Cancer

There is good evidence for photoperiod dependence and/or melatonin responsiveness in the initiation and evolution of certain cancers, particularly hormone-dependent cancers. Because of its powerful oncostatic effects and its estrogen-blocking ability, melatonin demonstrates particular promise in the treatment of breast cancer. Used in con-junction with tamoxifen to modulate cancer endocrine therapy, melatonin shows marked ability to modulate estrogen receptor expression and inhibit breast cancer cell growth.

Immune System

Melatonin has general stimulatory effects on immune system functions. One theory is that melatonin acts as an anti-stress hormone via the brain opioid system, with consequent up-regulation of the immune system.

Antioxidant Activity

Melatonin has both water and fat soluble properties, making it one of the only known antioxidants in nature that can protect all parts of a cell. Recent evidence suggests that melatonin plays a critical role in free radical scavenging activity. In fact, melatonin has been proven more powerful than both glutathione and mannitol in neutralizing hydroxyl radicals and may protect cell membranes more effectively than vitamin E. Remarkably, it is five hundred times more efficient at protecting cells from radiation than dimethylsulfoxide (DMSO).

Cardiovascular Disease

A decrease in melatonin causes increased nighttime sympathetic activity, which in turn appears to increase the risk for coronary disease. Lower levels of melatonin may act to increase circulating epinephrine and norepinephrine, which have been implicated in damage to blood vessel walls.

Ovulation and Pregnancy

Recently melatonin has stimulated the interest of researchers for its potential use as an oral contraceptive. One melatonin-based contraceptive is already undergoing Phase III clinical trials. Long term use of such a con-traceptive could reduce the risk of breast cancer by preventing the proliferation of epithelial breast cells caused by continuous ovulatory cycles.

“Melatonin may be the premier molecule to protect the organism from oxidative damage.” RJ Reiter

G U I D E L I N E S

Melatonin is an important neuroendocrine hormonal regulator that plays a significant role in reproductive health, sleep-wake cycles, mood, and body temperature. Melatonin is also a potent antioxidant that plays a critical role in free radical scavenging.