The human body is not able to degrade and digest dietary fibre. But it is easily digested (fermented) by intestinal bacteria, which may result in the development of gases that cause bloating and abdominal pain.
The soluble form of dietary fibre is found primarily in legumes (beans, peas, soya, lentils), fruit (citrus, apricots, blackberries, blueberries, raisins, prunes), vegetables (artichokes, cabbage, cauliflower, broccoli, Brussels sprouts, onions), oat bran and barley. Soluble fibre dissolves in water and forms a gel-like structure. The insoluble form of dietary fibre is found primarily in wholemeal or black bread, wholemeal rolls, wholemeal pasta, brown rice, vegetables (carrots, tomatoes, peppers, potatoes, courgettes, cucumbers), fruit (apples, pears, figs, kiwi fruit, bananas, wild strawberries), nuts and seeds. Insoluble dietary fibre helps to reduce diarrhoea, while in the case of constipation it is desirable to increase the amount of soluble fibre in order to loosen the faeces and facilitate bowel movements.