Recently, I have been seeing a lot of posts on social media about the purported benefits of raw milk. One claim was that people who drink raw (unpasteurized) milk experience no symptoms of lactose intolerance. The stated reason? That the bacteria in unpasteurized milk is somehow beneficial to those with lactose intolerance, whose guts are purportedly lacking in certain "healthy" bacteria.
This makes no sense to me. People with lactose intolerance have trouble digesting milk because the cells in their intestines produce insufficient amounts of the lactase enzyme needed to break down lactose, or milk sugar. And in fact, it is the interactions between normal intestinal bacteria and the lactose that cause many of the classic symptoms of lactose intolerance, such as gas, bloating and diarrhea.
Now, a small study from Stanford University further undermines the claim that bacteria in unpasteurized milk can help those with lactose intolerance. The researchers recruited 16 lactose-intolerant people and randomly assigned them to consume one of three types of milk over eight days: raw, pasteurized or soy. The study subjects followed this with a week of drinking no milk and then repeated the process with the other two types of milk. Throughout the study, the participants underwent hydrogen breath tests (which can pinpoint certain chemical reactions that are signs of lactose intolerance) and recorded their symptoms. At the end, the investigators found no significant difference between those who drank the raw milk and those who drank the pasteurized milk.
I wouldn't mind seeing some bigger studies on the effects of unpasteurized milk on those with lactose intolerance. But I wouldn’t bet my money on raw milk, and given the high risk for foodborne illness—untreated milk can contain harmful germs—I don’t think I will be drinking it anytime soon.