A Tale of 2 Fibres

How many foods can you name right now that are good sources of fibre? Whole grains, lentils, oats, rye flour, avocados, soybeans, lemons...and wait, did I just say avocados? And soybeans and lemons? I certainly did. You might find it surprising that the last three foods are good sources of fibre! In fact, when most people are asked to think of fibre sources, grain products are usually the first and only to come to mind. What you might also find surprising, is that there are actually TWO kinds of fibre in our foods!

That's right, what we normally call 'fibre' is actually broken down into 'soluble fibre' and insoluble fibre'. Soluble fibre forms a gel in our G.I. tract and is then digested by bacteria in our colon. Soluble fibres are beneficial for their possible roles in lowering blood cholesterol and protecting against heart disease and diabetes. ¹ Foods high in soluble fibres include oats, barley, apples and citrus fruits, and seeds and husks. ²

Insoluble fibres do not form gels in out G.I. tract and therefore the bacteria in our colon cannot digest them like they can soluble fibres. These fibres play vital roles in promoting colon health by bulking up stool and alleviating difficult bowel movements. The best sources for this type of fibre are brown rice, legumes, whole grains, and vegetables such as cabbage, carrots and brussels sprouts. ²


So the next time you thinking about biting into an apple, remember that just one apple alone provides your diet with about 3 grams of fibre!


¹ N.R. Sahyoan and coauthors, Whole-grain intake is inversely associated with metablolic syndrome and mortality in older adults, American Journal of Clinical Nutrition 83 (2006): 124-131; B. M Davy and C.L. Melby, The effect of fiber-rich carbohydrates on features of Syndrome X, Journal of the American Dietetic Association 103 (2003): 86-96.
² E. Whitney, S. Rady Rolfes, The Carbohydrates: Sugars, Starches, and Fibers, Understanding Nutrition (2009): 106-123.