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According to a new pilot study, people who are lactose intolerant might not be able to digest raw milk any better than pasteurized milk. The study, conducted by researchers from the Stanford University School of Medicine, dispelled claims that raw, unpasteurized milk could be an option for people intolerant to lactose, which is a kind of sugar that is found in milk and other diary foods.

"It's not that there was a trend toward a benefit from raw milk and our study wasn't big enough to capture it; it's that there was no hint of any benefit," said nutrition expert Christopher Gardner, PhD, professor of medicine at the Stanford Prevention Research Center and senior author of the study.

For this study, the researchers recruited 16 volunteers who were tested for their lactose-intolerant status. Each participant drank three types of milk throughout the study, which were pasteurized milk, raw milk and soy milk. Since soy milk contains no lactose, it acted as the control. The three milk options had sugar-free vanilla syrup added so that the participants would not be able to differentiate which milk they were drinking. Each participant was randomly assigned different orders of drinking the milk.

The study was designed so that everyone started off with one type of milk for eight days. The amount of milk they drank increased from four ounces to 24 ounces throughout the days. They then had a one-week clearing out period before they started drinking the second type of milk at the same quantities for the same period of time. This process was repeated for the last sample of milk.

The volunteers were asked to keep a log of four specific symptoms, which were gas, diarrhea, audible bowel sounds and abdominal cramping. The symptoms were ranked from 0 to 10, with 10 being severe. The participants had the option to drink less of the milk sample if they experienced severe symptoms. The researchers tested all of the subjects' hydrogen levels using breath tests during day one and day eight for each milk sample.

The researchers discovered no significant differences in drinking pasteurized milk and unpasteurized milk for the lactose-intolerant participants. The researchers found that participants reported feeling the most severe symptoms during day seven for both milk products. Gardner concluded that the recent claims made by some raw-milk providers that raw-milk is better for lactose intolerant people because it contains "good" bacteria are false.

"When I heard that claim it didn't make sense to me because, regardless of the bacteria, raw milk and pasteurized milk have the same amount of lactose in them," Gardner said. "But I liked the idea of taking this on since it seemed like a relatively straightforward and answerable question because the symptoms of lactose-intolerance are immediate. If drinking milk makes you uncomfortable, you will know within two hours. You either have cramps and diarrhea or you don't."

The study was published in the Annals of Family Medicine.