Lactase (Beta-Galactosidase)

EnzymecarbohydraseModerate dose evidence

Also known as: beta-galactosidase, acid lactase, Aspergillus oryzae lactase, Lactaid enzyme, tilactase

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Lactase splits milk sugar (lactose) into glucose and galactose. People who produce little intestinal lactase experience gas, bloating, and loose stools after dairy, and oral lactase from Aspergillus oryzae taken with the meal supplies the missing activity. A placebo-controlled crossover study in lactose-intolerant adults measured symptoms and breath hydrogen after a lactose load with and without lactase. It is sold as a stand-alone chewable or capsule and included in digestive enzyme blends. Products are labeled by activity in ALU (acid lactase units) because milligrams say nothing about potency.

Research summary

Hydrolyzes lactose into glucose and galactose in the stomach and upper small intestine; studied for reductions in breath hydrogen and symptom scores after lactose intake.

Dosage

Daily amounts, of compound.

Lowest studiedTypical rangeHighest studiedUpper limit

Dose by activity: roughly 3,000–9,000 ALU taken at the start of a dairy-containing meal, with the higher end for larger lactose loads. Milligram doses are intentionally left null because raw-material potency (ALU per gram) varies several-fold between suppliers; compute mg from the supplier's ALU/g once known. Effects are per meal, not cumulative.

Standardization: Activity-standardized: 3,000–9,000 ALU per serving (ALU = acid lactase units, FCC); supplier states ALU per gram

Source material: Aspergillus oryzae fermentation

As supplied: Manufacturers quote activity (ALU per gram), not mass; mg per serving must be derived from the supplier's potency.

Format suitability

  • Capsule
  • Powder
  • Tablet
  • Softgel
  • Gummy
  • Liquid

Heat- and moisture-sensitive; capsule, dry powder, or low-heat chewable tablet. Chewables are common because the enzyme is taken with the first bite of food.

Formulation notes

Activity declines with heat and humidity; store dry. Some lactase preparations are produced on dairy-free media, but confirm allergen status for dairy-free labeling.

Sources

  1. Effect of lactase on symptoms and hydrogen breath levels in lactose intolerance: A crossover placebo-controlled study. (Baijal 2021)PubMed
  2. Food Chemicals Codex (USP) — enzyme activity unit definitionsReference
  3. NIH Dietary Supplement Label Database — lactase productsNIH DSLD

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