Copyright realclearscience
The term "probiotic" has a health halo around it, which is why you find the word slapped on all sorts of packaged foods particularly yogurt. "Probiotic" has become synonymous with "healthy." But is this link warranted? While there is evidence that probiotics can help resolve gut troubles, if you are generally happy with the function of your gut, there's actually good reason to avoid them. That's because probiotics often work, in that they can alter the composition of the gut microbiome. As many as 100 trillion bacteria inhabit your digestive system, collectively forming a community of sorts. If this community is functioning well, your gut will generally feel good. Introducing as many as 500 billion bacteria from a serving of probiotic yogurt could disrupt that balance. If these novel microbes don't play nice with your resident microbes, a functional gut could turn dysfunctional, especially if that yogurt becomes a dietary staple. "With a thousand or so different bacterial species able to live in the human gut, almost any number of stable microbiome communities are possible. With probiotics potentially causing lifelong consequences, therefore, much more needs to be done to understand individual variation something to bear in mind when you come across simplistic claims," Daniel M. Davis wrote in his new book Self-Defense: A Myth-Busting Guide to Good Health. Davis is the Head of Life Sciences and a Professor of Immunology at Imperial College London. Davis notes that probiotics can be helpful in bringing a 'broken' gut back into balance. There's even early evidence that they can augment the immune system, but this can be detrimental or beneficial. "In helping or hindering our fight with an infection this could easily go either way," he wrote. "Some symptoms of infection come about from the immune system itself overreacting, in which case dampening immune activity may help, but of course we dont want the immune system entirely switched off if dangerous germs need to be fought. Achieving this balance is delicate, and its still not obvious when probiotics help." So despite their burnished reputation, probiotics aren't always salubrious. If you and your gut currently get along, it's probably best not to mess with that relationship by introducing foreign bacteria. If your gut has been acting up, however, eating a probiotic food or supplement might just set it straight.
