Looking for a miracle food that helps you lose weight, feel full, lowers blood sugar and cholesterol levels, and keeps you regular? Fiber is the answer. Most of us know very little about fiber, beyond the vague notion that it prevents constipation, yet it plays many critical roles in our body.
If your grandmother ever scolded you to eat more “roughage,” she was referring to the old term for fiber. So what is fiber? Fiber comes from the indigestible parts of the plants we eat, and scientists generally describe two types: soluble and insoluble. Foods that contain fiber usually contain both kinds, but in varying ratios.
“Roughage” more accurately describes insoluble fiber, which adds bulk to stools, thereby easing constipation and reducing the risk of diverticulosis (the formation of small pockets in the colon). Insoluble fiber speeds the movement of food through the small intestine, which encourages regularity. All legumes (beans, lentils, split peas, etc.), whole grains, wheat and corn bran, nuts, and seeds are particularly good sources of insoluble fiber, as well as avocados and dried fruits like apricots, figs, and prunes.
Soluble fiber is undigested in the small intestine, but absorbs water and forms a “gel.” Beneficial symbiotic bacteria in the large colon ferment the “gel” and produce short-chain fatty acids, Vitamin K, and, well, gas. (Yes, this is the gas that beans, broccoli, and other soluble-fiber rich foods can cause). The short-chain fatty acids absorbed by the large intestine are critical to maintaining the colon cell health, as well as many additional health benefits, including:
- Reducing cholesterol production by the liver, thereby reducing LDL or “bad” cholesterol and triglycerides levels and reducing the risk of atherosclerosis and coronary heart disease.
- Stabilizing blood sugar levels, thus reducing the risk of, and assisting in the treatment of, diabetes.
- Stimulating the production of cells and substances critical to the immune system.
- Making the colon acidic, which helps protect against colonic polyps, which in turn can become cancerous.
- Colonic acidity also assists in the body’s absorption of calcium and other dietary minerals.
- Inhibiting the effects of irritants and inflammation on the colon’s inner lining, thus maintaining a healthy colon.
Soluble, fermentable fiber is often called “prebiotic,” because it encourages the growth of the beneficial bacteria responsible for the above benefits.
What to eat? Fall is here, so how about split pea soup or a lentil stew? The richest common food sources of soluble fiber are legumes, including beans, lentils, and peas, and unrefined oats, including steel-cut. Rye and barley are also rich in soluble fiber, as are dried fruits. Among fresh fruits, plums, berries, bananas, apples, and pears are good sources of fiber. Pears and apples are in harvest right now. Eat at least one each day. Jerusalem artichokes (unrelated to regular artichokes) are a root vegetable that is particularly high in soluble fiber. Potatoes, both sweet and regular, and onions have lesser amounts. Globe artichokes are also very good sources, with other vegetables like carrots and broccoli having significant, but lesser amounts. Psyllium seed husks are a rich source and used in supplements, but lack the other important nutrients only a varied diet can provide. In other words, eating refined foods and compensating by taking supplemental psyllium is not the best approach.
Most Americans consume less than 50% of the recommended dietary intake of fiber. For men 19 to 50 years of age the recommendation is 38 grams total fiber, and 25 grams for women in the same age group. Older adults generally require less because their total caloric intake drops, so the corresponding recommendation is 30 grams for men and 20 grams for women. Because of their low fiber intake, many Americans are more vulnerable to digestive disorders, diabetes, and heart disease. The chart below gives you some examples of fiber in various foods. For more complete information on fiber content of individual foods, visit the World’s Healthiest Foods. Remember, although most nutrition labels list total fiber, all foods with fiber will include both soluble and insoluble fiber.
|Food Source (one cup each unless marked otherwise)||Total Fiber in Grams|
|Beans||12.1 – 19.1|
|Long-grained brown rice||3.5|
|Apple (one apple with skin)||3.7|
|Banana (one peeled banana)||2.8|
|Almonds (1/4 cup)||4.1|
|Whole wheat bread (slice)||1.9 – 3.0|
|Steel-cut oats (1/4 cup dry)||3.0|
Total fiber intake also reduces appetite and contributes to weight loss. Fiber both makes the eater feel satiated more quickly, and prolongs that feeling of fullness. The high levels of obesity found in America today, and the increasing levels found in other developed countries, is partially linked to the low fiber content in modern diets based on processed foods. Diets that consist of primarily processed foods generally contain only about 20% of the recommended intake levels for total fiber.
We don’t have to bear any hardship to add more fiber to our diets. Delicious menus for fiber-rich meals are not hard to imagine. Try this recipe generator from World’s Healthiest Foods. How about oatmeal with fresh blueberries for breakfast, followed by a lunch salad of leafy greens topped with marinated artichoke hearts, chickpeas, and crunchy pecans? After a fresh apple for a snack, dinner could be spicy chili or a rich minestrone soup, served with crusty, whole-wheat bread. Hungry, anyone?
- Rebecca Taggart