“Giving kids probiotic supplements helps set up their gut and immune health for life,” Lispki says. “It also counteracts the many rounds of antibiotics our kids are exposed to these days.” Here's her advice for babies up to a year old: Make a paste of Bifidobacteria infantis — typically the only probiotic babies are exposed to until they consume a wider variety of solid foods — and place it on their tongues. If you are breastfeeding, you can also simply take one or two capsules of the supplement yourself. For kids ages 1 to 4, try a supplement that contains Bifidobacteria infantis and Lactobacillus acidophilus, another common type of probiotic. “You can sprinkle it on their food,” Lipski suggests. Once kids reach age 4, they can take the same supplement you do.

Note: If you or your child begin taking supplements and experience an up-tick in digestive upset, it's likely a result of the bad bacteria dying off and releasing their toxins. Instead of stopping supplements altogether, Huffnagle recommends decreasing your dose and then gradually increasing it over time. “There's no evidence that you can overdo it,” he says.

Kate Hanley is a Brooklyn-based writer and the founder of www.msmindbody.com. She eats more yogurt, pickles, and kimchi since writing this article.