The benefits of probiotics -- the "good bacteria" that populate your gut -- are legion, and many nutritionists consider probiotics to be one of the most important supplements you can take. They help support digestion and assimilation of nutrients. And emerging evidence strongly supports the idea that probiotics are important for a healthy immune system.

But cutting belly fat?

Yup. Researchers from Finland enrolled more than 250 pregnant women in a study on pregnancy weight gain. During their first trimester, they were divided into three groups. Two groups received standard, prudent dietary advice in line with current recommendations about weight gain during pregnancy. They were also provided with lots of foods that contained monounsaturated and polyunsaturated fats, plus fiber-enriched cereals and the like. But one of these groups was given capsules of lactobacillus and bifidobacterium, commonly used families of probiotics. The third group was the control group -- the women in this group received no counseling and were given dummy capsules.

Each woman was weighed at the beginning of the study and then again 12 months after giving birth, at which time the researchers also measured their waist size and skin thickness.

The women who took the probiotic supplement did the best. Central obesity -- defined as a BMI of 30 or greater and a waist size of over 31.5 inches -- was found in 40 to 43 percent of the women in the two groups that did not take the probiotics. But only 25 percent of the women in the group that took probiotics met the standard for central obesity. Their average body fat was also a bit lower than either of the other two groups. The difference wasn't enormous, but it was significant.

"If I could only get people to take one supplement a day, it would be a probiotic," says my nutritionist friend Allison Tannis author of "Probiotic Rescue: How You can use Probiotics to Fight Cholesterol, Cancer, Superbugs, Digestive Complaints and More." "The benefits of probiotics are so far reaching it's mind boggling."