Sleep hormone to strengthen bones?

New insight into the relationship between circadian rhythms and bone degeneration could mean that hope for osteoporosis prevention may lie in an unlikely source: melatonin. A study led by Faleh Tamimi, a professor at McGill's School of Dentistry in Montreal, found that supplemental doses of the naturally occurring hormone increased bone strength in elderly rats. Well known to regulate circadian rhythms, melatonin may inhibit the activity of osteoclasts, nocturnal bone cells that spur the breakdown process. "As we age, we sleep less well, which means that the osteoclasts are more active," says Tamimi. "This tends to speed up the process of bone breakdown." In the study, twenty 22-month-old male rats were accommodated at the University of Madrid and given melatonin supplements diluted in their drinking water. After 10 weeks, or approximately six human years, bone density and bone strength tests revealed increased volume and density in the test group and little difference in the control group. Despite positive results, Tamimi says more testing is necessary to determine whether supplemental doses of the sleep hormone are preventing bone breakdown or reversing it. "Until there is more research as well as clinical trials to determine how exactly the melatonin is working, we can't recommend that people with osteoporosis go ahead and simply take melatonin supplements," says Tamimi. Melatonin is produced by the endocrine gland in the brain. Upon passage to receptor cells, it provokes sleep by lowering the body temperature. Considered a natural sleep aid, melatonin is available over-the-counter in North America, by means of prescription in several European countries and not at all in others. Tamimi says she has applied for more funding to pursue the research.