Health Articles
Everything You Need to Know About Fibre
by Susan Bowerman

Sources of Fibre

Did you know there’s more than one type of dietary fibre? Eating a wide range of plant foods will help you meet all your needs but let’s talk about fibre in detail so that you can really understand the benefits of each type of fibre.

I don’t need to tell you that fibre is important in your diet – you already know that. And, you probably also know that most people don’t eat as much fibre as they should. But what you may not know is that in addition to eating enough fibre, you also need to eat enough of the different types of fibre. That’s because not all fibres function exactly the same way – different types of fibres have different effects on the body. So, just as you should aim to eat a wide range of foods in order to get a wide array of nutrients, a varied diet helps to provide you with enough of the different types of fibres, too.

What is fibre, and How Much do You Need?

Simply put, fibre is the structural component of plant foods, so it’s found in vegetables, whole fruits, beans and grains (like corn or brown rice) – there’s no fibre in meats, fish or poultry.

The average person falls far short of meeting the fibre recommendation of 25-30 grams a day. In fact, most of us only eat about 10 grams a day, which means we may be missing out on the health benefits of dietary fibre. fibre, of course, helps move the digestive process along, but high fibre foods also provide the sensation of fullness, so they help with hunger control. And, certain fibres also support the growth of friendly bacteria in your digestive tract.

If you don’t eat as much fibre as you should, it’s best to gradually increase the amount you eat gradually over a few weeks. Adding too much fibre to the diet in a short period of time might lead to abdominal discomfort and gas, so take it slowly to allow your system time to adjust. Also, drink plenty of liquid to allow the fibre to soften and swell.

Different Types of fibre: What Are They and What Do They Do?

There are two broad classes of dietary fibre -– soluble fibres and insoluble fibres.

Soluble fibres are found in the highest concentration in apples, oranges, carrots, potatoes, oats, barley and beans. As the name suggests, soluble fibres are just that – they dissolve in water. And when these fibres dissolve, they thicken up. If you’ve ever cooked oatmeal at home, you probably noticed that as it cooks, it gets thick and gluey. That’s because the soluble fibre in the oats is dissolving in the liquid, which makes your oatmeal thick and a little bit sticky.

When these fibres come in contact with the liquid in your stomach, they swell up and thicken, too, which is why they help keep you full. Soluble fibre also slows the absorption of glucose (sugar) from the blood stream and so it can help to keep blood sugar levels more even throughout the day. Soluble fibre is also the type of fibre that the healthy bacteria in your lower digestive tract like to feed on, which encourages these friendly bacteria to multiply.

Insoluble fibres also support the health of your digestive system, but in a different way. Insoluble fibres don’t dissolve in water – instead, they simply absorb water in the lower tract, which makes the fibre more bulky. This type of fibre, found in the highest concentrations in vegetables, wheat bran, corn bran, rice bran and most other whole grains, speeds the passage of waste through your digestive system, so it helps to keep you regular.

There’s one other interesting type of fibre, called ‘resistant starch’. When you eat fruits, vegetables, grains and beans, they contain different types of carbohydrates – sugars, starches and fibre. Usually, the starches are broken down into individual sugars during the digestive process – but some simply defy digestion. Beans, bananas and oats are the major sources of these ‘resistant starches’ that deliver some of properties of both soluble and insoluble fibres. Since resistant starch doesn’t break down (and stays more or less intact as it travels through the digestive tract) it traps water, adds bulk and helps with regularity – much like insoluble fibre. But, resistant starch acts like a soluble fibre, too – it offers up a feast to the healthy bacteria that live in your lower intestine, and it may also help blunt rapid rises in blood sugar, much like water-soluble fibres do.

How Can You Tell if a fibre is Soluble or Insoluble?

Maybe you’ve never thought about it, but it’s actually fairly easy to tell the two fibres apart. When you make barley soup or boil potatoes, you can easily see how the liquid thickens up – that’s because barley and potatoes are high in soluble fibre. On the other hand, when you cook brown rice – a whole grain that’s rich in insoluble fibre – it doesn’t get sticky because the fibre doesn’t dissolve. Instead, it simply absorbs water as it cooks, causing the grains to swell up.

Another easy way to see the difference is to open up a can of beans (rich in soluble fibre) and then open up a can of corn – a grain that contains mostly insoluble fibre. Both the beans and the corn are water-packed, but if you take a close look at the liquids in the can, they look very different from one another. Since the corn fibre is insoluble, the liquid that it’s packed in looks watery, rather than sticky or gluey. But the liquid in the can of beans is much thicker, because the water-soluble fibre in the beans has thickened up the water that the beans are packed in.

Tips for Increasing fibre Intake

Written by Susan Bowerman, MS, RD, CSSD, FAND. Susan is a paid consultant for Herbalife.