Tagatose
A naturally-occurring rare sugar used as a low-calorie sweetener, with about 38% of the sweetness of sugar and minimal impact on blood glucose.
What is it?
D-tagatose is a monosaccharide (simple sugar) that occurs naturally in tiny amounts in some dairy products and fruits. Commercially it is produced by enzymatic or chemical conversion of galactose or fructose. It looks and tastes similar to table sugar but is only partially absorbed in the small intestine, so it delivers fewer calories (around 1.5 kcal/g) and causes a much smaller rise in blood glucose than sucrose.
What does it do?
Tagatose provides sweetness with a flavour profile very close to sucrose. Because most of it is not absorbed in the small intestine, it passes to the large intestine where gut bacteria ferment it. This fermentation has prebiotic effects, selectively feeding beneficial bacteria such as Bifidobacteria and Lactobacilli. The low glycaemic impact makes it of interest to formulators targeting reduced-sugar or diabetic-friendly products. It also resists caramelisation differently from sucrose, which affects baking applications.
Where you will see it
Used in reduced-calorie soft drinks, protein shakes, meal-replacement drinks, sugar-free confectionery, chewing gum, breakfast cereals, flavoured yogurts, and some baked goods marketed as low-sugar. On a UK label it appears as 'tagatose' or 'D-tagatose' in the ingredients list. Products with more than 15g per serving or beverages with more than 1% tagatose must carry the warning: 'excessive consumption may produce laxative effects'.
What the science says
Glycaemic response
Several controlled studies have found that tagatose raises blood glucose and insulin levels far less than an equivalent amount of sucrose. EFSA reviewed the evidence and found that consuming at least 7.5g per meal is sufficient to produce a meaningful reduction in the post-meal blood glucose rise. This effect is attributed to its incomplete absorption in the small intestine rather than any active mechanism.
At doses of 7.5g per meal or above, tagatose produces a measurable reduction in post-prandial blood glucose compared with sucrose.
A clinical study in subjects with type 2 diabetes found that tagatose supplementation improved glycaemic control markers including HbA1c over a 3-month period.
Gastrointestinal effects
Because tagatose is only partially absorbed in the small intestine, the remainder reaches the colon and is fermented by gut bacteria. At lower intakes this is the source of its prebiotic effect. At higher intakes, the osmotic load from unabsorbed sugar can produce bloating, wind, and loose stools. UK and EU rules require a laxative warning on products providing more than 15g per serving.
Intakes above approximately 30g in one sitting are associated with osmotic gastrointestinal effects including flatulence, bloating, and loose stools.
Tagatose selectively increases populations of Bifidobacteria and Lactobacilli in the colon, consistent with a prebiotic mechanism.
Dental health
Tagatose is non-cariogenic: unlike sucrose, it is not fermented by Streptococcus mutans in dental plaque to produce the acids that erode tooth enamel. EFSA accepted a health claim linking sugar replacers including tagatose to maintenance of tooth mineralisation.
EFSA confirmed that tagatose, as a sugar replacer, supports maintenance of tooth mineralisation by decreasing tooth demineralisation.
Novel food status and long-term data
Tagatose has not accumulated the decades of widespread human consumption that conventional sugars have. It is classified as a novel food in both the UK and EU, which means its ongoing use is subject to a regulatory authorisation rather than treated as automatically equivalent to traditional food ingredients. JECFA removed a formal acceptable daily intake limit after reviewing available data and concluding a numerical cap was not needed, but this reflects the evidence available at the time rather than a definitive long-term safety characterisation.
JECFA removed the numerical acceptable daily intake for tagatose, noting that the available data did not support setting a specific limit.
Where it stands with the regulators
Who should be careful
People sensitive to high-fibre or poorly-absorbed carbohydrates may experience bloating or loose stools if they consume multiple servings in one day. Anyone managing fructose malabsorption or irritable bowel syndrome should be cautious with products containing tagatose. Look for 'tagatose' or 'D-tagatose' in the ingredients list, and note the mandatory laxative warning on products providing over 15g per serving.
The honest read
Tagatose is a rare sugar that behaves quite differently from ordinary table sugar in the body. The science on its glycaemic and dental benefits is reasonably well established and has been accepted by EFSA. The main practical issue is the gastrointestinal discomfort that can arise at higher doses, which is why a mandatory warning label is required. Long-term evidence from large human populations is limited compared with traditional sugars, which is part of why it retains novel food status rather than being treated as a conventional ingredient. Current evidence does not point to any toxicological concern, but the evidence base is less deep than for sugars used for centuries.
Related additives
Common questions
Is E963 banned in the UK?
No. D-tagatose is authorised for use in the UK as a novel food under assimilated EU Regulation 2017/2470. Its authorisation was most recently updated by the UK FSA in February 2025. It is not, however, listed as a standard food additive in the main food additives permitted list.
Can tagatose cause digestive problems?
Yes, at higher intakes. Because most tagatose is not absorbed in the small intestine, it reaches the colon and is fermented by gut bacteria. This can cause bloating, wind, and loose stools, particularly at intakes above 30g in one sitting. UK law requires products to carry a laxative-effects warning if a single serving provides more than 15g of tagatose, or if a beverage contains more than 1% tagatose.
What foods contain E963?
Tagatose appears in reduced-calorie soft drinks, protein shakes, meal-replacement products, sugar-free confectionery, chewing gum, flavoured yogurts, and low-sugar baked goods. Check the ingredients list for 'tagatose' or 'D-tagatose'.
Is E963 vegan?
D-tagatose itself is vegan. It is produced commercially from galactose (typically derived from lactose in dairy by-products) or from fructose via epimerisation, or more recently from maltodextrin. The final purified tagatose contains no animal-derived material. However, some products containing tagatose may also contain dairy or other animal ingredients, so check the full ingredient list.
Sources
- FSA Assessment of Novel Food D-tagatose for Change to Conditions of Use (RP1652)
- JECFA Monograph: D-Tagatose (Food Additives Series 48)
- EFSA NDA Panel opinion on sugar replacers: glycaemic response and dental health claims
- Safety and Efficacy of D-Tagatose in Glycemic Control in Subjects with Type 2 Diabetes (PMC4820068)
- UK FSA Approved Additives and E Numbers
- Global Prebiotic Association: Tagatose Prebiotic Spotlight
- GB Novel Foods Register: D-Tagatose (novel-40) - Authorised Regulated Food and Feed Products for Great Britain
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