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Fibre: Why do we need it?

Written by Andrea Ho

Fibre has so many health benefits other than simply keeping our bowels regular. It slows digestion and keeps us feeling full for longer, helps with portion control and weight management, and keeps our blood sugar under control. For heart health, fibre specifically helps with controlling our blood pressure and lowering our cholesterol and triglyceride levels.

But, what is fibre?

Fibre is a carbohydrate that’s only found in plant-based foods – fruits, vegetables, legumes, grains, and nuts. But unlike other carbohydrates like sugars that get absorbed into our bloodstream, fibre simply passes through our digestive tracts. Even though our bodies don’t digest fibre, we still get something out of it!

What’s the difference between soluble and insoluble fibre?

Fibre is broken down into two different types: soluble and insoluble. Each of them plays an important role in helping to prevent disease and promote good health.

Soluble fibre

Soluble fibre absorbs water and turns into a gel-like substance as it goes through our digestive systems. This helps slow digestion and softens your stool so it goes through your gastrointestinal tract more easily. But that’s not all: Soluble fibre helps to lower LDL cholesterol, triglycerides, and total cholesterol. It also helps to control your blood pressure and blood sugar levels.

Foods that are rich in soluble fibre include legumes (beans and peas), oat bran, barley, quinoa; vegetables such as artichoke, squash, broccoli, carrots; and fruits that are rich in pectin, like apples, pears, berries, and bananas. It’s also found in psyllium, a common fibre supplement.

Insoluble fibre

Insoluble fibre doesn’t absorb water or dissolve. Instead, it passes through the body in almost the original form it goes in! This added bulk (or “roughage”) helps to keep our bowels regular and prevent or relieve constipation. Insoluble fibre is found in whole-grain foods, brown rice, nuts, seeds, and colourful fruits and veggies (ones that are yellow, orange and red; or have dark leafy greens).

How much fibre do we need?

In Canada, women need 25 grams of fibre per day and men need 38 grams of fibre per day, but most Canadians only get half of that amount. Foods that contain 4 grams or more of fibre per serving are good sources of fibre.

Remember, serving sizes vary based on the foods you eat, so check out the Nutrition Facts table and review the chart below to see how your favourite foods measure up in fibre content.

Food               One Serving Fibre (grams)
General Mills Fibre 1TM 30g 13.4
Kellogg’s All Bran Buds® 30g (1/3 cup) 11.2
Bran flakes 30g (½ cup) 4.6-5.0
Oatmeal, cooked, large flakes 175mL (¾ cup) 2.8-3.5
Corn Flakes 30g (1 cup) 1.0-1.3
Whole grain, with seeds and bran 1 slice 4.1
Multigrain 1 slice 2.7
Whole wheat, 100% 1 slice 2
White 1 slice 1.2
Spaghetti, multigrain, cooked 125mL (½ cup) 6.0
Quinoa, cooked 125mL (½ cup) 2.6
Brown Rice, long grain, cooked 125mL (½ cup) 1.5
Spaghetti, white, cooked 125mL (½ cup) 1.3
White rice, long grain, cooked 125mL (½ cup) 0.4
Hummus 175 mL (¾ cup) 10.9
Kidney beans, cooked 175 mL (¾ cup) 8.4
Lentils, cooked 175 mL (¾ cup) 6.2
Chickpeas, cooked 175 mL (¾ cup) 5.5
Nuts and Seeds
Flaxseed, ground 30mL (2 tbsp) 3.9
Almonds, unroasted, unsalted 60mL (¼ cup) 3.6
Peanut butter, natural 30mL (2 tbsp) 2.5
Walnuts, unroasted, unsalted 60mL (¼ cup) 1.7
Apple, skin-on 1 medium 4.9
Berries, frozen 125mL ( ½ cup) 2.0-4.6
Blackberries 125mL ( ½ cup) 4.0
Dried prunes, no sugar added 60mL (¼ cup) 3.6
Orange 1 medium 2.3
Banana 1 medium 2.1
Blueberries 125mL ( ½ cup) 2.0
Dried apricots, no sugar added 60mL (¼ cup) 1.6
Green peas, cooked 125mL ( ½ cup) 3.7
Sweet potato, cooked 125mL ( ½ cup) 3.5
Corn on the cob 1 medium 2.8
Carrots, cooked 125mL ( ½ cup) 2.2
Broccoli, cooked 125mL ( ½ cup) 2.0
Rapini, cooked 125mL ( ½ cup) 1.8
Potato, cooked, skin on 125mL ( ½ cup) 1.5
Bell peppers, cooked 125mL ( ½ cup) 1.4
Kale, raw, chopped 125mL ( ½ cup) 0.9
Lettuce, raw chopped 125mL ( ½ cup) 0.3

Source: Canadian Nutrient File Database

About the author

Andrea Ho

Andrea is a registered dietitian with the Schulich Heart Program at Sunnybrook Health Sciences Centre.

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