep, vitamin A appears to affect the circadian rhythm in a different but just as crucial way. Vitamin A is very important to maintaining good vision. This includes differentiating light from dark. As mentioned before, your eyes' perception of light is crucial to maintaining appropriate melatonin cycles and thus a healthy sleep-wake cycle. Without the ability to perceive light, your brain may release melatonin throughout the day, making you sleepy and fatigued. It ends up that the cells in your eyes that are responsible for perceiving light levels are especially dependent on vitamin A.
Even if you can see well, the parts of your eyes that perceive light levels, known as rhodopsins, may not be getting enough vitamin A to function correctly. In fact, night blindness and sleep disorders may be the first signs of a deficiency. If you have trouble sleeping, your diet may be a partial cause. This may be the first sign of a vitamin A deficiency that is having less-noticeable negative effects on your health.
B Vitamins and Sleep
B vitamins are well known for contributing to our energy levels. This is partially due to their role as cofactors in metabolic reactions. However, there may be a second reason that you feel tired when you don't get enough of this broad class of vitamins. Studies have found that people sleep better and have more REM sleep when given B vitamin supplements. We also know that B vitamins are important in the synthesis of hormones related to sleep and circadian rhythm, such as serotonin.
Vitamin B12 appears to have an especially important role in maintaining a healthy circadian rhythm. People who take a vitamin B12 supplement report better sleep and also have higher levels of melatonin metabolites in their urine at night. They also have decreased melatonin levels during the day, suggesting that B12 helps the body to maintain better control over their sleep-wake cycle. Taking a supplement of this vitamin has also been found to help treat jet lag and other common circadian disorders.
Getting the Vitamins You Need for a Healthy Circadian Rhythm
If you are interested in sleeping better—and who isn't?—getting enough vitamins may be an easy first step. Many people in the West have lower than optimal levels of nutrients, in part due to depleted soil. However, there are many supplements and multivitamins on the market that can help you to get enough of all of the nutrients you need. While it is important to eat a varied diet and to get as many vitamins as possible from your food, many people cannot get enough vitamins without taking a multivitamin. In addition, getting enough sunlight is important to metabolizing vitamin D, as well as to maintaining healthy melatonin levels. If you wear sunscreen and avoid direct sunlight to prevent skin cancer, an additional supplement of vitamin D may be necessary.
Many chronic diseases have been found to be linked to vitamin deficiencies. New research suggests that sleep disorders may also be caused by not getting the nutrients we need. Eating a healthy diet and taking supplements as needed to keep vitamin levels high is one of the most important things you can do to maintain optimal health and a healthy circadian rhythm.