Soluble and Insoluble Fiber

Soluble and Insoluble Fiber

Diana Mirkin

Fiber is the structural material of plants and is found in all 
fruits, vegetables, whole grains, beans, nuts and other seeds. It is 
a type of carbohydrate that your body cannot break down, so you 
can't absorb it. There are two types: soluble and insoluble. 
Insoluble fiber adds bulk to your stool and helps to prevent 
constipation. Soluble fiber binds to fat in the intestines and keep 
some fat from being absorbed.

Insoluble fiber may help to prevent colon cancer by speeding 
cancer-causing agents through the digestive system. It helps with 
weight control because it binds to water, creating bulk that makes 
you feel full. It can help control diabetes because it slows the 
rate at which your body absorbs glucose. 

Soluble fiber has an added benefit. When you add more soluble fiber 
to your diet, it lowers blood levels of the plaque-forming LDL 
cholesterol. Soluble fiber is degraded by bacteria in the colon to 
form types of fatty acids that are absorbed into the bloodstream and 
help to block the synthesis of cholesterol by the liver. This is the 
only food component we know will lower blood cholesterol when you 
add more to your diet. However, people who have high blood levels of 
cholesterol must do a lot more than just add soluble fiber to their 
diet. They also should not smoke, not be overweight, and exercise 

You should eat at least 30 grams of fiber per day, and the average 
North American gets only 11 grams. There's very little fiber in the 
typical diet of hamburgers, pizza, fried chicken and coke. Foods 
made from animal products never have any fiber, and processed foods 
made from grains, vegetables or fruit frequently have most of the 
fiber removed. Wheat berries, baked potatoes, apples and oranges 
contain many times more fiber than bread, potato chips, apple jelly 
or orange juice. 

Don't worry about whether you are getting soluble or insoluble 
fiber; you need both kinds, and both are found in fruits, 
vegetables, whole grains and beans. If you're not getting enough 
fiber, don't try to correct the situation by adding fiber 
supplements, lots of bran cereal or foods made with added ground-up 
fiber. When you eat whole fruits, vegetables, whole grains and 
beans, you get all of the vitamins, minerals and phytochemicals 
nature packages with the fiber. Introduce more high-fiber whole 
foods into your diet gradually to avoid digestive discomfort. 

Checked 3/1/07