You’ve probably heard many times how important a high fibre diet is for your health; how traditional cultures which eat a diet high in unrefined foods have lower incidence of bowel problems and bowel cancer. But do you know what that fibre is actually doing for you? Its not just taking up space; when you understand how its helping, you might start deliberately searching out new sources of fibre.

There are many different types of fibre, but two main classifications – soluble and insoluble. Both are useful, in different ways.

The soluble type, as its name implies, tends to soak up materials and carry them out of your body. Your liver, which has dissolved toxins in bile, relies on the soluble fibre to soak up the bile and carry it out of your body. Otherwise, the bile is re-absorbed and your liver has to process it again. Without enough soluble fibre in your diet a nasty pattern of toxin recycling can develop, leaving you feeling like you’re carrying around your own personal rubbish dump.

Fortunately, soluble fibre will also soak up excessive fat in your diet, and reduce its absorption. The right amount of soluble fibre in your diet will help prevent high blood fat and cholesterol levels. That’s why the Mediterranean diet, which is higher in good fats but also higher in fibre from vegetables and legumes, is regarded as one of the healthiest.

The insoluble type of fibre can’t be broken down by our bodies – we don’t possess the enzymes to do it. But we all have bacteria living in our intestines that will happily digest and ferment a great deal of the insoluble fibre.

Your resident colon-dwelling bacteria break down the fibre into short chain fatty acids, which actively feed the cells lining your bowel well. Keeping these cells well fed is very important, as they have the job of transporting nutrients into your bloodstream. The presence of the right amount of short chain fatty acids also alters your bowel pH. That has some important flow-on effects as well. The right pH makes it easier to for your body to absorb important minerals like iron, zinc, magnesium and calcium. The right pH also makes life difficult for pathogenic (disease producing) bacteria to thrive.

The best sources of fibre come from unrefined foods. Legumes like chick peas, black eyed beans, kidney beans contain a mix of soluble and insoluble fibre, and they’re naturally gluten-free. Oats and fruit are excellent sources of soluble fibre. Wheat or rice bran is a great source of insoluble fibre – but is best eaten as part of a food (like bread or breakfast cereal) as some people find its too ‘scratchy’ for their digestion on its own. Vegetables are a fabulous source of fibre, and most of us don’t eat anywhere near enough of them.

Check your diet today for fibre content: Did you eat some legumes? Five serves of vegetables and two serves of fruit? Its not just taking up space – its keeping you healthy.