There are several types of fiber that function differently and provide distinctive health benefits.
You may be familiar with the terms "soluble fiber" and "insoluble fiber," but within each category there are many different fibers. Soluble fibers bind with fatty acids and slow digestion so blood sugars are released more slowly into the body. These fibers help lower LDL (bad) cholesterol and help regulate blood sugar levels for people with diabetes. Insoluble fibers help hydrate and move waste through the intestines and control the pH levels in the intestines. These fibers help prevent constipation and keep you regular.
Most Americans get both types of fiber from two sources: Their diet and added “functional” fiber. Dietary fibers are found naturally in the fruits, vegetables, nuts, and grains that we eat. Functional fiber, a growing trend in the food industry, is fiber that has been isolated and extracted from plants or animal sources and added to drinks and food products to boost their fiber content. Both sources offer the same health benefits.
Most nutritionists encourage getting fiber from whole foods that we eat because they contain many other healthful plant compounds. But if you don’t get enough fiber in your diet -- 25 to 38 grams a day is ideal -- added functional fibers can help fill in the gap.
Eating a wide variety of fibers is the ideal solution to gaining all the health benefits. This chart shows the most types of dietary and functional fibers, where they come from, and how they benefit health.
Types of Fiber
|Soluble or Insoluble||Sources||Health Benefits|
|Insoluble||Naturally found in nuts, whole wheat, whole grains, bran, seeds, edible brown rice, skins of produce.||"Nature's laxative": Reduces constipation,lowers risk of diverticulitis, can help with weight loss.|
|Inulin oligofructose||Soluble||Extracted from onions and byproducts of sugar production from beets or chicory root. Added to processed foods to increase fiber.||May increase beneficial bacteria in the gut and enhance immune function.|
|Insoluble||Found naturally in flax, rye, some vegetables.||Benefits heart health and possibly immune function. Use caution if celiac or gluten intolerant.|
|Mucilage, beta-glucans||Soluble||Naturally found in oats, oat bran, beans, peas, barley, flaxseed, berries, soybeans, bananas, oranges, apples, carrots.||Helps lower bad LDL cholesterol,
reduces risk of coronary heart disease and type 2 diabetes. Use caution if celiac or gluten intolerant.
|Pectin and gums||Soluble (some pectins can be insoluble)||Naturally found in fruits, berries, and seeds. Also extracted from citrus peel and other plants boost fiber in processed foods.||Slows the passage of food through the intestinal GI tract, helps lower blood cholesterol.|
|Polydextrose polyols||Soluble||Added to processed foods as a bulking agent and sugar substitute. Made from dextrose, sorbitol, and citric acid.||Adds bulk to stools, helps prevent constipation. May cause bloating or gas.|
|Psyllium||Soluble||Extracted from rushed seeds or husks of plantago ovata plant. Used in supplements, fiber drinks, and added to foods.||Helps lower cholesterol and prevent constipation.|
|Resistant starch||Soluble||Starch in plant cell walls naturally found in unripened bananas, oatmeal, and legumes. Also extracted and added to processed foods to increase fiber.||Helps weight management by increasing fullness.|
|Wheat dextrin||Soluble||Extracted from wheat starch, and widely used to add fiber in processed foods.||Helps lower cholesterol (LDL and total cholesterol), reduces risk of coronary heart disease and type 2 diabetes. Avoid if celiac or gluten intolerant.|