Do Lactase Enzymes Work Against Lactose Intolerance?

Lactose intolerance is a digestive condition in which the body is not able to digest lactose, a sugar composed of galactose and glucose. People with lactose intolerance cannot consume lactose-containing food such as dairy items, which makes it a bothersome condition.

lactose intoleranceImage Credit: Albina Glisic /

Bloating, diarrhea, stomach pains, vomiting, and stomach cramps are some symptoms associated with lactose intolerance. Usually, the symptoms develop in a couple of hours after ingestion; however, the onset and severity of symptoms may vary among different individuals.

As the symptoms of lactose intolerance mimic several other conditions such as irritable bowel syndrome, it is essential to consult a doctor for the correct diagnosis.

What causes lactose intolerance?

Lactose is digested into its constituents, galactose, and glucose, by the enzyme lactase. This process makes it easier for the body to absorb the sugars into the blood.

In patients with lactose intolerance, there is inadequate or impaired production of lactase; thus, lactose remains undigested in the digestive system. The fermentation of undigested lactose by gut bacteria leads to the synthesis of various gases, which leads to the characteristic symptoms of lactose intolerance.

Lactose intolerance is usually inherited and runs in families. Such cases are permanent and do not change throughout a person’s life. However, there are also temporary cases of lactose intolerance, which may develop after conditions such as an infection. The temporary form lasts only for a few weeks.

Worldwide, adult-onset lactose intolerance is common. Persons living in Africa and Asia are very unlikely to retain lactase activity as adults, whereas those living in Northern Europe are the most likely to retain lactase enzyme activity in adulthood.

How is lactose intolerance treated?

There is no treatment available to cure lactose intolerance. Restricting lactose-containing food is recommended to control the symptoms. Many lactose-free products are commercially available such as lactose-free milk, lactose-free yogurts, and potato milks.

Due to the lack of intake of dairy products, calcium and vitamin D supplements are prescribed to lactose-intolerant individuals to ensure that the body gets the required quantities of these essential components. Some non-dairy milk alternatives are fortified with calcium and vitamin D as well.

Lactase Enzymes for lactose intolerance

In some cases, doctors may advise exogenous oral lactase enzymes for lactose intolerance. Lactase enzymes are synthesized from fungi or yeasts and are available in the form of gels, liquids, capsules, or tablets.

The standard dose of lactase enzyme is 6,000 to 9,000 international units (IU) to be taken immediately before a dairy-containing meal. It is always advised to start at a low dose and increase the dose incrementally.

Safety aspects of Lactase enzyme supplements

Lactase enzyme supplements are safe to use and well-tolerated with no known adverse effects. However, caution should be exercised in certain individuals, such as diabetics. As lactase is digested into simple sugars, it is important to check the blood sugar levels in diabetes patients after taking lactase to ensure that they are not absorbing excessive amounts of the constituent sugars

In some cases, lactase enzyme can also trigger allergic reactions, such as anaphylaxis. Anaphylaxis, if untreated, may lead to serious consequences such as shock, coma, and in extreme cases, death.

Due to a lack of safety information, lactase supplements are not recommended for pregnant or breastfeeding women.

How effective are lactase enzymes in lactose intolerance?

Even though there are many benefits of lactase supplements, efficacy data related to the enzyme is sparse.

As per a randomized trial published in 2010, in the journal European Review for Medical and Pharmacological Sciences, lactase supplements strongly improve lactose breath test results and gastrointestinal symptoms in lactose-intolerant patients. The lactose breath test is a test used to measure lactose intolerance. The study, which included 60 subjects, demonstrated that lactase supplement taken 15 minutes before food normalizes lactose metabolization to levels comparable to those provided by probiotic Lactobacillus reuteri. Additionally, lactose supplements were also found to alleviate lactose intolerance symptoms, such as gas.

In contrast, a 2014 study published in the journal BioMed Research International reported variable outcomes to lactase supplementation. Of the 96 persons who took a lactose supplement, only 21.88% demonstrated complete normalization using the lactase breath test, whereas 17.71% had no response.

The conflicting results suggest that apart from lactase enzymes, other factors may also contribute to the inability to metabolize lactose, and further studies are warranted to clarify the same.


Lactose intolerance. NHS. Available at:

Szilagyi, A., & Ishayek, N. (2018). Lactose Intolerance, Dairy Avoidance, and Treatment Options. Nutrients, 10(12), 1994. doi:10.3390/nu10121994

Ojetti V, Gigante G, Gabrielli M, et al. The effect of oral supplementation with Lactobacillus reuteri or tilactase in lactose intolerant patients: randomized trial. Eur Rev Med Pharmacol Sci. 2010 Mar;14(3):163-70.

Ibba, I., Gilli, A., Boi, M. F., & Usai, P. (2014). Effects of exogenous lactase administration on hydrogen breath excretion and intestinal symptoms in patients presenting lactose malabsorption and intolerance. BioMed research international, 2014, 680196. doi:10.1155/2014/680196

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Last Updated: Nov 7, 2019


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