Fibre and Your Gut

Fibre passes through the gut almost without being absorbed, and yet it is one of the things your gut needs most.

Fibre is the part of a plant that your body cannot digest. That may sound useless, but it is precisely because it travels almost the whole length of the gut that it does so much: holding water so that stools stay soft, feeding the helpful bacteria, slowing down sugar absorption and carrying some cholesterol out with it.

Two kinds of fibre, two jobs

Soluble fibre dissolves in water and forms a gel. It makes a meal digest more slowly, helps you feel full for longer, contributes to lowering cholesterol and softens the blood sugar peak after eating. There is plenty of it in oats, beans and pulses, apples, oranges, carrots and sweet potatoes.

Insoluble fibre adds bulk to the stool and keeps the bowel moving more regularly. There is plenty of it in rice bran, leafy vegetables, fruit skins and wholegrains.

You do not need to count the two separately. Eat a variety of vegetables, whole fruit, beans and grains that still have their bran, and you will get both without trying.

How to get enough

• Swap part of your white rice for brown rice, sweet potato, corn or oats
• Vegetables at both main meals, favouring leafy greens and colourful root vegetables
• Eat whole fruit rather than juicing it, because juicing throws away most of the fibre
• Add beans and pulses to soups, congee and stews a few times a week
• Keep the skin on fruit that can be eaten with the skin, after washing it thoroughly

Fibre and the bacteria living in your gut

Your large intestine is home to a great many bacteria. They ferment fibre and produce substances that benefit the lining of the gut. The more varied the plants in your diet, the richer that community of bacteria becomes. Fermented foods such as yoghurt and pickled cabbage, in moderation, add to the picture as well.

When to see a doctor

See a doctor if your bowel habits change for more than a few weeks, if constipation or diarrhoea persists, if you have frequent stomach pain, or a lot of bloating.

See a doctor sooner still if there is blood in your stool, if your stool is black, if you lose weight for no clear reason, if you are anaemic, or if someone in your family has had bowel cancer. People with inflammatory bowel disease, a narrowing of the bowel, or who have just had digestive surgery need a specific diet as directed by their doctor.

This information is for general reference only and does not replace advice from your doctor.

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