In my experimentation with homemade yogurt (which is going really well, actually) I have been investigating the idea of cultures.  Yogurt, as we all know, is milk which has been partially digested by a collection of bacteria.  Gross, I know, but that's how the world works.  

We know that having bacteria digest your milk can make it easier to digest.  And tastier, and a much better base for smoothies.  We also know that these same bacteria are found naturally in your digestive system.  If you kill them off with a course of antibiotics, it can be very helpful to eat some yogurt in order to replenish their numbers.

Beyond that are what I would call "off-label uses."  Some of these uses are more reliable than others.  For example, countless women swear that plain yogurt can cure a yeast infection.  (Although in order to work, it must be applied topically, if you follow me.)  The acidity of the yogurt alone is probably responsible for most of this effect, since yeast infections are frequently caused or exacerbated by a disruption of the natural pH levels.

Another "off-label use" is the collection of vague claims put forth by Dannon with regards to its Activia yogurt.  You can tell how vague these claims are, because no one is really sure whether Activia is meant to cure diarrhea or constipation.  

Yogurt is frequently recommended for people with diarrhea, but Activia is pitched as a weight loss tool in other countries (the faster food moves through your system, the less of it gets absorbed and converted to fat).  Jamie Lee Curtis is no help here, extolling as she does the claims of "regularity."

Further complicating these claims is the wee little matter of the fact that probiotics (the collective term for all of these helpful bacteria) have never been clinically proven to do anything other than turn milk into yogurt.  Probiotics are the marketing darling of the day, but their usefulness is entirely unproven.

The very word "probiotics" is phenomenally vague.  It refers in general to organisms which are helpful to their hosts - the opposite of parasites, in other words.  A whole whack of organisms can fall into the category of probiotics, from the Lactobacillus found in yogurt to the yeast used to make bread.

Dannon's advertising has to rely on vague terms like "discomfort" and "irregularity," because these are not claims which are regulated by the FDA.  Dannon has gotten in trouble in the past with making overblown health claims for its yogurt.  It was the subject of a class action lawsuit in California regarding DanActive's claims of boosting immunity and fighting colds.  

If Dannon says anything more specific than "difficulty," the FDA will step in and require it to produce scientific proof to back up its claims.  The FDA requires that any product which claims to treat a medical condition has to show proof.  But as long as Dannon keeps it vague, they can claim their yogurt is good for just about anything.

In truth, the only thing we know about yogurt for sure is that it is tasty.  Beyond that, it's just speculation.

Creative Commons-licensed image courtesy of Flickr user neon.mamacita