Fiber: Insoluble and Soluble

Fiber contains no calories and is not digestible, therefore it serves primarily as a medium to provide bulk to stool. The distinction that can be made between soluble and insoluble fiber is their ability to absorb and retain water. Soluble and insoluble fiber both attract water, but soluble fiber softens and gels in water while insoluble fiber does not. Think apple and apple peel, the apple’s juicy center is soluble fiber and the apple’s peel is insoluble fiber. For example, if you were to take an apple, peel it, cut it into wedges and dehydrate the peel and the wedges seperately, to rehydrate the wedges would be simple by adding water, but the peel would likely never regain any mass or absorb any of the water. Soluble and insoluble fiber are both important in digestion and overall health. 

Soluble fiber contains many health benefits, and in particular benefits to the heart because it has that ability to bind to cholesterol rich bile in the GI tract forcing this “floating” cholesterol to pass through the stool rather than reabsorbing in the body. Soluble fiber will slow glucose absorption in the intestines by creating bulk and allowing foods to be absorbed more slowly, this in particular is a huge benefit for diabetics and those with hypoglycemia. Insoluble fiber primarily acts as a stool softener decreasing this likelihood of constipation and hemorrhoids. 

The intestines are a muscle! Fiber provides bulk and softness to the stool forcing your intestines to work and move more as it passes through, giving the GI tract muscles exercise and tone throughout the day. Fiber, both soluble and insoluble, decreases transit time allowing a lesser exposure of possible carcinogens in the intestines reducing the risk of colon cancer greatly.  

How much fiber is needed each day and where can it be found? 

The recommended daily intake of fiber is 1.4 grams for every 100 calories consumed in a day.

Fiber is any part of plant-based foods that cannot be digested or absorbed in the body. Foods that contain primarily soluble fiber are fruits, vegetables, legumes and oats. Foods that contain primarily insoluble fiber are whole grains, fruit/vegetable peels or celery “strings”, and root vegetables.  

What foods are considered “high fiber”?

You may notice as you move through the aisles of the grocery store that some foods are labeled “high fiber” or “excellent source of fiber”. These distinctions are made by considering the food to have (at a minimum) 2 grams of fiber for every 100 calories. It is easy to determine for yourself what the fiber return on a food is by looking at the nutrition label and comparing the fiber content to the amount of calories. For example, if a food is 170 calories and contains 34 grams of fiber that would be a “high fiber” food.  

All things in moderation- like anything too much soluble or insoluble fiber can cause negative effects like bloating, gas and too large or too frequent bowel movements.

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