What Is the Connection between Melatonin and Cancer?

Some scientific studies suggest that low levels of melatonin may be associated with an increased risk of cancer. Many researchers believe that identifying people with reduced levels of melatonin has helped to single out those with the highest risk of developing cancer. This link between melatonin and cancer has led researchers to investigate the possible use of melatonin to treat some forms of cancer as well.

Melatonin is a hormone which is secreted by the pineal gland at the base of the human brain. This hormone is closely related to the body’s internal clock that regulates daily cycles of sleep and alertness, known as the body's circadian rhythm. It also has an impact on mood and menstrual cycles, and acts as an antioxidant. Some researchers have raised concerns that this antioxidant property might inhibit the effectiveness of some chemotherapy treatments.

Researchers have discovered that certain cancer cells flourish when melatonin levels are reduced. Breast and prostate cancers in particular are more likely among patients with low levels of the hormone. They also found that when they raised the levels of melatonin, cancer growth frequently slowed.

Cancer treatment studies involving melatonin is promising, but not conclusive, and research continues. Pairing hormone treatment with chemotherapy has shown an increased effectiveness over chemotherapy alone in treating prostate and breast cancer. Improvements have been shown for both the survival rate and quality of life for many patients participating in the studies.

Production of melatonin can be affected by a number of factors. As people age, levels of this hormone decline gradually. Daily patterns of light and dark will also have an impact on hormone production, and people such as shift workers who spend nights in brightly lit areas are likely to have lower melatonin levels as a result. These people are also at an elevated risk of developing certain forms of cancer, leading researchers down new paths of research as they work to establish and study the link between melatonin and cancer.

Levels of the hormone can be increased in several ways, and people concerned about the link between melatonin and cancer can take steps to keep hormone production high. The body is able to produce the hormone itself, and production can be increased with regular patterns of bright light and darkness. Relaxation techniques such as meditation have also been shown to elevate levels of melatonin. The chemical can also be ingested in foods or as a dietary supplement. There is no recommended melatonin supplement dosage for treatment of cancer or any other disease or condition.