Anyone who has ever had a yeast infection knows that they are horrible things, so you can imagine how dismayed I was to learn my then-infant son had developed one on his otherwise sweet little bottom.

My pediatrician prescribed a special cream and some good advice—knowing that I breastfed my son, he recommended that I take a probiotic to help clear things up.

I’ve long sung the praises of taking probiotic supplements in either pill form or yogurt (or for me, soy yogurt). With no shame at all, I will tell you that I come from stock who are not unfamiliar with the annoyances of yeast infections, and we’ve got the battle down to a science.

Now, a recent study published in the Journal of Pediatrics shows that formula-fed babies have greater gut function when the probiotic organism Lactobacillus reuteri is added to their diet.

The study focused on feeding intolerance, bowel habits, and gastrointestinal movement patterns in pre-term newborns. The formula-fed babies who were given probiotics for 30 days had significantly less spit-ups and average daily crying time, but significantly more number of stools than those who didn’t get the probiotic.

This is good to know, because poor digestion is often associated with formula-fed babies.

What are probiotics? You might have heard these microorganisms called “good” or “healthy bacteria.” They maintain the natural balance of your digestive tract. Research shows that L. reuteri in particular has been shown to decrease the duration of rotavirus-related diarrhea, inhibit the growth of E. coli in the gastrointestinal tract, and reduce infant colic.

Food sources of probiotics include yogurt, buttermilk, kefir, tempeh, miso, kim chi, sauerkraut and other fermented foods, according to the University of Michigan Comprehensive Cancer Center.

The Center also notes that in order for probiotics to flourish, you should eat lots of prebiotics. These are the foods that contain nutrients that nourish the probiotics. According to the center, prebiotic foods include flax, barley and other whole grains; onions; greens (especially dandelion greens—not a usual menu item—but also spinach, collard greens, chard, kale and mustard greens); berries, bananas and other fruit; and legumes, including lentils, kidney beans, chickpeas, navy beans, white beans, and black beans.

Of course, you might not be loading your sixth-month-old’s plate down with black beans and collard greens. Luckily, yogurt is an appropriate first food for six-month-olds, and it’s full of those helpful probiotics.

If your child is under the age of two, buy whole-milk or full-fat yogurt; older children can have reduced-fat yogurt. No matter the age of your child, only buy yogurt that has two main ingredients: milk and live cultures. Ditch the ones with fillers and additives (like starches, fructose syrup and gelatin), or filled with sugar. And you don’t want yogurt that’s been “heat treated after culturing”—that kills most of the health benefits.

Instead of buying “fruit-on-the-bottom” yogurt, just buy a big container of plain-Jane yogurt and blend it with some fruit yourself. You’ll save money and end up with a healthier treat, too.

Soy yogurts do contain probiotics grown in a vegetable medium, but check the label: not all brands contain L. reuteri.

If your family has a history of dairy allergies, don’t forget to discuss giving your child yogurt with his or her doctor.