The yogurts used in Bolling’s study contained the bacteria strains Streptococcus thermophilus, Lactobacillus bulgaricus, and Lactobacillus acidophilus. The lactose-intolerant or otherwise yogurt-averse could simply take those as probiotic pills, but Bolling says it could be that there’s something about the dairy itself that could be beneficial, above and beyond the benefit of the active cultures. A review paper found that dairy products themselves could be anti-inflammatory—in subjects who weren’t allergic to cow milk, of course.
The calcium might help you absorb less fat, Childs says. Because yogurt is protein-rich, it makes you feel more full. And if you’re trying to eat two yogurts a day, like the women in the study did, you might wind up eating fewer unhealthy snacks. You probably wouldn’t do that if you were just taking probiotic pills.
There are still reasons why all the excitement about yogurt could, uh, curdle. (Sorry.) Childs told me it’s not really clear how often people have to eat yogurt or probiotics to see benefits from them. “It seems likely that you have to eat it consistently,” she said. “The food industry would be very happy to have us eat it every day.”
And lo, Bolling’s study was funded by the National Dairy Council, a non-profit that’s supported by the U.S. Department of Agriculture.
Bolling defended the funding stream, saying, “Whether or not we had the study funded through NIH, or Dairy Council, or USDA, or some other funding agency, we’d come to the same conclusions.”
Also, because they were eating so much yogurt and pudding, the obese women gained about a kilogram of weight during the nine-week study.
“The [health] benefits may not be apparent in women who are not obese,” said James Versalovic, a professor of immunology at the Baylor College of Medicine in Texas. “The results were mixed and not uniformly positive, and the elevated sugar content in yogurt may have clouded possible benefits.” Plus, he added, if the “eating challenge” the women were given had been a healthier meal, instead of the sausage sandwiches, they might not have seen as significant of an anti-inflammatory benefit from the yogurt.
So, maybe, if you have an otherwise healthy diet, yogurt and its healthy microbes could nudge you toward even better health by reducing inflammation. But Versalovic says that by itself, it’s probably not enough to prevent inflammation-related diseases.
Childs agreed, saying, “we’re not quite there yet with the research” to show that yogurt can prevent things like asthma and arthritis. But there’s little risk attached to eating yogurt anyway.
And so we come to the most common reasons why certain foods are deemed “healthy”: It looks like they might benefit us, they don’t appear to cause harm, and they’re rather tasty, so why the heck not. In the messy world of nutrition research, that’s sometimes as close as we can get. When you add marketers to the mix, a health craze is born.
Objectively, I know it’s still premature to rely on yogurt to treat anything in particular. But when I was working on this piece, I nevertheless couldn’t resist emailing my mom, who suffers from painful arthritis, “Have you considered eating a yogurt every day?”
I figure it can’t hurt.