GLOSSARY

Disaccharide contains two monosaccharide units joined by a glycosidic bond. Units and linkage matter: lactose, sucrose and maltose are all disaccharides without being the same molecule or food source.

A common classification distinguishes one-unit monosaccharides, two-unit disaccharides, short-chain oligosaccharides and longer polysaccharides. The FAO framework generally places oligosaccharides at 3–9 units and polysaccharides at 10 or more. Some sources use different boundaries, so the convention being applied should be stated rather than assumed universal.

Normal disaccharide absorption requires the bond between the two units to be split by an appropriate intestinal enzyme, such as lactase for lactose or sucrase for sucrose. Limited digestion of a particular sugar can cause bloating or diarrhoea. It does not establish an inability to use every type of sugar.

Digestive enzymes convert many digestible carbohydrates into smaller sugars and ultimately absorbable monosaccharides. A single-unit sugar does not need a bond between sugar units to be split before absorption, but its uptake still has limits and specific conditions. Digestion, absorption and muscle utilisation are related but distinct steps.