Successful Aging: A Neuroscientist Explores the Power and Potential of Our Lives

by Daniel J. Levitin

Melatonin is a naturally occurring hormone in the body, secreted by the pineal gland during the dark hours of the day, typically a couple of hours before bedtime. It is also produced in other parts of the body. In the retina it is believed to have protective effects on photoreceptors. In bone marrow, it functions as a scavenger of free radicals and enhances immune function, reducing oxidative damage and protecting against iron overload and deterioration in these highly vulnerable cells. In the gastrointestinal tract, melatonin heals and protects against disorders and is being used experimentally as a treatment for gastric cancer, reflux esophagitis, peptic ulcers, ulcerative colitis, and intestinal ischemia/reperfusion. Melatonin is also widely found in the plant kingdom, where it regulates day-night bio-cycles and acts as a scavenger of free radicals. In tomatoes, for example, it helps to protect the components of photosynthesis. In peas and red cabbage that are grown in copper-contaminated soil it enhances their tolerance and survival rates. This makes melatonin a very old chemical compound that, through evolutionary history, found expanded functionality in mammals.