What is the difference between soluble and insoluble fiber ?

What is the difference between soluble and insoluble fiber and why is it important?

Really good question that I am asked often.  

Fiber is an indigestible plant material that the body cannot absorb. Fiber has shown many health benefits that range from digestive health, absorption of key nutrients such as calcium, prevention of colon cancer, glycemic control and lowering of LDL cholesterol. 

Let take a closer look at soluble vs insoluble fiber, great sources, and key benefits: 

Insoluble fiber is a type of fiber that does not dissolve in water and remains intact as it passes through the digestive system.  

Benefits:  insoluble fiber aid to add bulk and attract water to the stools, which can aid in promoting regular bowel movements and preventing constipation.  

Good sources include whole grains, nuts, seeds, and some vegetables. 

Soluble fiber is a type of fiber that dissolves in water to form a gel-like substance in the digestive tract.  

Benefits: soluble fiber aid to slow down digestion and can help regulate blood sugar levels and lower LDL-cholesterol.  

Good sources include oats, fruits like apples and citrus fruits, flax seeds, legumes, and psyllium husk. 

Increasing your intake of both soluble and insoluble fibers can have numerous health such as supporting weight management, reducing the risk of chronic diseases such as cardiovascular disease and diabetes, promoting a healthy gut microbiome, absoprtion of certain micronutrients (such as calcium) and reduce the risk of colon cancers to name just a few. 

Are all prebiotics fibers…and what is the link with the absorption of certain minerals such as calcium? 

Not all prebiotics are fibers – Interestingly though many prebiotics are! 

What is a prebiotic: It is an indigestible part of food that ferments in the gut and fuels the growth of good bacteria of the intestine which in turn produce short chain fatty acids linked to gut health. 

Did you know that foods rich in prebiotic fiber, such as fructans and galacto-oligosaccharides can help the absorption of calcium by stimulating the growth of bifidobacteria and lactobacillus bacteria in our gut? Fibers therefore can play a functional role in our gut’s health that deserves to be recognized! 

How much fiber should I have and is it possible to have too much? 

Adult females who are healthy should aim for 25g fiber and healthy adult men should aim for 38g of fiber. Careful, too much fiber can cause digestive issues such as gas, abdominal discomfort, and bloating.  If you are being followed by a registered dietitian, you should mention these symptoms especially if you have started to increase your intake to discuss useful strategies to manage these symptoms.  

Additionally, water intake is important to reap the benefits of fiber and prevent constipation in relation to increased fiber intake. Like anything else, too much water is not a good thing. A good rule of thumb is 1.5-2L per day for most healthy adults, but each has individual needs that can be determined by your healthcare provider or registered dietitian. 

Here are a 10 great sources of fiber and their fiber content: 

1. Blackberries or raspberries: ½ cup (125ml) provides 4.2g of fiber 
2. Edamame (green soybeans), cooked, 175 mL or ¾ cup, 6g of fiber 
3. Yellow beans, cooked, ½ cup (125ml), 9.7g of fiber  
4. Chia seeds, 1 tbsp (15 ml), 3.7g of fiber 
5. Flax seeds, whole, 1 tbsp (15 ml), 2.9g of fiber 
6. Lentils or garbanzo beans (chickpeas), cooked, 175 mL or ¾ cup, 5.5 of fiber 
7. Kidney beans, dark red, cooked, 175 mL or ¾ cup, 8.4 of fiber 
8. Whole wheat bread, commercial, 1 slice (33g), 2.1g of fiber 
9. Potato, with skin, 1 medium, 3.1 gof fiber 
10. Apple, with skin, 1 medium, 3.5g of fiber  
11. Oats, 1/3 cup dry (30g), 3g of fiber 
12. Artichoke (Globe, French), frozen, boiled, drained, 125ml, 4.1g of fiber.