A decrease in the diversity of good bacteria likely has to do with lifestyle changes that occur as people get older. “These were cross-sectional studies, so we haven’t tracked the human microbiome ‘through the years,’ and frankly that would be a difficult study to do,” says Dr. Bulsiewicz. “But I think we can all agree that as we age, it’s quite common for our diet to change. Some have dental issues or inadequate saliva and struggle to chew on fibrous foods. Others have an altered sense of smell or taste and as a result narrow their dietary preferences, reducing the diversity of their diets.”
Fortunately, there’s plenty that you can do in order to keep your gut bacteria flourishing. “We know from the American Gut Project that the single greatest predictor of a healthy gut microbiome is the diversity of plants in your diet,” he says. Besides making sure you’re eating a variety of plant-based foods, he says considering a probiotic supplement, limiting antibiotic use (when possible), and staying active are all linked to boosting gut health.
Most importantly, Dr. Bulsiewicz says this intel shouldn’t make you fearful. “Embrace aging,” he says. “It turns out that with the right outlook—and a healthy gut—getting older doesn’t have to be a downward slide and, in fact, can be quite the ride.”