Sleep, Cancer And Marvelous Melatonin

Virtually every living thing, from single-celled amoebas to humans, produces melatonin—and for good reason. This hormone has two essential functions: It governs the sleep cycle and the biological rhythms associated with light and darkness, and it acts as an exceptionally powerful antioxidant that is particularly protective of DNA. In humans, melatonin is synthesized in the pineal gland, located front and center in the brain. This hormone is most intimately involved with sleep. Darkness signals its gradual release, and as levels build up, you begin to feel drowsy. Production peaks during the middle of the night and then begins to fall, tapering off as the sun rises. Problem is, sunset no longer means darkness as it did for most of human history. These days, as soon as night falls we turn on the lights, and we don’t turn them off until we go to bed. Bright lights dramatically reduce melatonin output, and this not only has detrimental effects on sleep—witness our epidemic of sleep disorders and the $4.5 billion we spend a year on sleeping pills—but it also increases risk of cancer and other serious health problems. Fortunately, you don’t have to wander around in the dark, go to bed at dusk, or take sleeping pills to get your melatonin cycle back on track and dramatically improve your sleep and overall health.

Melatonin supplements are another option for optimizing levels of this hormone. Taking 3 mg 30 minutes to an hour before bedtime has been shown to enhance feelings of sleepiness and reduce the time it takes to fall asleep. This supplement is also helpful with jetlag—which can wreak havoc on sleep cycles— because it helps reset your “body clock.” In addition, it is used by nightshift workers to improve sleep. Beyond facilitating sleep, studies reveal that supplemental melatonin is a good treatment for several medical conditions. A bedtime dose of 3 mg taken by migraine sufferers reduced headache frequency by around 50 percent, and migraines were of shorter duration and intensity. The same dose taken for two weeks by people with irritable bowel syndrome decreased abdominal pain. It’s also been shown to improve symptoms of seasonal affective disorder (SAD, or wintertime depression) when taken during the day. Additionally, melatonin has been demonstrated to lower nighttime blood pressure. Generally, the heart rate slows and blood pressure drops at least 10 percent at night before picking up again in the morning. People who do not experience this nocturnal dip in blood pressure are at increased risk of heart attack and cardiovascular death.

Study subjects taking 1 to 2.5 mg of melatonin before going to bed had marked reductions in nighttime hypertension and thus reduced their risk of heart attack and death. The Cancer Connection One of the most exciting areas of melatonin research is cancer. Whether it’s made in your pineal gland or taken in supplement form, melatonin is a potent antioxidant that protects cellular and mitochondrial DNA from mutations that give rise to, and propagate, cancer. Evidence to support the cancer-melatonin link has been building for decades. Women who work night shifts—which radically repress melatonin production—have about a 50 percent increased rate of breast cancer. Conversely, people who are blind typically have above-average levels of melatonin and significantly lower cancer rates.

A recent study showed that melatonin-depleted blood stimulates the growth of tumors in animals, while melatonin-rich blood reduces tumor growth. David Blask, the lead researcher of this study explained that melatonin puts breast tumors to sleep at night, but in artificial light the “cancer cells become insomniacs.”

Melatonin may help prevent cancer, but can it treat the disease? Canadian researchers conducted a meta-analysis of 10 studies involving patients with tumors of the breast, lung, brain, kidney, and skin who took 10 to 40 mg of melatonin a day. They concluded, “The substantial reduction in risk of death, low adverse events reported, and low costs related to this intervention suggest great potential for melatonin in treating cancer.”