Pondering on Yogurt and Health

The other day I was watching some TV with my mother when an advertisement for probiotic yogurt popped up. The ad was suggesting that this particular yogurt’s combo of probiotic bacteria would boost immune system function and help digestion and blah blah goodness. So mom asks what probiotics were, exactly, and if they are any different than the bog standard bacteria used to culture milk into yogurt. It’s good question.

The most common probiotics - which generally refers to microbes that promote health in some way or another - are species from the Lactobacillus and Bifidobacterium genera. Both of them can turn sugars in to lactic acid (ie ferment) and thereby make yogurt.

Which leaves us with two questions. 1) Do probiotics promote health? 2) Are the pricey probiotic-labeled yogurts better than your average tub?

1) Yes! Happy bacteria do seem to promote good health. The list of purported benefits is long indeed, but among the best proven is bowel problems… Take this 2005 study on preventing antibiotic-associated diarrhea in babies using two strains of bacteria often used in yogurt production: Bifidobacterium lactis and Streptococcus thermophilus.

There are a whack of other claims, but the science is still in its infancy, really. Here’s a sampling: Probiotics have show some effectiveness in combating stomach ulcers (likely by out competing off the bad H. pylori bacteria). Probiotics might help prevent allergies in kids...but a recent review from the Cochrane Database (who do very good, standardized and objective analyses) found little hard evidence of their powers.

2) For this, the answer is even more murky...for the people marketing the extra healthy yogurts would have you believe. that their special blend or unique species is the key to eternal life. While it’s true that clinical trials testing the effects of specific bacteria can only then be applied that same bacteria in the same dose, I don’t buy that their particular brand of oh-so-special bacteria is oh-so-special. The major mode of action of all these probiotics is out-competing bad bacteria, so if a species survives past the stomach and into the gut, it can probably do that. Maybe there’s some extra peppy bacteria, but I remain underwhelmed.

Let’s take my favorite brand of yogurt, Astro, as an example. Astro makes lots of different yogurts including their BioBest probiotic yogurt, BioBest Vitalite probiotic yogurt (special for digestion with prebiotics..the food that probiotics like to eat) and their normal stuff.

In the BioBest Vitalite we have “active bacterial cultures” comprising Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus acidophilus, Bifidobacterium lactis and Lactobacillus casei.
In the BioBest we have “active bacterial cultures” comprising Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus acidophilus and Lactobacillus bifidus (old name of Bifidobacterium bifidum)
In the regular stuff we have “active bacterial cultures”.

So what’s in the normal stuff? How much of the good stuff is in the probiotic-labeled stuff? My guess is that the regular stuff has the first two cultures - Streptococcus and L. bulgaricus - as they are very common yogurt bacterias. Researchers studying their survival in the human gut previously found conflicting results, but recent reports suggest that yes! they can live in the gut and yes! that makes them probiotics! Probably.

And while companies probably have lots of data saying that their blend can do this that or the other thing, until I see some controlled clinical trials showing that special health bacteria is better than the ho-hum brand of yogurt that I love (Astro Strawberries and Cream, no slimy fruit chunks and only 1% fat), I ain’t wasting my money on a marketing ploy.