Probiotics Primer

What they are
Naturally occurring microorganisms that can be good for your health. They're added to foods, especially yogurt.

What studies show
Certain probiotics can help you fight colds, diarrhea, and more. But those aren't always the ones in your food.

Source: Mary Ellen Sanders, Ph.D., who studies probiotic microbiology and consults in the industry

Step 1: Know names
See the three circles on the right? They show the three elements of a probiotic's name. The trouble is, most companies list only the genus and species of a strain. That's like a restaurant serving "fish" without identifying what kind it is. Not having enough information makes determining any health benefits a difficult task.

Your move: Choose products that include the full names of their probiotics. Chances are, more research is available about the benefits, which is why the food company chose to spotlight the strains it included.

Here's Lactobacillus rhamnosus HN001—the full name of a probiotic in Stonyfield Farm yogurt—dissected.
Genus: Lactobacillus
Strain: HN001
Species: Rhamnosus

Step 2: Ignore the usual suspects
Take these, for example...

L. Bulgaricus, S. Thermophilus
Help turn milk into yogurt

Your move: Don't be impressed by foods that list only L. bulgaricus and S. thermophilus. These organisms do help you digest lactose, but they mostly just help create yogurt. To be labeled a probiotic, an organism has to have a health benefit. L. acidophilus is also common. Some companies use studied strains of it as probiotics, but others use it only for flavor.

Step 3: Vet research
Bifidobacterium lactis DN-173 010 is found only in Dannon Activia—because Dannon developed it, studied it, and patented it. (Dannon claims this strain helps regulate your digestive system.) This is common: Many strains are studied primarily by the companies that developed them. Then the companies promote the benefits.

Your move: Watch for definite claims, like "clinically proven" or "scientifically proven"—Dannon had to scrap both of these claims in a 2010 settlement and replace them with less-certain phrases, such as "clinical studies show."

Step 4: Read the label closely
Questions about probiotics shouldn't stop you from eating yogurt, a good source of protein and calcium. Hey, if the live cultures have other health benefits, that's all the better. Probiotic supplements are another story: Many may have no proven benefits. Look for products with labels that list probiotics' full names, the number of colony-forming units, and the scientifically studied benefits of each strain. Dosage and storage suggestions should also be included.