Lactose is a sugar found in milk that consists of two sugar subunits linked together. Lactase is a digestive enzyme that is responsible for cleaving the bond between the simple sugar subunits. This allows the sugar to then be absorbed through the gastrointestinal (GI) tract. As infants, the gene expressing lactase is turned on in many of our intestinal lining cells to allow us to digest our mother's milk.

As you grow and stop breastfeeding, these genes often get turned off. In some people, the enzyme is no longer produced at all. It is estimated that 75% of the world's population is deficient in lactase. Without sufficient amounts of this enzyme in the intestine, people are unable to properly digest dairy products. This results in a condition known as lactose intolerance.

Understanding Lactose Intolerance

This condition results in a set of uncomfortable digestive symptoms whenever dairy is consumed. It is hallmarked by the inability to properly digest the lactose in dairy products due to a deficiency of the enzyme lactase. Your body can only absorb single sugar units through your digestive tract lining. Since lactose is a disaccharide, meaning it is made up of two linked sugars, it cannot be absorbed without first being cleaved into subunits by lactase. As such, when a lactose intolerant individual consumes lactose, it passes along the GI tract where it has one of two effects. 

First, some lactose is digested by certain bacteria in your gut that use chemical reactions to break down the sugar, which unfortunately also results in the production of gas. While bacteria digest some lactose, the rest will continue travelling through the GI tract unable to be absorbed. While passing, it irritates the lining and draws water from the body tissues, causing cramping and loose stools. 

Because of these two effects combined, people with lactose intolerance can have nausea, gas, cramping, and diarrhea when they ingest dairy products. Supplementation with a lactase enzyme before eating dairy generally eliminates these symptoms. A simple glucose hydrogen breath test can be used to check for lactose intolerance with your healthcare practitioner.

Uncovering Dairy Sensitivities

Some people have problems digesting milk, even when sufficient lactase is present. These people will not benefit from lactase supplementation, and will only stop having digestive symptoms when dairy is removed from their diet entirely. This condition is called "dairy sensitivity" and represents a food intolerance. Although the symptoms may be similar, dairy sensitivity involves an immune reaction to the proteins in milk products, instead of the sugar. Dairy must be removed from the diet of these people to prevent systemic inflammation and the development of chronic disease.

Key Dairy Alternatives

Dairy does not just include cow's milk. Goats and other animal milk still contain high levels of lactose. For those unable to eat animal dairy, there are several dairy alternatives available on the market. Milk alternatives are soy milk, oat milk, coconut milk, and nut milk (such as almond milk), amongst others. Cheese, yogurt, and ice cream alternatives are also easily available in most supermarkets. Lactose-intolerant individuals can also purchase animal milk pre-treated with a lactase enzyme as an alternative.

The Probiotic and Lactose Connection

Some probiotic strains can help with lactose digestion in people with lowered levels of the lactase enzyme. Species that have been studied for the benefit are some Lactobacilli (L. acidophilus, L. bulgaricus, and reuteri), although generally mixed-strain probiotic formulations provide the most benefit to digestion. In general, supplementation of probiotics helps to weed out gas-producing bacteria in the intestines but is not as successful as lactase supplementation for lactose intolerance.

Tips For Taking Lactase Enzyme Supplements

Lactase supplements come in liquids, pills or capsules that are swallowed before ingesting a meal containing lactose. The typical dose of lactase is 6000-9000 FCCLU tablets, although the dose can vary widely depending on your size and your lactase production levels as well as the amount of lactose ingested.

Final Thoughts & Considerations On Lactase Enzyme Supplements

Showing an amount of enzyme by weight is not pertinent information on a supplement label as it is the enzyme's activity that is important and independent of weight. Supplements may show FCCLU (food chemical codex lactose units), LacU/LU (lactase units), on the label.