Melatonin occurs naturally as a hormone that helps regulate the body’s circadian rhythms, but what role does melatonin play in aging?
What is Melatonin?
Melatonin is a hormone produced from the amino acid tryptophan within the pineal gland of the hypothalamus of the brain. It is secreted into the blood and cerebrospinal fluid and seems to have a role in regulating the circadian rhythms of the body. These circadian rhythms may include the sleep-wake cycle and variations in body temperature, blood pressure, and the release of hormones. It may be used to treat jet lag, insomnia, shift work sleep disorder, and circadian rhythm disorders such as advanced and delayed sleep phase syndrome.
How Melatonin Levels Change in Aging
The average levels of melatonin vary greatly throughout our lifetimes. Melatonin is first secreted when we are just three or four months old, which coincides with when we begin to sleep at night. After a rapid increase that peaks between 1 and 3 years of age, the levels fall back to a plateau that persists throughout adulthood. As we age, however, the levels begin to decline.
By the time we are 70 years old, our melatonin levels are only 25 percent of what they were when we were younger. It is thought that these changes may relate to the calcification of the pineal gland as we age, which results in a loss of its ability to secrete the hormone. It has been speculated that replacement of melatonin may be helpful to counteract some of the ill effects of aging.
Is Melatonin the Fountain of Youth?
Based on some small studies on rodents, it was thought that melatonin may be protective against aging. Unfortunately, melatonin is not the fountain of youth: there is no anti-aging effect in humans. It may be useful in improving sleep efficiency in aging-related insomnia, however, which might make you feel just a little bit more youthful.
Sources:
Anisimov, VN et al. “Dose-dependent effect of melatonin on life span and spontaneous tumor incidence in female SHR mice.” Exp Gerontol 2003; 38:449.
Kennaway, DJ et al. “Development of melatonin production in infants and the impact of prematurity.” J Clin Endocrinol Metab 1992; 75:367.
Pierpaoli, W et al. “Circadian melatonin and young-to-old pineal grafting postpone aging and maintain juvenile conditions of reproductive functions in mice and rats.” Exp Gerontol 1997; 32:587.
Waldhauser, F et al. “Fall in nocturnal serum melatonin during prepuberty and pubescence.” Lancet 1984; 1:362.
