Dietary fibre can be soluble or insoluble, and ideally we should have both kinds in our diet, and they can be obtained quite easily since they are present in all plant foods, although in varying quantity. Soluble fibre is processed and fermented in the intestine, with a number of healthy results. Soluble fibre lowers cholesterol and triglyceride levels, and by slowing the absorption of sugar from the digestive tract, can stabilize blood sugar. Many forms of this kind of fibre help with both constipation and diarrhoea. Pectin, found in apples, strawberries and citrus fruit, as well as oat bran are very good in lowering cholesterol and triglycerides. Insoluble fibre does not have such a variety of actions, but it does attract water, which causes it to swell and form bulk, and consequently reduce constipation and lessen transit time through the intestines. As it passes through the body, it absorbs toxins from food, reduces the production of bacterial toxins in the intestines, and by "cleaning out" the stomach can reduce the incidence of colon cancer. We can find this kind of fibre in celery and the skins of fruit and vegetables, as well as wheat bran. The American Dietetic Association recommends 20 to 30g of fibre every day for adults, but in industrialized countries we often consume half the recommended amount. A diet rich in fruit and vegetables, with the addition of varied whole cereals and a selection of pulses and nuts can provide all the fibre we need, but if healthy eating is not always possible, a fibre supplement may be helpful at times.
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