Insoluble fibre
What it is and what it does
- Cellulose, the main structural part of plant cell walls, is an unbranched chain of several thousand glucose units. (FAO/WHO (1998). Carbohydrates in human nutrition. Report of a Joint FAO/WHO Expert Consultation (Rome, 14-18 April 1997). FAO Food and Nutrition Paper 66, Annex 2 - Dietary carbohydrate composition)
- Lignin, a non-carbohydrate part of the plant cell wall, is also often counted as dietary fibre. (FAO/WHO (1998). Carbohydrates in human nutrition. Report of a Joint FAO/WHO Expert Consultation (Rome, 14-18 April 1997). FAO Food and Nutrition Paper 66, Chapter 1 - The role of carbohydrates in nutrition)
- The Indian food tables (IFCT 2017) report total, soluble and insoluble dietary fibre for each food, measured by the enzymatic-gravimetric method AOAC 991.43. (ICMR-NIN. Indian Food Composition Tables 2017 (Longvah T et al.))
- Insoluble fibre adds bulk to the stool and helps food move more quickly through the stomach and intestines. (MedlinePlus Medical Encyclopedia (US National Library of Medicine): Fiber (review date 7/22/2026))
- Human digestive enzymes do not digest cellulose to any extent. (FAO/WHO (1998). Carbohydrates in human nutrition. Report of a Joint FAO/WHO Expert Consultation (Rome, 14-18 April 1997). FAO Food and Nutrition Paper 66, Annex 2 - Dietary carbohydrate composition)
- In the colon, undegraded fibre residues can trap water within their structure, giving greater bulk. (FAO/WHO (1998). Carbohydrates in human nutrition. Report of a Joint FAO/WHO Expert Consultation (Rome, 14-18 April 1997). FAO Food and Nutrition Paper 66, Annex 2 - Physiological effects of dietary fibre)
- In the original split, insoluble fibres were those slowly and incompletely fermented, with a larger effect on bowel habit. (FAO/WHO (1998). Carbohydrates in human nutrition. Report of a Joint FAO/WHO Expert Consultation (Rome, 14-18 April 1997). FAO Food and Nutrition Paper 66, Chapter 1 - The role of carbohydrates in nutrition)
Why it matters
- EFSA based its fibre intake value on bowel function, judged the most suitable criterion. (EFSA (2017). Dietary Reference Values for nutrients: Summary report. EFSA Supporting Publications 2017:e15121 (doi 10.2903/sp.efsa.2017.e15121); sections 3.2 Carbohydrates and dietary fibre, 3.3 Fats, 3.5 Water)
- FAO/WHO notes it is very difficult to generalise about fibre's effects in the body from fibre analysis alone. (FAO/WHO (1998). Carbohydrates in human nutrition. Report of a Joint FAO/WHO Expert Consultation (Rome, 14-18 April 1997). FAO Food and Nutrition Paper 66, Annex 2 - Physiological effects of dietary fibre)
- FAO/WHO recommended that the terms 'soluble' and 'insoluble' fibre be gradually phased out. (FAO/WHO (1998). Carbohydrates in human nutrition. Report of a Joint FAO/WHO Expert Consultation (Rome, 14-18 April 1997). FAO Food and Nutrition Paper 66, Chapter 6 - Recommendations)
- Too much too fast: adding fibre to the diet slowly, not all at once, helps reduce gas or diarrhoea. (MedlinePlus Medical Encyclopedia (US National Library of Medicine): Fiber (review date 7/22/2026))
General information, not medical advice — for your own needs, ask a doctor or dietitian.
How much is needed
| Who | Amount | What the figure is | Whose figure |
|---|---|---|---|
| India, all groups | no value set | No ICMR-NIN 2020 value | ICMR-NIN 2020 |
| Adult man, sedentary (TOTAL dietary fibre, context) | 30 g/day | AI for total dietary fibre (no separate value for this fraction) | ICMR-NIN 2020 |
| Adult woman, sedentary (TOTAL dietary fibre, context) | 25 g/day | AI for total dietary fibre (no separate value for this fraction) | ICMR-NIN 2020 |
| Adults (TOTAL dietary fibre, context) | 25 g/day | Adequate Intake for total dietary fibre (EFSA sets no separate insoluble-fibre value) | EFSA (EU, not an Indian value) |
| Everyone older than 10 years (TOTAL dietary fibre, context) | at least 25 g/day of naturally occurring dietary fibre | WHO advice for total fibre (no separate insoluble-fibre value) | WHO (not an Indian value) |
India’s own figure (ICMR-NIN 2020) comes first. Figures from other bodies are shown only where they help, and say whose they are.
Sources: ICMR-NIN Expert Group. Short Report of Nutrient Requirements for Indians: Recommended Dietary Allowances and Estimated Average Requirements - 2020; EFSA (2017). Dietary Reference Values for nutrients: Summary report. EFSA Supporting Publications 2017:e15121 (doi 10.2903/sp.efsa.2017.e15121); sections 3.2 Carbohydrates and dietary fibre, 3.3 Fats, 3.5 Water; WHO fact sheet: Healthy diet (26 January 2026)
In every millet and pseudo-cereal, per 100 g raw
| Grain | Amount | Source |
|---|---|---|
| Quinoa | 10.21 g | IFCT A009 |
| Ragi (finger millet) | 9.51 g | IFCT A010 |
| Bajra (pearl millet) | 9.14 g | IFCT A003 |
| Jowar (sorghum) | 8.49 g | IFCT A005 |
| Rajgira (amaranth) | 5.8 g | IFCT A002 |
| Little millet | 5.45 g | IFCT A016 |
| Kodo millet | 4.29 g | IFCT A017 |
Each grain has ONE source, named on its page: IFCT = Indian Food Composition Tables 2017 (ICMR-NIN) with its food code; USDA FDC; FAO WAFCT 2019; NIN 2007 via ICAR-IIMR. Values exactly as printed, not converted — tables differ in method, so compare within a source. Published values for the grain, not a laboratory test of our packs.
Absorption and food
- When cereal grains are milled into refined flour, the outer layers are removed and total fibre falls; the fall is due mainly to a loss of insoluble fibre. (FAO/WHO (1998). Carbohydrates in human nutrition. Report of a Joint FAO/WHO Expert Consultation (Rome, 14-18 April 1997). FAO Food and Nutrition Paper 66, Annex 2 - Effects of food processing on dietary carbohydrates)
- A loss of insoluble fibre has also been reported when wheat flour is autoclaved (pressure-heated). (FAO/WHO (1998). Carbohydrates in human nutrition. Report of a Joint FAO/WHO Expert Consultation (Rome, 14-18 April 1997). FAO Food and Nutrition Paper 66, Annex 2 - Effects of food processing on dietary carbohydrates)
- Peeling fruits and vegetables reduces the fibre you get from them. (MedlinePlus Medical Encyclopedia (US National Library of Medicine): Fiber (review date 7/22/2026))
- Insoluble fibre is found in foods such as wheat bran, vegetables and whole grains. (MedlinePlus Medical Encyclopedia: Soluble vs. insoluble fiber (review date 8/25/2026))
- Whole-grain flours all contain considerable amounts of cellulose. (FAO/WHO (1998). Carbohydrates in human nutrition. Report of a Joint FAO/WHO Expert Consultation (Rome, 14-18 April 1997). FAO Food and Nutrition Paper 66, Annex 2 - Effects of food processing on dietary carbohydrates)