Moises Velasquez-Manoff, writing for the New York Times:
Which brings us to farm milk. In Europe, the consumption of unpasteurized milk has repeatedly correlated with protection against allergic disease. In America, 80 percent of the Amish studied by Dr. Holbreich consume raw milk. In a study published earlier this year, Dr. Schaub’s group showed that European children who consumed farm milk had more of those regulatory T-cells, irrespective of whether they lived on farms. The higher the quantity of those cells, the less likely these children were to be given diagnoses of asthma. Here, finally, is something concrete to take off the farm.
None of these scientists recommend that people consume raw milk; it can carry deadly pathogens. Rather, they hope to identify what’s protective in the milk and either extract it or preserve the ingredients during processing. Microbes may not be the key ingredient in this case. Instead, farm milk may act as a prebiotic — selectively feeding good microbes within. Another possibility is that as with human breast milk, antibodies and immune-signaling proteins in cow’s milk influence the human immune system, steering it toward tolerance.
Stories like these remind me of how clueless we still are about immunology.