Strong bones with melatonin

Old rats receiving supplements of melatonin have stronger bones, a new study shows. This confirms previous studies that have shown this hormone to have a positive effect on bone mass. Other studies also suggest that the optimal melatonin dosage for sleep problems is not necessarily high.

In the new study, a group of rats in an age corresponding to 60 year old people was randomly divided into two groups. One group was given melatonin in their drinking water in a high-dose of 10 mg/kg a day for 10 weeks, which corresponds to six human years. The second group served as the control group receiving plain water.

Results

At the end of the study the rats had their femur analyzed. The melatonin-treated rats had higher bone volume, and they had better data for the markers that reflect a healthy skeletal muscle. Both the trabecular structure, that is the sponge-like structure of the bone's interior was thicker and also the cortical thickness of the bone was greater compared to the control group. The researchers also found a higher bone stiffness, increased flexibility and a considerable increase in the absolute maximum load that the bones could carry without being damaged, compared to controls.

Bone tissue is renewed all the time because it is constantly being built up and broken down. At night, it is built up by a type of cells called osteoblasts, and in the daytime it is broken down by an other type of bone cells called osteoclasts. As we get older and sleep less, the activity of the osteoclasts exceeds that of the osteoblasts.

Many features of melatonin

Melatonin affects a range of functions in the bone marrow, among other things, it regulates the osteoblasts and stem cells in the connective tissue as well as a number of other factors affecting bone formation. Melatonin is best known for controlling the body's circadian rhythm, but is also involved in regulating our blood pressure, core temperature and immune system and it may play a role in our aging process.

Human Studies

A meta-analysis using data from 17 different melatonin studies, including 15 with healthy people whose only health problem was insomnia have shown that melatonin supplements produced a significant reduction of sleep onset latency by 3.9 minutes. A normal latency is 15 to 20 minutes. Sleep efficiency was improved by 3.1% and sleep duration increased by 13.7 minutes.

The studies done over the years have used melatonin in very different dosage ranging from 0.3 mg to 10 mg. In two surveys 50 and 80 mg were given, which is an unusually high dosage.

Refs.

Tresguerres IF, et al. Melatonin dietary supplement as an anti-aging therapy for age-related bone loss. Rejuvenation Res. 2014;17(4):341-6.
Brzezinski A, et al. Effects of exogenous melatonin on sleep: a meta-analysis. Sleep Med Rev. 2005;9(1):41-50.