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Insoluble or Soluble Fiber: Which Lowers Cholesterol?

Studies Show That Soluble Fiber May Help Lower Cholesterol More


Updated June 03, 2014

There are two types of fiber: soluble fiber and insoluble fiber. While both of these are important to include in your diet, studies have shown that one type of fiber can also help to lower your cholesterol.

We have already known some of the other heatlhy benefits that fiber has to offer. It helps with normal bowel function and it adds bulk to foods to make you feel fuller. However, there is evidence of another, essential benefit that fiber may have is that it can improve your heart health.

Types of Fiber

Although there are several forms of fiber, they can be classified into two major groups: soluble fiber and insoluble fiber. While both are good for the body, only one group has been shown to be beneficial in lowering your cholesterol.

Soluble fiber can be dissolved in water and forms a gel-like consistency in the digestive tract. On the other hand, insoluble fiber cannot be dissolved in water, so it passes through the digestive tract relatively unchanged. When it comes to your heart health, it appears that only soluble fiber is beneficial in lowering your cholesterol. In fact, studies have shown that consuming 10 to 25 grams soluble fiber a day can lower cholesterol by 18%.

However, it appears to only lower your “bad” cholesterol (LDL) –- your “good” cholesterol (HDL) and triglycerides are only minimally, if at all, affected by soluble fiber. Additionally, insoluble fiber does not appear to affect cholesterol levels, but it is important in maintaining a healthy colon.

Where Can I Get Soluble Fiber?

A variety of foods contain soluble fiber. By consuming the recommended amounts of fruits, vegetables, whole grains, and legumes in the Food Pyramid, you should be able to obtain the recommended amount of soluble fiber each day.

While fiber supplements can be used to fulfill this requirement, it is not recommended that you use them as substitute for eating a healthy diet. Fruits and vegetables also contain important nutrients, such as vitamins, that cannot be obtained through a fiber supplement.


Rolfes SR, Whitney E. Understanding Nutrition, 3rd ed 2005.

Poli A, Marangoni F, Paoletti R, et al. Non-pharmacological control of plasma cholesterol levels. Nutr Metab Cardiovas Dis 2008; 18:S1-S16.

Brown L, Rosner B, Willett WW, et al. Cholesterol-lowering effects of dietary fiber: a meta-analysis. Am J Clin Nutr 1999; 69:30-42.

Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (PDF), July 2004, The National Institutes of Heath: The National Heart, Lung, and Blood Institute.

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