How to provide soluble and insoluble fiber in your diet?

Dietary fibers are complex carbohydrates long chains of plant origin. According to ANSES (National Food Safety Agency), they may or may not be associated in the plant with lignin or other non-carbohydrate constituents (polyphenols, waxes, saponins, cutin, phytates, phytosterols, etc.). In addition, dietary fiber has the particularity of not being digested by digestive enzymes. Therefore, they cannot be absorbed by our intestine. As a result, they are partly fermented in the colon by colonic bacteria. Once fermented, dietary fiber produces short-chain fatty acids (SCFAs) and gases. These SCFAs are responsible for many beneficial roles in the body. According to ANSES, they can be considered dietary fiber if they have at least one of the following characteristics:

• Increased stool production

• Stimulation of colonic fermentation

• Reduction in fasting cholesterol

• Decrease in blood sugar and/or postprandial insulinemia

Furthermore, dietary fiber includes fiber soluble and fiber insoluble. The latter differ by their degree of solubility. As the name suggests, soluble fiber can solubilize in water and form a viscous gel in the stomach. Conversely, insoluble fibers cannot solubilize and they swell on contact with water. Each of these fibers has its own roles and which are obviously beneficial for our health. For example, soluble fiber helps limit diarrhea and insoluble fiber helps fight constipation.

In France, daily fiber consumption is recommended at 25-30 g by ANSES by ensuring that you include both soluble and insoluble fiber in your diet. However, since the 20th century, the consumption of dietary fiber has declined relatively. The main causes are a diet low in fiber and a preponderance of refined foods (white rice, white bread, white pasta, etc.). Indeed, the NutriNet-Santé study (2012) reveals that the average fiber consumption is 18 g/day among women compared to 20 g/day among men. Additionally, it is estimated that only one in 5 men and one in 10 women achieve the recommended amount of fiber. A diet low in fiber is not without consequences for our health. It is the cause of atrophy of the intestinal mucosa, digestive discomfort and multiple diseases (including colorectal cancer).

Fruits and vegetables, legumes, oilseeds as well as brans and sprouts contain soluble and insoluble fiber. However, the content of soluble and insoluble fiber varies depending on the food. It is advisable to have a diversified diet allowing you to vary the sources of dietary fiber.

	Food (100g)	Total fiber (g)	Soluble fiber (g)	Insoluble fiber (g)
Fruits	Raspberry  Currant  Blackberry Dried prune  Dried apricot  Date  Coconut  Dried fig	3.1 3.5 5.7 6.1 8.1 8.7 9 10.3	0.5 0.5 0.6 2.6 3.6 1.2 2.1 1.4	2.6 3 5.1 3.5 4.5 7.5 6.9 8.9
Vegetables	Broccoli Carrot  Green cabbage  Leek  Eggplant  Lawyer	3.2 3.2 3.3 3.4 3.5 5.1	0.7 1.3 0.3 0.2 1.2 1.9	2.6 1.9 3 3.2 2.3 3.2
Legumes	Split peas Lenses Red beans	6 9.1 10.4	0.5 0.3 1.5	5.6 8.8 8.9
Oilseeds	Brown  Chestnut  Hazelnut  Almond	5.7 5.7 7.3 10.7	0.4 0.4 0.3 0.4	5.3 5.3 6.9 10.3
Germ	Wheat germ	14.5	0.9	13.6

Breakfast :

• A hot drink (coffee, tea, herbal tea)
• 50g oatmeal
• A bowl of milk
• An Apple

Lunch :

• 100 g of tomatoes in salad
• 100 g of chicken breast
• 200 g cooked brown rice
• 100 g cooked carrots
• A slice of wholemeal bread
• 30 g of Camembert
• A pear

Snack : 

• A handful ofalmonds (15 g)
• 10 g of prunes

Dinner : 

• 100 g of cucumbers in salad
• 100 g of cod fillet
• 200 g wholemeal pasta
• 100 g spinach
• A white cheese

This standard menu allows you to provide 33 g of fiber in a day.

• Eat 5 fruits and vegetables per day to stock up on fiber. We preferably choose fresh, organic and seasonal fruits and vegetables, while taking care to preserve the skin.

• Eat fruits and vegetables raw. Cooking loses a lot of the fiber contained in these foods.

• Prefer products complete (wholemeal pasta, wholegrain rice, wholemeal flour, etc.) compared to white products which are very low in fiber.

• Increase your meals based on legumes depending on their digestibility. They have interesting nutritional qualities due to their richness in proteins, vitamins and minerals as well as fiber.

• Consume a daily handful oilseeds, the equivalent of 15 g. These can be introduced into salads, yogurts or breakfast cereals.

• Add gradually add fiber to your diet (5 g in 5 g per day), especially if you go from a low to high fiber diet. Otherwise, they can cause abdominal pain, bloating, gas, constipation or diarrhea.

• Drink water as your fiber intake increases. A good fluid intake helps ensure the functioning of fiber in the body.