(NaturalNews) A recent study carried out by researchers from Henry Ford Hospital in Detroit and Foundation for Research Support of the State of Sao Paulo has revealed that melatonin, a hormone which regulates the body's sleep-wake cycle, could help slow the growth of certain types of breast cancer tumors.
Published online in PLoS One, the study suggested that melatonin could inhibit tumor growth and cell production plus block new blood vessels in ER-negative breast cancer models from forming.
Melatonin is a hormone naturally made by the pineal gland, an endocrine gland in the brain. Production of melatonin takes place in the dark and is inhibited by light. Melatonin is also available in supplemental form.
Angiogenesis is the formation of new blood vessels, and one strategy used in slowing the spread of cancer is by blocking this process. For the study, the researchers looked at how melatonin affected angiogenesis in ER-negative breast cancer - they analyzed the association both in vitro and in vivo using mice.
The study team found that the tumors in the mice which were given melatonin for three weeks became significantly smaller and had less vascular growth, while the average tumor volume of the mice not given melatonin increased significantly. The in vitro studies revealed similar findings. In addition, the treated mice displayed excessive movement but neither aggressive behavior nor irritability. They also did not experience lethargy or weight loss.
"These early stage research results with the melatonin drug in a triple-negative breast cancer animal models achieved in our lab has not been seen anywhere else," said Adarsh Shankar, a research assistant in the Department of Radiology at Henry Ford Hospital and a co-author of the study.
Melatonin lowered prostate cancer risk
The anti-cancer effects of melatonin was also revealed in another study recently presented at the AACR-Prostate Cancer Foundation Conference on Advances in Prostate Cancer Research, which showed that higher levels of the hormone could lower the risk of developing advanced prostate caner.
"We found that men who had higher levels of melatonin had a 75 percent reduced risk for developing advanced prostate cancer compared with men who had lower levels of melatonin," said Sarah C Markt, M.P.H, from the Harvard School of Public Health in Boston.
Markt further discussed the importance of a good night's sleep and healthy sleep-wake habits. "Sleep loss and other factors can influence the amount of melatonin secretion or block it altogether, and health problems associated with low melatonin, disrupted sleep, and/or disruption of the circadian rhythm are broad, including a potential risk factor for cancer," she also said.
"Our results require replication, but support the public health implication of the importance of maintaining a stable light-dark and sleep-wake cycle," she added.
Night shifts raised breast cancer risk
Indeed, another study published online in Occupational and Environmental Medicine in 2013 revealed that working night shifts for 30 years or more doubled breast cancer risk.
Researchers had looked at 1,134 women with breast cancer and another 1,179 without the condition in Canada. Earlier similar studies had only covered nurses, while this study included women of different occupational backgrounds.
Although other factors such as sleep disturbance, vitamin D levels and lifestyle variations could have been implicated, melatonin is too important to ignore.
Other than its role in sleep-wake cycle regulation, melatonin is also a potent free-radical scavenger and wide-spectrum antioxidant. And a good sleep at night in darkness (as much as possible) would help the body produce more of this important hormone. Exposure to natural light during the day is also said to help improve melatonin production at night.