Dear Dr. Roach: Your recent column regarding probiotics was very interesting. While I would think that following the Mediterranean diet is excellent advice, for folks like myself, with IBS, it isn't a totally doable thing. Therefore, the questions asked by the writer are important: "Does the number of bacteria matter more than the types listed on the container? Does one take them daily, for a brief time period, or for extended time periods?"
A: My column on healthy bacteria in the gut noted that a healthy diet, such as the Mediterranean diet, induces a change in the microbiome associated with better health outcomes. But P.J.S. is right that this diet isn't right for everyone.
I do not recommend probiotics for everybody. In fact, for people with no gut symptoms, probiotics are unnecessary. However, they have been shown to be useful in some gastrointestinal conditions, such as inflammatory bowel disease and irritable bowel syndrome.
There are no good studies to directly answer your question about type versus concentration of bacteria. However, my suspicion is that the type of bacteria is more likely to matter: Examples of probiotics that have some evidence showing improvement in IBS include Bifidobacterium infantis and Lactobacillus salivarius. Other species of the same bacterial genus also have shown benefit. My clinical experience with probiotics is that what works for one person may not work for another.
The trials using these probiotics generally lasted four to eight weeks. As the goal is to change the types of bacteria living in the gut, a general recommendation is taking them only four to eight weeks. At least one study showed that symptoms continued to improve a year after finishing the probiotics.
Dear Dr. Roach: I am a postmenopausal woman with osteoporosis (my T-score is -3.2) in my spine. I used alendronate, but stopped because it caused bone pain. I haven't been on any medication for a few months now, but I have started walking 40 minutes every day and I use weights. Also, I monitor my calcium and vitamin D carefully. My last bloodwork all came back good. My doctor would like me to try Tymlos. I can't find much information about it except that it hasn't been out long and may cause osteosarcoma. Do you know what the chance of this might be? A similar drug, Forteo, is not covered by my insurance, even though it has been around longer.
A: Abaloparatide (Tymlos) is an analog of parathyroid hormone. It works against osteoporosis by stimulating bone growth. This is different from the mechanism of alendronate (Fosamax) and related drugs; those work by preventing bone reabsorption.
Teriparatide (Forteo) indeed works the same way as Tymlos. During drug testing, teriparatide was found to increase the risk of a type of bone cancer, osteogenic sarcoma, in rats. Because of this, the Food and Drug Administration required a black-box warning, the agency's highest degree of caution. However, a study on women who have taken Forteo showed no cases of osteogenic sarcoma in the first seven years of the study, and only a handful of cases have ever been reported in people taking Forteo. In fact, the number of cases reported is less than would have been expected if there were no association between the drug and the cancer. It appears so far that Forteo does not increase risk for bone cancer, and there's no reason to expect that Tymlos will do so.