Lactase is a digestive enzyme naturally produced in the small intestine that breaks down lactose, the sugar found in milk and dairy products, into absorbable sugars like glucose and galactose. Individuals with reduced lactase production experience uncomfortable digestive symptoms like bloating, gas, and diarrhea—a condition known as lactose intolerance. Supplemental lactase, available over the counter, provides the necessary enzyme externally, allowing the body to digest the lactose in a meal. This external enzyme is designed to work within the digestive tract to prevent undigested lactose from reaching the colon, where it would otherwise be fermented by bacteria.
Duration of Lactase Activity After Consumption
The active period for most orally ingested lactase supplements is short, typically lasting between 30 and 60 minutes once the enzyme begins working. This temporary nature is due to the harsh, highly acidic conditions of the stomach. Since lactase is a protein, the low pH environment rapidly degrades and denatures the enzyme, effectively shutting down its ability to break down lactose.
For the supplement to be effective, it must be present and active while the lactose-containing food passes through the upper digestive system. This window is generally sufficient for the initial digestion of a single meal or snack. If a person continues to eat dairy products for a longer period, such as during a multi-course meal, the initial dose of the enzyme will likely be deactivated before the entire meal is consumed. Manufacturers often advise taking an additional dose if consuming dairy continues beyond the first hour.
Some specialized formulations, such as those that are enteric-coated or contain neutral lactase, are designed to bypass the stomach’s acidic environment. These products may persist longer, sometimes remaining active for up to four hours as they slowly release the enzyme in the more neutral pH of the small intestine. However, the majority of standard, fast-acting tablets and chewables rely on working quickly before the stomach acid renders them inert. Once the enzyme has completed its job of breaking down the lactose, or once it is deactivated, it is simply passed through the digestive system and excreted.
Factors Affecting Lactase Supplement Efficacy
The effectiveness of a lactase supplement is influenced by several variables. One significant factor is the potency, measured in Food Chemical Codex (FCC) lactase units. A higher unit count, such as 9,000 FCC units, contains more active enzyme, which is generally necessary to break down a larger amount of lactose or to compensate for a severe deficiency.
The amount of lactose consumed in the meal is a directly related factor, as a small serving of dairy requires less enzyme than a large one. The dosage must be carefully matched to the lactose load, and users often need to experiment to find the precise strength that works for their specific dietary choices. The form of the supplement also plays a role, as chewable tablets and liquid drops often begin to mix with food and work faster than capsules, which need a few minutes for the outer shell to dissolve.
The most important factor in maximizing efficacy is the timing of consumption relative to the meal. The enzyme must be introduced to the digestive tract simultaneously with the lactose, meaning the supplement should be taken immediately before or with the first bite or sip of the dairy item. If taken too early, the enzyme may be degraded by stomach acid before the lactose arrives. If taken too late, the lactose may have already begun to move out of the upper small intestine undigested. Immediate co-ingestion with food is necessary because the low pH of the stomach is the primary threat to the enzyme’s function.
Shelf Life and Storage of Lactase Supplements
The longevity of a lactase supplement before consumption is governed by its shelf life and storage conditions. Commercial lactase products are typically stable for a period indicated by an expiration date, which often ranges from one to two years from manufacture. This date marks the point at which the product is no longer guaranteed to contain the full, stated enzyme potency.
As a biological catalyst, the lactase enzyme is highly susceptible to degradation from environmental factors. The primary threats to stability are high heat, moisture, and direct light. Storing the supplements in a cool, dry place, generally below 25 degrees Celsius (77 degrees Fahrenheit), is necessary to prevent the enzyme from denaturing.
Exposure to temperatures exceeding 30 degrees Celsius, such as leaving the bottle in a hot car or near a heat source, can significantly reduce the enzyme’s activity and shorten its effective shelf life prematurely. Conversely, freezing the tablets can also destroy the delicate enzyme structure. Improper storage conditions will cause the product to lose potency well before the printed expiration date, meaning a user may take the correct dose but still experience symptoms because the enzyme count is lower than expected.