Lactase

Also indexed as: Milk Sugar Enzyme

Illustration

Lactase is the enzyme in the small intestine that digests lactose (the naturally occurring sugar in milk).

Where is it found?

Lactase is produced by the body. Dairy products have varying levels of lactose, which affects how much lactase is required for proper digestion. Milk, ice cream, and yogurt contain significant amounts of lactose—although for complex reasons yogurt often doesn’t trigger symptoms in lactose-intolerant people.

Lactase has been used in connection with the following conditions (refer to the individual health concern for complete information):

Science Ratings Health Concerns
3Stars

Diarrhea (for lactose-intolerant people)

Indigestion and heartburn (for lactose-intolerant people)

Irritable bowel syndrome (for lactose-intolerant people)

Lactose intolerance
3Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Who is likely to be deficient?

Only one-third of all people retain the ability to digest lactose into adulthood. Most individuals of Asian, African, and Native American descent are lactose intolerant. In addition, half of Hispanics and about 20 percent of Caucasians do not produce lactase as adults.1

How much is usually taken?

Lactose-reduced milk is available and can be used in the same quantities as regular milk. Lactase drops can be added to regular milk 24 hours before drinking to reduce lactose levels. Lactase drops, capsules, and tablets can also be taken directly, as needed, immediately before a meal that includes lactose-containing dairy products. The degree of lactose intolerance varies by individual, so a greater or lesser amount of lactase may be needed to eliminate symptoms of lactose intolerance.

Are there any side effects or interactions?

Lactase is safe and does not produce side effects.

Some, but not all, studies suggest that lactose-intolerant individuals absorb less calcium.2

At the time of writing, there were no well-known drug interactions with lactase.

References

1. Gudmand-Hoyer E. The clinical significance of disaccharide maldigestion. Am J Clin Nutr 1994;59(3):735S–41S.

2. Wheadon M, Goulding A, Barbezat GO, et al. Lactose malabsorption and calcium intake as risk factors for osteoporosis in elderly New Zealand women. NZ Med J 1991;104:417–9.