Melatonin is a well-known sleep aid. It also has powerful applications in bone health. Melatonin may be especially useful for preventing osteoporosis in type 2 diabetics, although the dosage makes a big difference in results. (More is not better when it comes to melatonin for diabetic bone health.)
How does sleep influence bone health?
The relationship between melatonin and sleep is well known. The relationship between melatonin and bone health requires a little explanation. Consider these well-established relationships between sleep and osteoporosis:
- People who work at night and people who do shift work have lower bone mineral density and are more likely to have fractures and broken bones.
- In women who have gone through menopause, poor sleep is correlated with lower bone mineral density and more fractures.
- Older people who have insomnia are more likely to have osteoporosis.
- Fractures are also more common with sustained 24-hour exposure to light, such as is experienced in polar regions.
The cells that build up bone have a biological clock that makes them most active in the middle of the afternoon until about sundown on a 12-hour day (from about 1500 to 1800, that is, from 3 o’clock to 6 o’clock in the afternoon). The cells that break down bone are most active about 5 in the morning (0500).
When the eyes detect blue light, the hypothalamus in the brain sends out a signal that to release stress hormones to stop sleep and promote wakefulness. When someone eats tasty food at any time of day or night, the hypothalamus triggers the same process.
How do we know melatonin makes a difference in bone health?
Melatonin overrides the signals from light and food to let the hypothalamus-pituitary-adrenal axis shut down enough to stop pumping out stress hormones. By normalizing sleep patterns, melatonin ensures that bone-building osteoblasts are maximally active when the body is maximally stimulated by stress hormones and bone-destroying osteoclasts are maximally active when the body is not.
Several clinical trials have show than melatonin is helpful in osteoporosis:
- An Italian study tested the effectiveness of a combination of melatonin, strontium, vitamin D3, and vitamin K2 supplements given to post-menopausal women for a year. Women given melatonin and complementary supplements showed an average of 4.3 percent greater bone mineral density in the lumbar spine (lower backbone) and 2.2 greater bone mineral density in the neck of the femur. There was trend toward stronger hip bones but the results did not reach statistical significance.
- A Chinese study modeled the effects of melatonin on bone health in type 2 diabetes. High blood sugar levels activate the destruction of bone. Even without good blood sugar control, melatonin slows down this process by acting as a particularly strong antioxidant.
- A Danish study looked at the benefits of melatonin in improving postural stability, the ability to hold a pose, to stand still in various position. Women were given either 1 mg or 3 mg of melatonin or a placebo and tested for muscle strength, muscle flexibility, the ability to stand still with eyes open, the ability to stand still with eyes closed, and the ability to stand with one foot in front of but touching the other. Melatonin was significantly helpful in maintaining knee strength, and generally helpful with posture and preventing falls.
An advantage of using melatonin as an antioxidant for bone health over vitamins C and E, in addition to its benefits in regulating sleep patterns, is that higher doses of melatonin do not become pro-oxidant. In lower doses (under 1,000-2,000 mg) vitamin C is antioxidant, but higher doses have the opposite, bone-destructive effect.
What is the best way to take melatonin for healthy bones?
Melatonin is the overlooked supplement for treating osteoporosis. Most doctors will tell their patients to take calcium and vitamin D for osteoporosis. These are necessary, although taking more than 400 mg of calcium at a time or more than 1,000 mg of calcium per day offers no additional benefit. Similarly, massive doses of vitamin D, over 100,000 IU, sometimes make bone problems worse. There are similar rationales for the use of strontium, magnesium, vitamin D3, and vitamin K2. For all of these supplements, the recommended daily dosage is beneficial. Overdosing can be harmful. The same principle applies to melatonin. More is not necessarily better.
The Italian study got good results by giving 2 mg of melatonin at bedtime. This dosage is effective and it is also safe. Taking too much melatonin, enough melatonin to cause drowsiness the next day, might cause daytime drowsiness and actually increase the risk of falls and fractures. Just remember that a little is good and a lot is not to use melatonin effective for bone health.