May 30, 2003 -- For people with lactose intolerance, a yogurt-like drink called kefir could put dairy in their diet again.
Lactose intolerance is a very common digestive problem caused by too little of an enzyme called lactase, which the body needs to digest lactose -- milk sugar. Gas, bloating, and diarrhea are the result.
The problem varies much from person to person; some people have to steer clear of all milk products, while others can indulge in small portions.
Kefir is an obscure, slightly more expensive alternative to milk, developed centuries ago and credited with various health-promoting properties, explains lead researcher Steven R. Hertzler, PhD, RD, a professor at Ohio State University in Columbus.
His study appears in the current issue of the Journal of the American Dietetic Association.
Historically, kefir has been prepared using the milk from sheep, goats, and cows, although soy milk kefirs are now commercially available, he explains.
Like yogurt, which is made from fermented milk, kefir contains lots of bacteria that aid lactose digestion. Yogurt doesn't produce symptoms of lactose intolerance because these bacteria help digest the lactose. However, kefir has a broader range of nutrients than does yogurt, he says.
Kefir is drinkable, with a rather tart taste, and a consistency somewhat thicker than milk, Hertzler explains in a news release.
In his study, Hertzler included 15 otherwise healthy men and women, all who were lactose intolerant. Each was asked to eat five separate test foods: 2% milk, plain kefir, raspberry-flavored kefir, plain yogurt, and raspberry-flavored yogurt.
They ate each food after a 12-hour fast. Eight hours later, they took hourly tests to measure breath hydrogen -- a measure of too much gas in the digestive tract. They were also asked to note any symptoms of lactose intolerance during the eight-hour period.
Good news -- participants reported few or no symptoms after eating the yogurt and kefir. Gas was the only symptom they reported. But after drinking kefir, they reported half as much gas, compared with drinking milk. They also had lower breath hydrogen levels after drinking kefir.
Kefir might be a better option than yogurt for some lactose-intolerant people, Hertzler says. Though both kefir and yogurt are good sources of calcium, potassium, and protein, kefir also contains a wider array of digestion-boosting bacteria.