Anthony, newly diagnosed with diabetes, did not know what to buy at the grocery store. “It’s all so confusing,” he said. “My dietitian told me I needed to eat more fiber, but these days, even Fruit Loops is advertising its fiber content. Does that mean it’s good for me?”
Like Anthony, anyone who has shopped at a mainstream grocery store lately has probably noticed a lot of new products touting their fiber or whole-grain content. In the bread aisle, there’s whole-grain white bread, bagels, and English muffins, as well as whole wheat bread with double the fiber. In the cereal aisle, products such as Froot Loops that used to sell themselves on the basis of taste, texture, or special added ingredients now call attention to their supposed health benefits because of added fiber. And in the dairy aisle, some formerly fiber-free products such as yogurt and cottage cheese now have 3 grams of fiber per serving.
It is no wonder that Anthony — and many others — are confused. How is it possible for white flour to be whole wheat? Does the addition of fiber make a sugary cereal a health food? And does the fiber being added to dairy products and other foods have the same benefits as the fiber found naturally in fruits, vegetables, and whole grains?
Study after study has proven that a diet high in fiber has favorable effects on blood glucose, cholesterol, triglycerides, blood pressure, and weight management. The American Diabetes Association advises people with diabetes to consume a variety of fiber-containing foods and to set a fiber intake goal of at least 14 grams of fiber for every 1,000 calories.
Dietary fiber is the edible part of plants that is resistant to digestion and absorption in the small intestine. Fiber is probably best known for preventing constipation, but it is also recommended for the prevention and treatment of diverticulosis (the development of small pouches in the colon that can become inflamed) and for prevention of heart disease. Fiber helps with weight control by providing a feeling of fullness in the stomach after eating.
Fiber comes in two main forms, commonly referred to as soluble and insoluble; soluble fibers dissolve in water, while insoluble fibers do not. However, some nutrition experts have started to categorize the various types of fiber by different names that better describe their effects in the body. For example, the term “viscous fiber” refers to soluble fibers that form a gummy gel during digestion. This gel slows the rate at which food leaves the stomach, helping to lower blood glucose levels after meals. Viscous fiber has also been shown to increase insulin sensitivity. And a diet high in viscous fiber can help to lower low-density lipoprotein (LDL, or “bad”) blood cholesterol levels. Good food sources of viscous fiber include oat bran, barley, nuts, seeds, beans, citrus fruits, apples, and pears.
Another term used for certain types of soluble fiber is “fermentable fiber,” because it partially or completely ferments in the large intestine. The fermented fibers are broken down into short-chain fatty acids that help to maintain the health of the colon. Food sources of fermentable fibers include oats, barley, fruits, and vegetables. (Some soluble fibers are both viscous and fermentable.)
Insoluble fiber helps to speed the passage of food through the digestive system and adds bulk to stool. Good food sources of insoluble fiber include wheat bran, legumes, vegetables, and whole grains.
In spite of the established benefits of fiber, many Americans don’t consume all that much. In fact, the average American consumes only a total of 14 grams of fiber a day, rather than the recommended 14 grams per 1,000 calories. Reasons for low fiber intake no doubt vary, but many people don’t like the taste or texture of high-fiber foods, or they feel that preparing such foods is too difficult or too time-consuming.