July 28, 2009

Health Benefits of Fiber

Why is fiber the favored component of dietitian-recommended meal plans? Because increasing dietary fiber provides a number of healthful benefits for the body. The American Dietetic Association’s position on the Health Implications of Dietary Fiber outlines the benefits of fiber in four key areas:

• Cardiovascular disease prevention
• Gastrointestinal health
• Weight management
• Diabetes

Heart Health

Increasing dietary fiber helps lower total cholesterol levels and LDL (“bad cholesterol”). Blood cholesterol levels are reduced when bile acids are excreted from the body. Soluble fiber binds bile acids. This may help explain why increasing dietary fiber – particularly the soluble type - increases excretion of cholesterol, which in turn lowers levels of cholesterol circulating in the blood.

Gut Check

Insoluble fiber binds water, making your stools softer, bulkier and heavier. This helps move things along in the gut, reducing the likelihood of constipation, hemorrhoids and diverticulosis.

Weight Loss

High fiber foods like fruits, vegetables, whole grains and legumes such as kidney beans and lentils increase satiety. Satiety is the feeling of fullness. High fiber fruits and vegetables tend to be low in calories, which help satisfy and counteract hunger with relatively few calories. Foods that are high in fiber make you feel fuller for longer and decrease consumption of excessive calories that lead to weight gain.

Blood Sugar Regulation

Fiber containing foods take longer to digest than their lower-fiber counterparts. Certain types of fiber slow gastric emptying and glucose absorption. For people with diabetes, including high fiber foods is beneficial for normalizing blood sugar levels1.

What About Cancer?

Contrary to popular belief, there is not a clearly established link between dietary fiber intake and the development of colon cancer. Increasing dietary fiber intake may be associated with lower rates of colon cancer, but the exact mechanism of the relationship is not entirely known. Diets high in animal fats and protein – which tend to be low in fiber – have been linked to higher rates of colon cancer2.

One thing to keep in mind is that you don’t increase your risk of any chronic disease by increasing dietary fiber. Even though we may not know exactly why fiber is beneficial in every disease state, it seems safe to say that increasing dietary fiber is almost always helpful and rarely harmful.

1. Jenkins DJ, Kendall CW, Augustin LS,Vuksan V. High-complex carbohydrate or lente carbohydrate foods? Am J Med. 2002;113(suppl 9B):30S-37S
2. Lanza E, Yu B, Murphy G, Albert PS, Caan B, Marshall JR, Lance P, Paskett ED, Weissfeld J, Slattery M, Burt R, Iber F, Shike M, Kikendall JW, Brewer BK, Schatzkin A. Polyp Prevention Trial Study Group. The polyp prevention trial continued follow-up study: No effect of a low-fat, high-fiber, high-fruit, and vegetable diet on adenoma recurrence eight years after randomization. Cancer Epidemiol Biomarkers Prev. 2007;16:1745-1752