Insights by Goldie: Fiber and the heart-health connection

by Goldie Caughlan

This article was originally published in February 2003

The American Heart Association (AHA) says there is “overwhelming evidence that dietary factors influence risk of coronary heart disease, both favorably and unfavorably, and that the three most atherogenic* dietary risk factors are saturated fat, cholesterol and obesity.”

It recommends addressing these serious risk factors through AHA approved diets with “increased carbohydrate intake, especially complex carbohydrates … [aimed at] reducing intake of total fat, saturated fat, and cholesterol.” It states that “choosing fiber-rich carbohydrate sources may foster additional cholesterol lowering and other nutritional benefits beyond those derived from fat modification alone.”

AHA recommends that adults should have 25-30 grams of dietary fiber a day — recommending that they be “from food, not from supplements.” Estimated current fiber intake is 15 grams or less. Unfortunately, the USDA Food Pyramid lists no target numbers or guidance as to types, amounts, or sources of fiber. But the foundation level of the Food Pyramid recommends six to 11 grain servings daily and the second level lists five to nine servings of fruits and vegetables. All dry beans, legumes, lentils, seeds and nuts, mentioned as protein alternatives to meat, fish or poultry, are included on the third level of the Food Pyramid and are also very high in fiber.

Fiber: types and sources

Remember this important fact: Fiber is found only in plants, mostly in the walls of their cells. Types include cellulose, hemicellulose, pectin and lignin. All food fiber plays an important health role in combination with low-fat, complex carbohydrate-centered (also called “plant centered”) meals.

Plant centered does not necessarily mean eating a vegetarian diet, although the AHA states that vegetarians generally have the lowest levels of blood cholesterol — especially vegan vegetarians, who include no animal foods or saturated animal fats. A vegetarian diet can be very heart healthy, if based on a wide variety of whole foods. Plant centered eating means a food pattern consciously grounded in many daily servings of grains, beans, legumes, vegetables and fruits, and some nuts and seeds. Then fish, low-fat dairy, poultry and meat also can have a place in a plant centered meal.

Two categories of fiber

Soluble fiber mixes with liquids to form a kind of gel and is mostly digested. This is the predominate form of fiber found in certain fruits such as apples, pears, and many berries, and in dry beans, peas, legumes, and oats, barley, and brown rice, as well as flax and psyllium seed. Some forms of soluble fiber, especially oat fiber (rich in a substance called beta glucan) is recognized as beneficial for helping to reduce the harmful portion of blood cholesterol and thus help reduce risk of heard disease and stroke (when combined with otherwise heart-healthy diets). Currently, only the beta glucan found in oat fiber can be included with health claims on product labels. Most health advisors believe similar benefits are associated with the other food sources of soluble fiber.

Insoluble fiber (called “roughage”) is found abundantly in the outer layer of wheat (wheat bran), rye, in some nuts, and some other grains. It provides bulk, is not digested, and provides a sensation of satiety (a pleasant feeling of fullness but not “stuffed”). Insoluble fiber holds liquid, helps prevent constipation and more comfortable elimination without straining.

Grains are good sources of fiber only if unrefined — not stripped of their bran as in the case of white rice, white flour, refined cereals, refined semolina pasta, enriched white breads, white crackers, and most pastries.

Fruits and vegetables are good sources of fiber, whether eaten raw, dried or cooked, but not if juiced. Juice is rich in vitamins and minerals — but juicing removes all or most all fiber. Think: “whole” fruits and vegetables. That means not peeling or overly scraping your veggies and fruits. Okay, okay, you can peel the banana and orange … but remember to eat those baked, roasted or boiled spuds, beets, parsnips, rutabagas, turnips or other roots, as well as sweet potatoes, yams and squash — skins and all! Crunch a carrot. Eat scads of dark greens. Have a few nuts such as almonds or sunflower seeds every day. Plan on some form of cooked dry bean or lentils everyday, in salad, soup or a dip. Grab an apple instead of ice cream. Pop some corn and skip the butter. And read those bread labels: if the first or second ingredient does not say “whole-grain flour” choose another brand or type.

Dropping our guard on this mindful approach to food choices is partly what leads to the sad state of health evidenced at any drugstore with its rows upon rows of fiber supplements, antacids and laxatives, not to mention the many related medications which, in part, are related to dietary choices. Billions of bucks are spent annually on such over-the-counter fixes. Rather than seeking a “fix” after the fact, perhaps we need to “fix” the concepts of “increased fiber” and “decreased fats/especially saturates” in our mind as a good food guide.

Remember, too: If you are consciously just beginning to increase more fiber-rich foods in your diet, be certain you’re taking in plenty of liquids — eight to 10 glasses a day, including cooking liquids and beverages. Also, be aware that you can experience some gassy discomfort at first if yours has been a diet very lacking in fiber, as your system adjusts and learns to accommodate to higher fiber foods — but it’s well worth the effort.

Finally, if you’re looking up fiber content of foods in reference books, be sure your source was developed after about 1980, so it specifies “Dietary Fiber” rather than “Crude Fiber” as is given in older sources.

*atherogenic means contributing to a deposit or degenerative accumulation of pulpy, acellular, lipid-containing materials, especially in arterial walls.

Selected sources and amounts of dietary fiber

Food Amount Soluble Fiber, g Total Fiber, g
Source: American Heart Association
Legumes (cooked)
Kidney beans 1/2 cup 2.0 6.7
Pinto Beans 1/2 cup 2.0 6.7
Vegetables (cooked)
Brussels sprouts 1/2 cup 2.0 3.8
Broccoli 1/2 cup 1.1 2.6
Spinach 1/2 cup 0.5 2.1
Zucchini 1/2 cup 0.2 1.6
Fruits (raw)
Apple 1 medium 1.2 3.6
Orange 1 medium 1.8 2.9
Grapefruit 1/2 medium 1.1 1.8
Grapes 1 cup 0.3 1.1
Prunes 6 medium 3.0 8.0
Oatmeal (dry) 1/3 cup 1.3 2.8
Oat bran (dry) 1/3 cup 2.0 4.4
Corn flakes 1 ounce 0.1 0.3
Brown rice (cooked) 1/2 cup 0.4 5.3
Whole-wheat bread 1 slice 0.4 2.1
White bread 1 slice 0.2 0.4

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