For lactose intolerant adults, drinking a fermented milk called kefir either eliminated or drastically reduced symptoms related to lactose intolerance. Researchers think that microbes in this ancient fermented milk product possess the enzyme that is necessary to digest lactose.

“Many health claims exist for kefir, including the enhancement of the immune system and improved digestive health, particularly with regard to lactose digestion,” said Steven Hertzler, an assistant professor of medical dietetics at Ohio State University. “We wanted to find out if kefir would improve lactose digestion. The research showed that it did.”

The researchers asked 15 adults to consume five separate test foods: 2% milk; plain kefir; raspberry-flavoured kefir; plain yogurt; and raspberry-flavoured yogurt. Each food was eaten after a 12-hour fast and followed up by a series of breath hydrogen tests every hour for eight hours. Participants were asked to record any symptoms of lactose intolerance for eight hours after eating each food. Participants reported having little or no symptoms associated with lactose intolerance after eating both types of yogurt and kefir. Flatulence was the most-reported symptom. Drinking kefir reduced flatulence frequency by more than half, compared to milk.

“Both kefir and yogurt improve lactose digestion simply because some of the bacterial cells give up their lives in the intestinal tract, release their enzymes and digest the lactose,” Hertzler said. “It’s a one-shot deal. However, kefir has additional microorganisms that may be able to colonize the intestines and benefit health further by protecting the intestine against disease-causing bacteria.”

Ohio State University, May 31, 2003