Melatonin May Reduce the Risk of Prostate Cancer
Prostate Cancer: Melatonin May Reduce Its Incidence
Melatonin levels may influence the likelihood of developing prostate cancer. A high concentration of this hormone, known for its effects on regulating sleep-wake cycles, appears to reduce the risk of developing advanced prostate cancer by 75%.
This discovery was presented at the AACR-Prostate Cancer Foundation Conference on Advances in Prostate Cancer Research, held in San Diego from January 18 to 21, by Sarah Markt from the Harvard School of Public Health's Department of Epidemiology in Boston (USA).
The Actions of Melatonin
Melatonin is a hormone produced by the pineal gland, a small gland attached to the brain. The substance is synthesized during nighttime in response to darkness and is an important regulator of sleep-wake cycles. Besides its ability to regulate and improve sleep and mood, recent studies have shown that melatonin has many other properties, including a strong antioxidant power and the ability to regulate the cyclic production of other hormones, which in turn can influence the development of some types of cancer.
High Hormone Levels Protect Against Cancer
The study, conducted between 2002 and 2009, involved 928 Icelandic men. In the initial phase, urine samples were collected from each participant, and the concentration of 6-sulfatoxymelatonin—the main melatonin metabolite in urine—was measured. Additionally, each participant completed a questionnaire reporting any sleep difficulties. Data showed that 1 in 7 men had trouble falling asleep, 1 in 5 had trouble staying asleep, and 1 in 3 had taken medication to help sleep. In these subjects, urinary levels of 6-sulfatoxymelatonin were significantly lower than in those without sleep problems.
In the final phase of the research, it emerged that 111 of the 928 men developed prostate cancer, with 24 of them in an advanced stage of the disease. Men with urinary 6-sulfatoxymelatonin levels above average (17.14 ng/ml) showed a 31% lower risk of developing prostate cancer compared to those with levels below the average, while the risk of advanced-stage prostate cancer was reduced by as much as 75%.
The Importance of Circadian Rhythms
According to Sarah Markt and colleagues, sleep loss could reduce or completely block melatonin secretion, causing a series of dysfunctions. Health problems associated with low hormone levels, interrupted sleep, or circadian rhythm disruptions may include cancer.
As the researchers explained, it will be necessary to replicate these results and conduct further studies on the link between prostate cancer and melatonin, especially because melatonin levels are potentially modifiable. The study nevertheless highlights the importance of maintaining a stable light-dark and sleep-wake cycle for health.
Source: Sarah C. Markt “Urinary melatonin levels, sleep disruption, and risk of prostate cancer” AACR-Prostate Cancer Foundation Conference on Advances in Prostate Cancer Research. January 18-21, 2014. San Diego, CA
