Russell J. Reiter, a highly respected pineal gland researcher at the University of Texas Health Science Center in San Antonio, concluded in a 1994 article published in the Annals of the New York Academy of Sciences, "Melatonin may prove to be the most important free radical scavenger discovered to date."

Diseases that may be caused or aggravated by free radical damage include atherosclerosis (blockages in arteries), emphysema, cataracts, Parkinson's, Lou Gehrig's, other neurological diseases, and some forms of cancer.

Enhancing Immunity
A complicated interaction between our immune system, hormones, and nervous system allows our bodies to adapt to the external world and prevents us from coming down with infections. The pineal gland is intimately involved in regulating these systems. Receptors for melatonin have been found in lymphoid organs such as the thymus and spleen (Poon, 1994) and on white blood cells (Lopez-Gonzalez, 1993).

Melatonin is believed to enhance the immune system. Mice given melatonin had an increased response of immune globulins to antigens (Maestroni, 1988, Caroleo, 1994). The researchers speculate that vaccines may be more effective when given at the same time as melatonin supplements. Even when mice were given cortisol, a substance which depresses the immune system, additional melatonin counteracted the detrimental effects of the cortisol (Maestroni, 1986).

Melatonin counteracts the effects of stress on the immune system. When mice are restrained, their antibody production drops, the weight of their thymus gland decreases, and their resistance to viruses lessens. Evening administration of melatonin buffered them against the effects of stress (Maestroni, 1988). Many of the harmful effects on the immune system by stress are closely related to signs and symptoms of aging. In the elderly, the thymus gland shrinks and immunity is lowered. Since aging is associated with lower melatonin levels, melatonin replacement may have a role in improving immunity. The elderly are particularly susceptible to pneumonia, flu, and other infections.

Recent studies indicate that melatonin may restore the function of the thymus gland. The thymus gland is involved with the production and maturation of T lymphocytes. Melatonin stimulates the production of T lymphocytes in those who have a poorly functioning immune system (Maestroni, 1993). The mineral zinc is also thought to improve the functioning of the thymus gland. Melatonin is believed to facilitate the interaction of zinc with the thymus gland, allowing another pathway of immune enhancement (Mocchegiani, 1994).

Sze and colleagues found that giving mice melatonin for 2 weeks induced production of powerful virus and bacteria fighting substances such as interferon and interleukin-2.

We all know how great it feels the day after 8 hours of uninterrupted slumber. We feel younger, more energetic, almost forgetting that there is such a thing as "tired." For the elderly who have low melatonin levels, and toss and turn all night, supplementation could provide that refreshing rest so critical to well-being. In an article published in the November/December, 1994, issue of Psychosomatic Medicine, Michael Irwin, MD, and colleagues, at the San Diego Veterans Affairs Medical Center, studied 23 healthy men, ages 22 to 61. All spent 4 nights in a sleep laboratory. On the third night, volunteers were denied sleep between the hours of 3 am and 7 am. The majority of the subjects had substantially reduced activity of their white blood cells, specifically natural killer (NK) cells. NK cells help protect us from viruses and the abnormal growth of cancer cells.