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Melatonin

Melatonin is secreted by the pineal gland, a pea-sized entity located near the base of the brain. The pineal gland helps regulate the hypothalamus gland and influences the functioning of the thyroid, thymus, pancreas and adrenal glands. Melatonin is produced from the neurotransmitter serotonin.

Melatonin has many functions, including working as an antioxidant and helping to regulate circadian rhythms (the body's biological clock which regulates the sleep-wake cycles). It also has a positive influence on the immune system, and it may act as a prophylaxis against osteoporosis, as well as an effective adjunct in the fight against certain types of cancers.

The metabolic pathway by which melatonin is produced involves the neurotransmitter serotonin, a by-product of tryptophan, which is currently unavailable for over-the-counter sale in the US. Tryptophan is the least abundant of essential amino acids in normal diets, so it is likely that some individuals will have a deficiency. This imbalance directly effects the ability to experience a restful sleep, and could be positively effected by melatonin supplementation.

Melatonin also has applications in the prevention of jet-lag. Dr. Arendt, at the University of Surrey in England, observed that melatonin helped to re-synchronize the circadian rhythms of subjects flying through eight time zones (San Francisco to London). Those subjects who took melatonin 3 days before the flight, on the day of their departure and four days upon their return did not note any appreciable jet-lag.

Melatonin produces a substance called arginine vasotocin, which inhibits cortisol, a stress hormone produced by the adrenal glands. Insomniacs tend to have high nighttime levels of this agitating hormone, so inhibition of this hormone is another way melatonin promotes sleep. And the suppression of cortisol through the release of arginine vasotocin also bolsters the immune system. Through the suppression of cortisol, it helps to prevent the deterioration of lymphatic tissue, which is an integral part of the immune system.

Research has demonstrated melatonin's immune enhancing potential when administered to mice whose immune systems were challenged by either corticosteroids or a highly toxic virus (encephalomyocarditis) . Most of the mice who were pre-treated with melatonin showed a markedly higher survival rate than those who were not. Melatonin's immunoprotective capabilities could lend themselves well to conditions of psychogenic or environmental stress.

Additionally, melatonin may help prevent osteoporosis. There is evidence to suggest that menopause is associated with a substantial decline in melatonin because of impaired pineal functions due to calcification. During the early stages of menopause, the decline in melatonin production seems to be a contributing factor in the development of postmenopausal osteoporosis. Animal data indicates that melatonin is an integral component in calcium homeostasis, through its stimulatory effect on the pituitary and parathyroid glands - which inhibit calcitonin release and prostaglandin synthesis. Therefore, measuring the levels of melatonin in early menopause could indicate an impending osteoporotic condition, and taking melatonin could normalize levels and/or serve as a prophylaxis against osteoporosis.

Many diseases, including artherosclerosis, multiple sclerosis, muscular dystrophy, Parkinson's disease, emphysema, cataracts and autoimmune disorders, are directly related to free radicals (molecules or portions there of which contain one or more impaired electrons) that damage cells and organs. Among free radicals, the hydroxyl (OH2) oxygen-centered radical appears to be the most deleterious. Melatonin, through both in vivo and in vitro testing, has been demonstrated to be more effective than glutathione in scavenging this reactive molecule. In vivo tests utilizing safrole (a potent carcinogen from sassafras oil, that is known to damage DNA because of its ability to produce large numbers of oxygen-centered radicals) demonstrated a significant reduction in damaged hepatic DNA when compared to animals who were not pretreated with melatonin. In vitro, hydrogen peroxide exposed to ultraviolet light formed 6x less hydroxyl radicals when quenched by melatonin than by glutathione.

Melatonin also helps to prevent the proliferation of cancer cells. Studies show melatonin has a protective effect against breast cancer, and patients with brain metastases who were pretreated with melatonin also significantly improved their survival time, compared to those who were treated with steroids and anticonvulsant agents. However, it was observed that the inhibition was immediately reversed when its administration was discontinued.

Melatonin has been studied for the past three decades and has been administered at doses as high as 300mg a day without any adverse effects. It may cause increased grogginess upon arising when used for sleep disorders, but this is a temporary effect and can be prevented through regulation of the dose. Melatonin should only be used by children or adolescents under the advice of a physician. To prevent any disturbances in the circadian rhythms, melatonin should not be taken during the day, but only before retiring. Used in this way, melatonin can, at the very least, contribute to a good night's sleep, which itself promotes good health!

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