Aging Begins at 30

Over the Counter "Miracle Drug"

The hottest hormone in the health food store is called melatonin. The current hype in the lay press about melatonin is that it will make you stay young, give you better sex, better sleep, better health, and a longer life. Who wouldn't be interested in it? But is the hype true and what is melatonin anyway?

The ancients found a structure (later called a gland) at the center of the brain. It looked like an acorn so they gave it the Latin name pineal meaning acorn. Melatonin (derived from the Greek) is so named because it is related to black pigment cells that give our skin color and also to serotonin, a brain chemical messenger. In humans, the pineal develops until the seventh year when it is slightly larger than a pea. As melatonin is secreted into the blood by the pineal gland as a chemical messenger to organs at a distance, it fits the definition of a hormone. When it circulates, it affects the thyroid, adrenals, and gonads.

Melatonin is synthesized and excreted almost exclusively at night, triggered by the lack of light at sunset. That is, it has a circadian rhythm from circa (about) and dies (a day). Levels peak just before midnight. Is it related to diseases with arcadian rhythms such as asthma, myocardial infarction and rheumatoid arthritis? It was thought to be a biological clock set by the sun. Levels are high at puberty and decline toward old age. Levels of melatonin in the elderly are half those in young adults. Eighty-five percent is excreted as a byproduct in the urine and can be measured as an indicator of blood melatonin levels.

Because levels of melatonin are light activated, bright sunlight will lower natural levels with reciprocal nighttime high levels. Indoor lighting is less than 1/200th as effective as sunlight. Nerves have been found in animals that connect the eyes to the pineal and embryonically it is formed from the same germ plasma as the eyes.

The pineal develops until age seven when it is slightly larger than a pea. The onset of puberty appears to be triggered by changes in the blood melatonin level.

Biological clocks in each cell and each animal keep them in harmony with the rhythms of nature, especially day and night and the seasons. If a person is kept in an environment in the dark and out of touch with nature, they drift slowly out of phase with the natural world. The pineal gland and its secretion of melatonin enable the body to become tightly coupled to the master clock in the brain. Laboratory animals in all-light or all-dark environments can be "fooled" by melatonin administration to reset their clock. Treatment with melatonin improves the sleep-wake rhythm in blind subjects.

Melatonin has profound influences on the reproductive activity in seasonally breeding mammals. Melatonin is high in women with certain types of absent periods. It is linked with the suppression of reproductive function in animals. Some boys with delayed puberty have increased daytime melatonin. Precocious sexuality has been associated with low melatonin levels. Melatonin levels are raised in women with anorexia nervosa.

Mice treated with melatonin outlived those given a placebo by one third. Melatonin shields rats from certain types of cancer. In animals, immune responses are improved and pain tolerance is increased.

About 15 actions have been proposed for melatonin. It is claimed to induce sleep, to stimulate the immune system through the white blood cells, prevent age related diseases, help control cancer, tell the body what time it is, decrease clot formation in heart disease, prevent jet lag and weariness caused by changing shifts, prevent cataracts, treat glaucoma, treat or help treat depression, lighten dark skin in animals, and, if it brings animals into heat, will it boost your sex life or cure your infertility? There is no known lethal dose in laboratory animals so why not give it a try?

We can show its effect on jet lag and work shift changes, and possibly it is useful in helping patients with Alzheimer's disease and autism sleep at regular normal times. It may require a two or three month trial. Overall sleep quality is improved. Specifically it decreases awake time and time to fall asleep. REM sleep is not affected. Rapid transition through multiple time zones causes jet lag, which can be prevented by melatonin.

Melatonin was isolated in 1958 and was synthesized in the 1970s. Melatonin is sold as a food supplement, so it is not regulated in regard to effectiveness, purity, or poisonousness by the FDA. It could make you grow extra toes or kill you. Commercial melatonin comes from pineals or is synthesized. Impurities have been shown in some over the counter melatonin. You can buy this pig in a poke as pills, 150 for $10-$15. In controlled trials, about 10% of subjects have had side effects such as itching, headaches, morning grogginess, low sex drive, and evidence of abnormal liver function.

Caveat emptor: let the buyer beware. Remember if it sounds too good to be true, it probably is too good to be true. Can we separate the hype from science? What is probably true and usable? Clinical medicine is like faith; enough information for action without enough for total intellectual satisfaction. Where do we go from here?

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