The Benefits of Fiber

Fiber received little respect until the 1970’s when evidence began to emerge documenting its nutritional value. Prior to these studies emerging fiber was thought of as just the roughage in plant foods, which the body could not completely digest. What was being discovered was that the populations where plant protein was high, an exceptionally low rate of chronic disease was found.

Plants consist of two main types of fiber-soluble and insoluble. Both play a role in disease prevention. Soluble fiber is gummy and found more in fruits, some vegetables, dried beans and peas, and oat products. Insoluble fiber accounts for about 70% of the fiber in our diets and is concentrated in wheat bran.

Fiber and Heart Disease: While the numbers are dropping heart disease is still the number one killer in America. The American Heart Association recommends a low-fat, low-cholesterol diet for individuals with or at risk of heart disease. However this type of diet has been shown to lower blood cholesterol levels only 5 to 7 percent. A high fiber diet, particularly high in soluble fiber, can lower cholesterol levels even farther than the AHA diet. In our research studies, low-fat, low-cholesterol diets that include up to 50 grams of fiber daily lower blood cholesterol levels 20-30 percent. For every 1 percent drop in blood cholesterol results in approximately 2% drop in risk for heart disease, this translates into about 40-60 percent reduction in heart disease risk.

Other studies have suggested that fiber may reduce risk for heart disease independent of effects on blood cholesterol. Two recent studies showed that men with the lowest cereal fiber intake had five times the rate of heart disease that men with the highest cereal fiber intake. In a study of twenty developing countries, countries with the lowest fiber intake from vegetables, fruits, grains, and legumes and the highest death rates from heart disease. In this particular study, the Unites Sates ranked lowest in fiber intake and highest in heart disease death rate.

Research also suggests that high-fiber diets lower blood pressure, but the independent effects of fiber are hard to differentiate from other aspects of a high fiber diet. Predominantly plant based diets are low in fat and sodium and high in potassium, magnesium, and calcium, all of which may contribute to lower blood pressure.

The National Cancer Institute is an advocate of high fiber diets, recommending 20-30 grams daily. Many deaths from cancer could be prevented with diet and lifestyle modification, prompting the Institute to implement the "Five a Day for Better Health" campaign which encourages five servings of fruits and vegetables daily.

Fiber can help control diabetes, a disease which is characterized by the body’s inability to produce or to use insulin properly. Insulin enables the body to use sugar as fuel for cells and when insulin is not working blood sugar levels become dangerously elevated. Diabetes itself is a risk factor for other conditions such as heart disease and high blood pressure, while obesity often precedes diabetes.

High-fiber diets improve diabetic control and may produce a remission of Type II diabetes. High fiber diets, especially those rich is soluble fiber, lower blood lipid levels, reducing risk for heart disease. High fiber diets also promote weight loss which lessens insulin insufficiency and resistance. Finally, fiber itself acts to lower blood sugar and improve insulin efficiency.

Our studies have shown that high fiber diets lowered insulin requirements of Type I diabetes an average of 38 percent. Type II diabetics on such diets have seen an average reduction of 97 percent reduction in insulin requirements. Many diabetics were able to stop insulin or oral medication entirely and still maintain healthy blood sugar levels.

High fiber diets have also been associated with lower rates of hiatal hernias, appendicitis, diverticular disease, constipation, irritable colon, bowel polyps, and hemorrhoids. Of course, the role of fiber in treating these diseases is not proven, but strong evidence supports increasing fiber intake in individuals with or at risk for these diseases.