Lactase
An enzyme that breaks down milk sugar (lactose), used to make dairy products suitable for people with lactose intolerance.
What is it?
Lactase (also called beta-galactosidase) is an enzyme that cleaves lactose, the principal sugar in milk, into its two component simple sugars: glucose and galactose. It occurs naturally in the lining of the small intestine in most mammals, including humans, and is also produced commercially by fermentation using food-grade moulds and yeasts, chiefly Kluyveromyces lactis and Aspergillus oryzae. The commercial enzyme used in food production is microbial in origin.
What does it do?
When added to milk or dairy products, lactase hydrolyses lactose molecules before the food reaches the consumer. This means the lactose has already been split into glucose and galactose by the time the product is eaten, so people who produce insufficient lactase in their own gut can digest the product without symptoms. The enzyme is active at refrigeration and room temperatures and is typically added during processing; it continues working slowly in the packaged product. The resulting food tastes slightly sweeter than conventional dairy because glucose and galactose are sweeter than lactose.
Where you will see it
Lactose-free and reduced-lactose milk, yoghurt, cream, cheese, ice cream and other dairy products. It is also used in some infant formulas where lower lactose content is specified. On UK labels it will appear as 'lactase' in the ingredients list, or may be declared in the allergen information context of manufacturing processes. Some products use it as a processing aid and may not list it on the label at all if no active enzyme remains in the final product.
What the science says
Lactase in the gut: a normal human enzyme
Lactase is not a foreign chemical -- it is the same enzyme the human gut lining produces to digest milk sugar. People with lactose intolerance produce less of it than those without, leading to undigested lactose reaching the large intestine where bacteria ferment it, causing bloating and discomfort. Adding the enzyme to food ahead of consumption simply replicates digestion that would otherwise happen in the small intestine. There is no toxicological concern specific to ingested food-grade lactase.
Lactase (beta-galactosidase) is produced by enterocytes in the small intestinal brush border and is essential for lactose digestion; its decline after weaning is the biological basis of lactose intolerance, affecting an estimated 65% of adults worldwide.
Regulatory evaluation of microbial lactase as a food enzyme
Under EU and UK food enzyme regulations, food enzymes must be assessed for safety before they can be used. EFSA's Panel on Food Additives and Nutrient Sources assessed multiple lactase preparations and found no safety concern for their intended uses in dairy processing at the levels needed to achieve lactose reduction. EFSA did note that some preparations carry residual proteins from the production organism that could theoretically trigger a reaction in people with known allergies to the source organism, but this was not identified as a concern for the general population.
EFSA's enzyme evaluations of lactase preparations from Kluyveromyces lactis and Aspergillus oryzae concluded that no safety concern arises at the proposed use levels in dairy applications.
Allergen considerations
Lactase itself is not a declarable allergen under UK food law. However, microbially produced enzymes can carry trace proteins from their production organism. People with known hypersensitivity to Aspergillus moulds or Kluyveromyces yeasts could theoretically react to trace residuals in a preparation, though this is not an established consumer risk at food-processing doses. The enzyme is not derived from milk and does not itself contain lactose or dairy allergens.
Occupational sensitisation to fungal-derived food enzymes (including those from Aspergillus spp.) has been documented in bakery and food-processing workers exposed to enzyme dusts at levels far above what a consumer would encounter in food.
Where it stands with the regulators
Who should be careful
People with known hypersensitivity or allergy to Kluyveromyces yeast or Aspergillus mould species may wish to be aware that food-grade lactase is often produced using these organisms, though trace residues in finished products are typically very low. No avoidance is recommended for the general population. Look for 'lactase' in the ingredients list on lactose-free dairy products.
The honest read
Lactase is one of the most straightforward substances on any E-number list. It is the same enzyme the human body uses to digest milk sugar, produced by well-established food-grade microorganisms and used to pre-digest lactose in dairy products before they reach the shelf. EFSA and equivalent bodies have reviewed multiple commercial lactase preparations and raised no concern for consumers. The only genuine caveat -- occupational sensitisation in workers handling enzyme powders at high concentrations -- is irrelevant to eating a pot of lactose-free yoghurt. The science here is not live or contested.
Related additives
Common questions
Is E1106 banned in the UK?
No. Lactase is not banned. It is used legally in the UK in lactose-free dairy products under the food enzymes regulatory framework (assimilated EU Regulation 1332/2008). It is not listed as a food additive on the FSA approved additives list because it is categorised as a food enzyme, which is a separate regulatory category.
Why does E1106 appear on some E-number lists but not on the FSA approved additives page?
Food enzymes and food additives are regulated under different frameworks in the UK and EU. The FSA approved additives list covers substances regulated under the food additives rules; lactase is governed by the food enzymes rules instead. Some general E-number reference sites include it as E1106 for completeness, but that designation is not formally assigned under the food additives regulation.
What foods contain E1106?
Lactose-free milk, yoghurt, cream, ice cream, and other dairy products are the main sources. Some infant formulas also use it. The label will typically say 'lactase' in the ingredients, or the product will carry a 'lactose-free' claim that indicates the enzyme has been used.
Is E1106 vegan?
Food-grade lactase is almost always produced by fermenting Kluyveromyces lactis (a yeast) or Aspergillus oryzae (a mould), making it suitable for vegans and vegetarians. It is not derived from animal sources in commercial food production. However, if you follow a strict vegan diet, checking with the specific manufacturer is always the most reliable step, as production methods can vary.
Sources
- Approved additives and E numbers -- Food Standards Agency
- EU Rules on Food Enzymes -- European Commission Food Safety
- Regulation (EC) No 1332/2008 on food enzymes -- legislation.gov.uk
- Regulating Food Enzymes in the EU -- Food Safety Authority of Ireland
- NIH Genetics Home Reference -- Lactose intolerance
- Houba et al. -- Enzyme sensitisation in workers in the food industry, Occupational and Environmental Medicine
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