The pineal gland in our brain produces melatonin, a hormone that helps regulate our circadian rhythm. It peaks at nighttime and is inhibited by the light of day. With darkness comes increasing levels of melatonin, bringing on lethargy, calm and sleep.
Studies have shown connections between the disruption of the circadian rhythm and increased risk of several types of cancer. Nightshift work, in particular, has been associated with increased risk of breast, endometrial, prostate and colorectal carcinoma. One study found that patients with shorter sleep durations had increased risk of colon polyps, the precursor to colon cancer. This study suggested that just a modest increase in sleep duration could have a substantial impact on the incidence of colorectal cancer.
THE POWER OF MELATONIN
In addition to facilitating sleep, melatonin enhances our immune system, decreases proliferation of cancer cells through a variety of mechanisms, prevents the spread of cancer cells and promotes cancer cell death.
Melatonin is not only produced in our brain, but in our retina and skin as well. The melatonin produced from the pineal gland is triggered by darkness, while the melatonin produced in our retina and skin is triggered by sun exposure, particularly near infrared light (NIR), which is greatest at dawn. Daytime melatonin is a powerful antioxidant that seeks out and destroys free radicals, byproducts of our metabolism, that can damage cells and ultimately lead to cancer. As little as 30 seconds of early morning sun on your retina can give you a flood of this protective daytime melatonin.
We spend approximately one-third of our life sleeping, and for good reason; good sleep is critical to good health overall, to include decreasing our risk of cancer. If you are not getting good sleep or feeling refreshed when you wake in the morning, discuss this issue with your health care provider.