Dr. Roach: The microbiome is still somewhat of a mystery
Dear Dr. Roach: I have struggled with IBS and GERD since I was a small child. I have had multiple gastroscopies and have been on countless medications over the years for my issues. I’ve followed every diet and lifestyle change that my doctor has suggested, with, at best, moderate results.
Recently, a friend of mine suggested having my gut flora screened by a private company for analysis. This company takes your results and suggests a prebiotic regimen for you to help improve your gut’s microbiome. However, these tests are expensive, and I’m leery about spending $200 or more on a test kit that might not be as valuable as these companies claim.
The reviews online seem mixed, with some sources raving their efficacy and other sources saying these tests are limited in scope and of dubious value. What is your opinion on at-home private gut flora screening? Is it worth doing?
Dear N.E.: There is great excitement about the microbiome (the term for the “suite” of thousands of bacterial species in your intestine), but still a great deal of uncertainty. Experts estimate 40% of the genes identified in the microbiome have unknown function. There is not a consensus about what makes a “healthy” microbiome or an “unhealthy” one. It’s also not clear that an “unhealthy” result from your microbiome testing is the cause of, or the result of, intestinal disease. It is also very unclear that trying to manipulate a specific microbiome result through diet or probiotics leads to better outcomes than general healthy diet advice.
I rely on evidence, and the evidence that your $200 on testing will lead you to better health is not strong enough for me to recommend them at this time.
Dear Dr. Roach: My recent DEXA scan said I had a 19% chance of a major fracture within the next 10 years. Does that mean that I have an 81% chance of not having a major fracture?
Dear MEH.: Yes, that’s exactly what it means, but you should realize that after the 10 years, your risk will continue to go up. If you are one of the lucky 81% who does not get a hip fracture, you have a substantially higher chance in the following years to get a major fracture.
Most authorities recommend treatment when the risk of major osteoporotic fracture exceeds 20%, but not everyone will choose therapy at that level. The higher the risk, the more benefit a person will get from treatment, which involves diet, exercise, vitamin D, and sometimes medication. Treatment reduces the risk of fracture. In women with very low bone density, for every 100 women who took the medicine for three years, six did not get fractures who otherwise would have.
All medicines have downsides, and bisphosphonate drugs (the most common class of medicines used; Fosamax is one) increase the risk of several problems, including osteonecrosis of the jaw. These medicines should only be used when there is a clear benefit outweighing the risk, and the 20% threshold is one commonly used guideline.
Readers may email questions to ToYourGoodHealth@med.cornell.edu.