Fibers: why are they essential?

Verified on 12/21/2023 by PasseportSanté

Dietary fibers are complex sugars that are not digested by our body or absorbed. They therefore have no nutritional value but nevertheless have multiple health benefits! Fiber promotes satiety, facilitates transit and has a protective effect against many diseases. But, then, where can you find fiber and what are its benefits? Zoom on the fibers.

Fiber, what is it?

Dietary fibers are complex sugars that occur naturally in plant foods and are not digested or absorbed by the digestive system.

Functional fibers

There is another type of fiber called functional fibers which are actually carbohydrates that have been isolated, extracted and/or purified.

To be part of the range of functional fibers, they must exert beneficial effects on the body. Functional fibers are not absorbed or digested by the digestive system in the same way as other dietary fibers.

The role of fiber

Fiber has different roles to play at the physiological level including the regulation of gastrointestinal function, the reduction of cholesterol levels as well as the management of glycemia (blood sugar levels).

They also contribute to the feeling of satiety which helps with weight management by reducing energy intake. There are many studies on this subject, most claiming that adequate fiber intake protects against Colon Cancer.

There are two types of fiber in plant foods:

soluble (viscous) fibers, which have the property of reducing blood glucose and cholesterol levels;
insoluble fibers which increase the volume of stools in order to regulate intestinal function.

Most plant foods contain both types of fiber. However, the amount of each type of fiber varies between foods.

Foods predominantly insoluble fiber	Foods predominantly soluble fiber
Wheat bran and wheat cereals	Psyllium and enriched cereals
Whole grains and derivatives	Oat bran and oatmeal (oatmeal)
Vegetables: cauliflower, kale, green peas, spinach, turnip, green beans	Legumes: red beans, peas
Fruits: raspberries, apple, pear, banana, blueberries, strawberries	Fruits: orange, grapefruit, mango, dried prunes
Nuts and seeds: almonds, peanuts	Vegetables: asparagus, Brussels sprouts, carrots, onion
Legumes in general	Barley

Foods rich in fiber

The main sources of fiber are vegetables and fruits as well as grain products, legumes and nuts.

Food	Portions	Quantities (g)
Cooked legumes	250ml (1 cup)	12 – 17
Breakfast cereal, 100% wheat bran	30 g (1 oz)	10
Soy beans, fresh (edamame), boiled	250ml (1 cup)	8
Raspberries	125ml (1/2 cup)	4-6
Boiled artichoke	1 medium (120 g)	5
Dried prunes, cooked	75 ml pitted (80 g)	5
Pear with skin	1 medium (166 g)	5
Green peas, cooked	125ml (1/2 cup)	4-5
Blackberries	125ml (1/2 cup)	4
Canned pumpkin	125ml (1/2 cup)	4
Dried dates or figs	60ml (1/4 cup)	4
Potato with skin, baked in the oven	1 medium (150 g)	4
Boiled spinach	125ml (1/2 cup)	4
Almonds roasted in oil or dry	60ml (1/4 cup)	4
Boiled sweet potato	1 medium (151 g)	4
Apple with skin	1 medium (138 g)	3
Winter squash, cooked	125ml (1/2 cup)	3
Papaya	1/2 fruit (153 g)	3
Brussels sprouts, cooked	4 choux (84 g)	3
Blueberries	125ml (1/2 cup)	2-3

Tips for increasing your fiber intake

To increase your fiber consumption, it may be interesting to:

replace refined grain products with brown rice, whole-wheat pasta or whole-wheat bread;
eat more fruits containing fiber: apples and pears with their skins, raspberries and blackberries, dried fruits (prunes, apricots and dates);
choose vegetables rich in fiber more often: artichokes, peas, beets, carrots, broccoli, cabbage, Brussels sprouts, corn, turnips, potatoes with the peel;
eat legumes more often, excellent sources of dietary fiber: white or red beans, lentilslima beans, chickpeas;
add lentils or dried beans to soups, stews and salads. Cook vegetarian chili;
spread hummus on a slice of fiber-rich wholemeal bread as a snack;
as a snack, choose high-fiber cereals (4 g of fiber per serving or more) or a homemade high-fiber muffin;
When making muffin and cake recipes, replace white flour with whole wheat flour. Add ground flaxseed or wheat or oat bran;
add wheat or oat bran, flax or chia seeds to your yogurts and compotes;
add soy beans to soups, stir-fries or salads;
as a snack, eat a small handful of dried fruits and nuts;
read food labels and choose breads, bagels, pitas, tortillas and cookies that contain 2 to 4 g of fiber per serving.

Noticed

It is very important to increase your fiber intake gradually and drink plenty of water to avoid certain gastrointestinal symptoms.

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Daily Fiber Needs

Total fiber requirements have been established based on an intake which, according to scientific data, constitutes protection against cardiovascular diseases and diabetes.

Age	Recommended intakes
Babies 0 – 6 months	ND
Babies 7 – 12 months	ND
Children 2-5 years old	15 g
Children 5 – 11 years old	20 g
Children 11-16 years old	25 g
Teenagers 17 and over	30 g
Adults	25 to 30 g
Pregnant and lactating women	30 g

Potential fiber interactions

A very high fiber intake could harm the absorption of different nutrients including calcium, magnesiumiron and zinc.

However, when there is no deficiency of these nutrients in the diet, adequate fiber intake does not appear to compromise stores of these nutrients.

Fiber deficiency and excess: what are the effects?

Fiber deficiency

Since fiber is not an essential nutrient, low intake does not cause deficiency symptoms. However, insufficient fiber intake can lead to constipation due to low fecal volume.

Excess fiber

Excessive fiber intake has no harmful effects apart from certain gastrointestinal symptoms such as bloating or gas. Overconsumption is very unlikely.

The dietician’s opinion

Dietary fiber is essential for the proper functioning of the body and, when consumed in sufficient quantities, can help prevent many ailments: digestive disorders, digestive cancers, hyperglycemia, etc. To easily increase your daily fiber intake, simply replace breads and refined products with whole foods and stock up on fruits and vegetables at each meal! Don’t forget to drink enough water, i.e. 1.5 to 2L per day, to optimize the benefits of fiber.