Dear Doctor: I’m 55 years old and am going through menopause. My grandmother had osteoporosis and so does my mother, so I’m worried. My dad read that probiotics can help, which sounds a little nutty. What on earth do a bunch of bacteria have to do with your bones?
Dear Reader: Although our skeletons have taken on their final size and shape once we reach adulthood, bones are living tissue continuously undergoing change. This occurs in a process known as remodeling, which is cellular activity in which old bone is removed and new bone grows in its place. Remodeling continues throughout our lifetimes and, (fun fact) in the process, most of the adult skeleton is replaced by new growth every decade. However, as we age, the removal of bone happens more quickly than replacement. Other factors — like hormonal changes that come with menopause, being sedentary, inadequate diet, certain medical conditions and smoking — are also associated with a decrease in bone mass and strength.
This net loss of skeletal mass, known as osteoporosis, results in such structural abnormalities as increased porosity and thinning of the bones, which make them weaker and more fragile. People with osteoporosis are at increased risk of stooped posture, loss of overall height, fractured or collapsed vertebrae, and fractures or breaks due to even a minor fall.
Although there is no cure at this time, medications, hormone therapy and some lifestyle changes have been shown to slow the rate of bone loss and to lower the risk of fracture. But now — and maybe this is what your dad is referring to — a new study puts forth the possibility that certain probiotic supplements may help balance the bone loss/bone growth equation in people with osteoporosis. According to the results of the study, which were published in June in the Journal of Internal Medicine, the bacterium Lactobacillus reuteri reduced bone loss in older women diagnosed with low bone mineral density.
Researchers measured the bone density of 90 women ages 75 to 80, all of them in good health but with low bone mineral density. The women were then randomly assigned to two groups. One group took a twice-daily supplement of freeze-dried Lactobacillus reuteri, which is a strain of lactic acid bacteria. The other group was given a placebo. None of the women knew which group they had been assigned to. After a year, the bone density in the shins of all of the study participants was measured again. It turned out that the women taking the probiotic supplement experienced half as much bone loss during that year as did the women in the placebo group. And while that’s a rather remarkable outcome, the authors of the study have a few words of caution. First, since this is the first human study of its kind, the data set is quite small. And second, the specific reasons behind the outcome of the study are not yet understood.
Still, the results are promising enough to ensure new and expanded studies. They add to both the interest in and the promise of the gut microbiome as a potential therapeutic target.
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Eve Glazier, M.D., MBA, is an internist and associate professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and assistant professor of medicine at UCLA Health.
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