Melatonin is nature’s sleeping pill. It is secreted by the light sensitive pineal gland which regulates our biological clock and synchronizes our hormonal-immune network. Our level of melatonin rises with darkness and falls with light. According to Dr. Uzzi Reiss, in his book Natural Hormone Balance, a healthy pineal gland produces 2.5 milligrams of melatonin every twenty-four hours. Melatonin plays a central role in the natural aging processes of the body.
When pineal production begins to diminish, at around age 40, the decline sets off changes in the operation of the body’s cells. The physiology of the cell shifts from repair and rejuvenation to aging and degeneration. Recent studies are now showing that as our levels of melatonin sink, our chances for breast cancer rise. Many women with breast cancer have lower levels of melatonin than those without the disease.
Laboratory experiments indicate that lower levels of melatonin stimulate growth of breast cancer cells. Adding melatonin to these cells inhibits their growth.
Breast cancer and melatonin: studies and results According to a study at the Department of Physiology, Faculty of Science, University of Extremadura, Badajoz, Spain, published in Molecular and Cellular Biochemistry, Oct. 2005, melatonin increases the survival time of animals with untreated mammary tumors.
The aim of the study was to evaluate the therapeutic effect of melatonin on rats with advanced and untreated mammary tumors. Mammary tumors were chemically induced in rats. Following appearance of the tumors, the effect of melatonin was evaluated based on the survival time, tumor multiplicity, and tumor volume up until the death of the animals.
Additionally, the variations in prolactin, noradrenaline and adrenaline concentrations, and percentage of NK cells were evaluated after one month of the melatonin treatment. Results indicate that daily administration of melatonin increased significantly the survival time of tumor bearing animals compared to the control non-melatonin receiving rats.
However, the lengthened survival time did not correlate with changes in either tumor multiplicity or growth rates. Animals with mammary tumors exhibited increased levels of prolactin and catecholamine concentrations compared to the healthy animals. The administration of melatonin stabilized the hormone levels, returning them to the levels of the healthy animals.
Rats with mammary tumors also presented lower percentages of NK cells, however these levels were not increased with the administration of melatonin. Researchers concluded that melatonin is beneficial during advanced breast cancer. It increases survival time, perhaps by improving the homeostatic and neuroendocrine equilibrium which is imbalanced during advanced breast cancer.
As published in the International Journal of Cancer, January, 2006, researchers at the Department of Physiology and Pharmacology, School of Medicine, University of Cantabria, Santander, Spain, found that melatonin inhibits the growth of induced mammary tumors by decreasing the local biosynthesis of estrogens through the modulation of aromatase activity.
They note that melatonin inhibits the growth of breast cancer cells by interacting with estrogen-responsive pathways, effectively behaving as an anti-estrogenic hormone. They had previously described that melatonin reduces aromatase expression and activity in human breast cancer cells, thus modulating local estrogen biosynthesis.