Probability of Being Lactose Intolerant

Lactose intolerance affects approximately 36% of Americans to some degree, though prevalence varies enormously by ethnic background. About 80-90% of African Americans, 80-100% of Native Americans, 90-100% of Asian Americans, 50-80% of Hispanic Americans, and 15-20% of Northern European Americans are lactose intolerant.

Lactose intolerance occurs when the body doesn't produce enough lactase, the enzyme needed to digest lactose (milk sugar). Primary lactose intolerance (the most common form) develops gradually as lactase production naturally decreases after weaning. Secondary lactose intolerance can result from injury to the small intestine from illness, surgery, or celiac disease.

Symptoms include bloating, diarrhea, gas, and abdominal cramps, typically occurring 30 minutes to 2 hours after consuming dairy. Most lactose-intolerant people can tolerate small amounts of dairy, especially fermented products like yogurt and aged cheeses (which have reduced lactose). Lactase enzyme supplements, lactose-free dairy products, and calcium-fortified non-dairy alternatives are widely available management options.