Tagatose

Tagatose is a naturally occurring monosaccharide found in small amounts in dairy products, particularly heated milk and some fermented dairy foods. It is isomeric with fructose — both have the same chemical formula — but tagatose has a distinctly different molecular arrangement that gives it unique metabolic properties. As a food additive it functions as a bulk sweetener with approximately 75–92% of the sweetness of sucrose, while providing considerably fewer available calories due to its limited absorption. It also contributes to Maillard browning reactions, making it useful in bakery applications.

JECFA evaluated tagatose in 2004 and classified the ADI as "not specified," based on a thorough toxicological assessment that found no grounds for a quantitative upper limit at likely dietary intake levels. Tagatose is only partially absorbed in the small intestine; the fraction that reaches the colon is fermented by gut microbiota, generating short-chain fatty acids. Clinical studies indicate it has a low glycaemic index and does not significantly raise blood glucose, which has attracted interest for use in diabetic-friendly products.

Tagatose is approved in the EU and other markets as a sweetener and bulking agent. It is tooth-friendly — oral bacteria cannot ferment it efficiently — and may support dental health as a sugar substitute. Like other poorly absorbed polyols and sugar substitutes, it can cause gastrointestinal symptoms including bloating and loose stools when consumed in excess. Its natural occurrence in dairy and its relatively clean metabolic profile position it well in the growing market for less-processed natural sweetener alternatives. Consumers managing blood sugar should note that while tagatose has low glycaemic impact, total carbohydrate content still matters in a balanced diet.