Lactase

What it is

Lactase (beta-D-galactosidase) is a key brush-border hydrolase enzyme responsible for splitting the dietary disaccharide lactose into its absorbable monosaccharide constituents, glucose and galactose. In commercial nutritional supplements, lactase is produced through controlled fungal fermentation of Aspergillus oryzae or Kluyveromyces lactis. Supplemental lactase remains enzymatic and active in gastric fluid, hydrolyzing ingested lactose in the stomach and upper duodenum before it reaches the colon.

Also known as: Beta-Galactosidase

What it does

• Splits dietary lactose into simple, easily absorbable sugars (glucose and galactose).
• Prevents lactose-induced gas, abdominal cramping, bloating, and osmotic diarrhea.
• Improves digestive tolerance of dairy foods, milk powders, and whey protein supplements.

Amplified by probiotics

Lactase and live probiotics exhibit powerful dual synergy in managing lactose malabsorption. Supplemental fungal lactase rapidly hydrolyzes dietary lactose in the upper gastrointestinal tract. Meanwhile, microencapsulated probiotic strains—such as Lactobacillus acidophilus, Lactobacillus bulgaricus, and Streptococcus thermophilus—express endogenous beta-galactosidase within their bacterial cell walls. Upon reaching the lower intestine, these probiotics continue breaking down residual lactose through internal enzymatic activity. Furthermore, lactic acid produced by probiotics creates a mildly acidic luminal pH that stabilizes digestive enzymes and reinforces tight junction integrity, mitigating osmotic fluid shifts and abdominal distress.

Typical dose

2,500–10,000 ALU/day

The evidence

Extensive clinical trials prove that oral lactase supplementation significantly mitigates hydrogen breath levels and gastrointestinal symptoms in lactose-intolerant individuals. Both EFSA and NIH recognize lactase as an established, effective intervention for lactose maldigestion (Deng et al. 2015, Nutrients; EFSA Panel 2009, EFSA Journal).

1. Deng Y, et al. Lactose intolerance in adults: biological mechanism and dietary management. Nutrients. 2015;7(9):8020-8035. PubMed ↗
2. EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on the substantiation of health claims related to lactase enzyme. EFSA J. 2009;7(9):1236. PubMed ↗

Safety & who should check first

Exceedingly safe with no upper intake limit established; works locally inside the digestive lumen. Safe during pregnancy and breastfeeding; zero systemic side effects reported.