Fibre Glossary

Fibre comes with its own vocabulary, much of it borrowed from regulation and food science rather than everyday language. Here are the terms that actually show up on an Australian label or in fibre research, defined plainly, with a link to the fuller explainer where one exists.

Intake and Benchmarks

Adequate Intake (AI): NHMRC's fibre benchmark, set at the median intake associated with normal gut function: 30g a day for men, 25g for women. See how much fibre you need a day.
Suggested Dietary Target (SDT): NHMRC's higher fibre benchmark, set with long-term health in mind: 38g a day for men, 28g for women.
NHMRC: The National Health and Medical Research Council, the body that publishes Australia's Nutrient Reference Values, including the fibre benchmarks above.
Upper Level of Intake (UL): A formal ceiling NHMRC sets for some nutrients where high intake carries a defined risk. There is no UL for dietary fibre. See can you eat too much fibre?

What Fibre Is, by Structure

Dietary fibre: Under the Food Standards Code, a plant-derived or synthetic substance that resists digestion in the small intestine and meets a specific structural test. See the full legal definition.
Soluble fibre: Fibre that dissolves or disperses in water, due to its molecular structure. See soluble vs insoluble fibre.
Insoluble fibre: Fibre that doesn't dissolve in water and largely passes through the digestive system unchanged, adding bulk.
Fermentable: Capable of being broken down by gut bacteria in the large intestine. A separate property from solubility, though the two often correlate.
Degree of polymerisation (DP): The number of sugar units joined together in a carbohydrate chain. Part of the Code's structural test for whether something counts as dietary fibre.
Fructan: A carbohydrate built from chains of fructose units. Inulin and FOS are both fructans.

Common Fibre Ingredients

Resistant dextrin: A manufactured fibre made by treating starch with heat, acid and/or enzymes until it resists digestion. See what is resistant dextrin.
Resistant maltodextrin: Largely interchangeable with resistant dextrin in everyday use; the specific regulatory term used in FSANZ Application A491.
Soluble corn fibre: A resistant maltodextrin made specifically from corn starch. See what is soluble corn fibre.
Psyllium: A soluble, gel-forming fibre from the husk of the Plantago ovata seed. See what is psyllium.
Inulin: A long-chain fructan, usually from chicory root, classified as dietary fibre under the Code. See what is inulin.
FOS (fructo-oligosaccharides): A short-chain fructan, closely related to inulin. See what is FOS.
PHGG (partially hydrolysed guar gum): Guar gum broken down by enzymes to reduce its thickening power while keeping its fibre content. See what is PHGG.

Regulation and Labelling

FSANZ: Food Standards Australia New Zealand, the statutory authority that develops the Food Standards Code.
Food Standards Code: The legal standards covering food labelling, composition and safety in Australia and New Zealand, including the definition of dietary fibre.
AOAC method: A specific, named laboratory analysis method. The Code prescribes which AOAC method applies to which fibre type for label testing.
Excellent source of fibre: A nutrition content claim under Schedule 4 of the Code, requiring at least 7g of dietary fibre per serve. See what fibre claims mean.
Prebiotic: Under the widely used ISAPP consensus definition, a substrate selectively used by host microorganisms that confers a health benefit. See prebiotic vs probiotic.

FODMAP Terms

FODMAP: Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols: short-chain carbohydrates that can be poorly absorbed in some people. See which fibre supplements are low FODMAP.
Low FODMAP certification: A specific laboratory testing and certification process for a finished product, separate from an individual ingredient's general FODMAP status. See what low FODMAP certification tests for.