Popeye University: Fiber Uncomplicated

Popeye* · 03-31-2020, 05:29 PM

THE UNCOMPLICATED VERSION

Dietary fiber is a non-digestible carbohydrate found in foods.

There are two broad categories:

Soluble fiber: Dissolves in water and can be metabolized by the "good" bacteria in the gut.
Insoluble fiber: Does not dissolve in water.

KEY POINTS

Consuming adequate amounts of soluble, ferment-able fiber is very important for optimal health because it optimizes the function of the friendly bacteria in the gut.
Some types of fiber can cause weight loss by increasing feelings of fullness, leading to a reduced calorie intake.
Foods that contain viscous fiber have a lower glycemic index and cause smaller spikes in blood sugar than foods that are low in fiber.
Some types of fiber can reduce cholesterol levels. However, most studies show that the effect isn't very large, on average.
The laxative effects of fiber differ. Some reduce constipation, but others increase constipation. This appears to depend on the individual and type of fiber.
Studies have associated a high fiber intake with a reduced risk of colon cancer.

SUMMARY

Dietary fiber has various health benefits. Not only does it feed your gut bacteria, fermentable fiber also forms short-chain fatty acids, which nourish the colon wall. Additionally, viscous, soluble fiber may reduce your appetite, lower cholesterol levels and decrease the rise in blood sugar after high-carb meals. If you are aiming for a healthy lifestyle, you should make sure to get a variety of fiber from whole fruits, vegetables and grains.

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A SIDE NOTE:

Fiber, steroids, and cancer

Kritchevsky D.
Abstract

Fiber is a generic term for dietary components which are not metabolized by intestinal secretions. Fiber encompasses a variety of substances of unique structure having specific physical characteristics and physiological function. There are a number of epidemiological and case-control studies on diet and colon cancer, many of which suggest that dietary fiber or fiber-rich foods may exert a protective action, but the view is not unanimous. One study finds a negative correlation between cancer mortality and pentose-rich dietary fibers. Animal studies have been carried out using rats of different strain, semipurified or commercial diets, and various carcinogens administered in a variety of ways. Again, there is no unanimity. The results depend upon the type of fiber and the route of carcinogen administration. Some type of fiber bind bile acids and salts, and this property has been investigated as a means of explaining the protective action of fiber. Several recent studies in human subjects suggest that susceptibility to colon cancer is related inversely to the concentration of fecal bile acids rather than to the absolute quantity of fecal bile acids or their structure. Future studies require better standardization of protocols so that intradietary effects can be assessed.