Fibre

Definition

All dietary components that are not digested by enzymes in the digestive tract (the stomach and small intestine) fall into the category of dietary fibre.
Fibre primarily consists of plant components: cellulose, hemicellulose, pectins, lignins, gums, alginates, carrageenans, resistant starches.
Fibre can be classified as insoluble fibre (cellulose, lignin, certain hemicelluloses) and soluble fibre (certain hemicelluloses, glucans, pectins, gums, seaweed fibres).
Fibre can have a range of physiological and metabolical effects depending on whether it is soluble or insoluble.
Certain forms of fibre can be fermented by bacteria in the colon.

Role in the body

Insoluble fibre:

  • Promotes intestinal transit by increasing the production of stools and stimulating colonic fermentation.
  • Fibre plays a role in fighting constipation.

Soluble fibre:

Sources in vegetables and other foods (Source: Ciqual)

Foods with the highest content of fibre

g/100g

Dried prunes, almonds

15-16

Stoned/pitted dried apricot

13.7

Oatmeal, crisps/chips

10

Cooked artichoke

9.4

Cooked red beans, cooked chickpeas, peanuts, currants, cooked white beans, canned salsify

8-9

Cooked lentils, dried dates, hazelnuts, black currants, wholegrain bread

7-8

Raspberries, raisins, cooked broad beans, chestnuts, parsley, cooked peas, mulberries, walnuts

6-7

Jerusalem artichoke, raw celery root, canned flageolet beans

5

Cornflakes, cooked split peas, Brussels sprouts, rusk, green olives, semolina

4-5

Cooked yams, cooked parsnips, raw dandelion, raw fennel, cooked spinach, cooked French/green beans, baguette, country bread

3-4

Raw sweet potato, cooked green cabbage, gherkins, cooked broccoli, cooked leeks, raw carrots, cooked cauliflower, raw cress, raw button mushrooms, raw chicory, raw Chinese okra, canned sweet corn,
canned soja bean, cooked turnip, cooked aubergine/eggplant, cardoon, raw celery, raw red pepper, raw green pepper, cooked pumpkin

2-3

Recommended intake

There is no official RDA (Recommended Daily Amount) for fibre. However, a value of at least 25 g per day is used as a recommendation. The RNAs (Recommended Nutritional Allowances) are given for the French public by age bracket in g/day  

Age bracket

RNA in g/day

Children

Age + 5 g
Example: a 10-year-old child = 15 g of fibre

Adults

25 - 30 g

Deficiencies / Excess

Average daily fibre intake in France is estimated at between 15 and 22 g, which is inadequate. 50% of this intake is derived from grain-based foods, 32% from vegetables, 16% from fruit and 3% from dried vegetables. Excessive fibre intake is not toxic. However, consumption of too much fibre (especially fibre that ferments rapidly upon reaching the colon) can have undesirable side effects such as flatulence, bloating and diarrhea.

Disadvantage

Some forms of fibre are more difficult to digest and can produce intestinal irritation in those who are most sensitive. If this is the case, preference should be given to fruits and cooked vegetables, since cooking softens fibre and makes it more digestible.

Tips / advice from the nutritionist

Vary your sources of fibre: fibre has different characteristics depending on the type of food. Grain-based products primarily provide insoluble fibre, which has benefits for intestinal transit. The more grains are refined (and therefore become less whole), the lower their fibre content. About one third of the fibre in fruits and vegetables is soluble fibre, while approximately one fourth of the fibre in dried vegetables is soluble.

To learn more

Site of the European Food Information Council (EUFIC)