What is Fibre?

In my last blog “Why do we need carbohydrates?” I briefly spoke about fibre and its benefits. In this blog, I will look at fibre (Or Fiber in the United States) more closely and how it works.

The importance of fibre is something that most everyone agrees upon. Although there are some medical conditions that make it necessary to avoid fibre, fibre helps to keep most of the population healthy. But what exactly is fibre? Where is it found? How much do we need?

What is Fibre?

Fibre is a complex carbohydrate. A complex carbohydrate, is as it sounds, a carbohydrate that has a more complex structure which takes more time for the body to break down. Because of this fibre can slow how long it takes the body to breakdown food which can have many health benefits discussed below. There are two main types of fibre: Soluble and Insoluble.

  • Soluble Fibre – dissolves in water. When consumed the fibre dissolves into the fluid in the stomach and intestines and becomes gel-like. This gel continues to move through the digestive system and is finally broken down by good bacteria in the large intestine. This breakdown can cause gas and is the reason for the old rhyme “beans, beans good for your heart the more you eat them the more you fart”. Good sources are oatmeal and oat bran, legumes, such as dried beans, peas and lentils, and pectin-rich foods such as apples, strawberries and citrus fruit.
  • Insoluble Fibre – does NOT dissolve in water and so stays mostly the same in the stomach and intestines. They instead act as “bulk” which help the body feel full longer (Yes!!). Insoluble fibre also helps form regular, soft bowel movements. Good sources are wheat bran, whole-grain foods, and the skins, leaves and seeds of vegetables and fruit.

It is very important to drink enough fluid when taking fibre. Think of it as a sponge, when wet, it is soft and moves easily, but dry it is quite hard and difficult to move. Better to have a soft sponge moving through the intestines than a hard one!

What are the best sources of fibre?

Fibre can be found in many foods including grains, fruits and vegetables and legumes. When most people think of fibre they think of unrefined grains, such as whole grains like brown rice, barley and oatmeal. Unrefined just means that the grain keeps more nutrition and fibre simply because they are less processed.

Why is this? Let’s look closer at the whole grain. A whole grain is, as it sounds, whole, meaning the grain is in its whole form or ground into a flour without removing any parts of the seed. The seed contains 3 main parts: the bran, the germ and the endosperm. It is these parts together that can provide higher sources of fibre and other important nutrients.

Whole Grain versus Refined Grain

Why is fibre good for us?

Fibre has many important jobs in our body:

  • provides a small amount energy when broken down into its basic forms
  • can slow digestion, which allows better absorption of nutrients as well as better blood sugar control. That is why it is often recommended that diabetics choose whole grains over white/processed grains
  • helps us feel full longer which is called satiety (both types do this)
  • help keep our bowel movements regular
  • fibre may lower risk of heart disease by holding onto fat from our food, preventing further digestion and absorption. This includes cholesterol which is a well-known marker for heart disease risk

Health Canada has recently released its updated Food Guide (https://food-guide.canada.ca/en/) which recommends eating whole grains and limiting foods high in sugar.  The Guide suggests ½ of your plate consist of fruit and veggies, ¼ protein and ¼ whole grains. By doing this you should take in adequate amounts of fibre through a variety of veggies, fruit and whole grains.

When choosing whole grain products try to choose ones with “100% whole grain” or “100% whole wheat” (with the germ if possible) listed at the beginning of the ingredient list. I try to aim for a product that has at least 3grams of fibre per serving when I can. BUT yes I do eat white bread (Often a French baguette with extra virgin olive oil and good balsamic vinegar)! Remember, healthy, enjoyable eating is all about balance.

Can you get too much?

If fibre intake is increased too quickly is can lead to unwanted side effects such as increased gas and potentially some pain from that gas. That is why most doctors and dietitians recommend increasing fibre intake slowly so the body has time to adjust. When in doubt, speak with your doctor or a registered dietitian for a more individualized plan.  Keep an eye out for my next blog where I will provide some easy tips to increase your fibre intake, including high fibre recipes.

Disclaimer:  The above information is intended for general public education and is not intended to be dietetic advice in any respect or to any person. Use of this information does not make any person a direct client of Tanya Brown,RD for any purpose and no such relationship will exist unless a formal client relationship has been entered into. Please consult your Doctor or a Registered Dietitian for individual recommendations prior to making any dietary or lifestyle changes.


Canada’s Food Guide (https://food-guide.canada.ca/en/)

Mahan and Escott-stump. 2004. Krause’s Food, Nutrition and Diet Therapy, 11th Edition. W.B. Sanders Co.

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