Melatonin is a hormone manufactured from serotonin (our feel good hormone) and secreted by the pineal gland. Melatonin is well-known for its ability to control our sleep-wake cycles. It is secreted in darkness and suppressed by the light. Melatonin is also used to treat jetlag. Children have much higher melatonin levels than adults and, sadly, as we age these levels dramatically drop. Low levels of melatonin are also found in those with sleep and depressive disorders.
A 2003 study found that melatonin has an anti-estrogenic effect on estrogen-receptor positive breast cancer cells. Further research in the Journal of the National Cancer Institute found that nurses who worked rotating night shifts three nights per month for 15 years had a higher incidence of colorectal cancer. Earlier studies confirmed that night shift workers had higher rates of breast cancer. Another study in Gynecology and Obstetric Investigation looked at 68 women diagnosed with endometrial cancer and 70 with abnormal bleeding. The researchers compared the women’s blood melatonin levels and found that there was a six-fold lower difference in melatonin levels in those with endometrial cancer. Researchers believe that declining levels of melatonin are a risk factor for developing the disease.
The Importance of Vitamin B12
Studies show that B12 causes an earlier release of melatonin at night which resets the sleep-wake cycle. B12 acts directly on the pineal gland to provoke a faster release of melatonin.