A pilot study failed to show something many people believe – that drinking raw milk reduces the symptoms of lactose intolerance or malabsorption.
The condition is common worldwide, and can lead to bloating, abdominal pain and diarrhea. But the specific prevalence of lactose intolerance is not known, the researchers from Stanford University said.
Current coping strategies include not drinking milk, drinking lactose-free dairy products, taking lactase enzyme tablets and other behaviors, but none of those eliminate the symptoms, the researchers wrote.
"Recently, unpasteurized raw milk consumption has increased in popularity and emerged into a nationwide movement despite the acknowledgment of risks associated" with pathogens, the researchers wrote this week in the Annals of Family Medicine.
Late last year the American Academy of Pediatrics warned pregnant women and children not to drink raw milk and said it supports a nationwide ban on its sale because of the danger of bacterial illnesses. Still, raw milk sales are legal in many places, including California and 29 other states.
Advocates say raw milk is delicious and provides health benefits, including protection against asthma and lactose intolerance. And when the animals are raised properly and the milk is treated carefully, they say, raw milk poses little danger to human health.
But the pilot study, conducted in 2010 with 16 people who identified themselves as lactose intolerant and suffering symptoms that were moderate to severe, did not show a benefit from raw milk. The participants, recruited from around Stanford, drank raw whole milk, pasteurized whole milk, and soy milk – all vanilla flavored to prevent them from detecting which was which. They drank specified amounts over eight days and were tested at many points for lactose malabsorption.
The trial "provided no evidence that raw milk is better tolerated by adults positive for lactose malabsorption, either objectively or subjectively," the researchers wrote.
Previous studies have shown that unpasteurized yogurt can help sufferers. That could be, the researchers said, because of yogurt's greater viscosity – which means it takes longer to digest. That gives the the good bacteria in yogurt more time to act on the lactose in the small intestine, they speculated.
It's also conceivable that people need to adjust to raw milk and eight days was not enough, they said. Additional work should be done to test that idea, they wrote.