Eat More Fiber? That Depends!
The Harvard study found that, “dietary fiber may reduce the risk of death from cardiovascular, infectious and respiratory diseases,” published in February 14′s Archives of Internal Medicine.
But, this may not mean what you think it means.
Should you be looking for foods in your supermarket that exclaim “High Fibers” in bold, bright letters? Probably not.
The term “High Fiber Diet,” when describing an eating pattern that benefits your health, is more accurately described as: “A diet high in foods which are naturally fiber-rich.”
Those who eat a diet high in foods that are naturally fiber-rich are the ones who receive the health benefits from a high fiber diet.
That is because naturally fiber-rich foods are also naturally jam-packed full of vitamins, minerals, antioxidants and other plant compounds (called “phytonutrients”), which have known health-enhancing benefits. It is the combination of nutrients, including fiber, that make people healthy—not the fiber by itself.
The National Academy of Sciences’ (NAS) Food and Nutrition Board, the group which issues periodic dietary recommendations for Americans, recommends Americans get 38 grams for men and 25 grams for women. But most Americans eat half of what is recommended, eating a highly refined diet instead. There are plenty of great reasons to increase your intake of fiber-rich foods.
Easier Weight Loss: Not eating enough fiber may be one reason why people are getting fatter.
A study published in the American Journal of Clinical Nutrition found that women with the highest fiber intake had a 49 percent lower risk of major weight gain compared with women eating less fiber.
High fiber diets are usually lower in calories. Though fiber is mainly carbohydrate, very little of it, if any, is actually digested. So, with foods high in fiber, you’re actually eating food that only partially counts as calories.
High fiber foods require more chewing and take longer to eat, which leads to more physical and psychological satisfaction with your meals.
Improved Intestinal Function: Digestive disorders are on the rise, and a main reason may be the dearth of fiber in our diets. For most digestive disorders, such as reflux disease, constipation, diarrhea, hemmorhoids, diverticulitis, ulcerative colitis, Crohn’s disease and irritable bowel syndrome, a higher fiber diet relieves symptoms and can even prevent the disorder in the first place.
Imagine fiber as a dry sponge in your intestinal tract. Fiber pulls water into the system, keeping everything larger, softer and moving more quickly and easily.
Improved Immune Function: Harvard study found a reduced risk of infectious and respiratory diseases associated with a high fiber diet. This may be because many of the foods containing nutrients instrumental in a healthy immune system happen to be high in fiber.
Lower Diabetes Risk: Numerous studies have shown that high fiber diets improve diabetes control and may even prevent diabetes.
There are several theories explaining why this may be true. First, high fiber foods tend to have a lower glycemic index. This means that after eating, blood sugar levels rise less (diabetes is characterized by high blood sugar). And studies confirm that people eating high fiber diets usually have lower fasting insulin levels, an indicator of overall lower blood sugar levels.
Also, high fiber foods contain many nutrients which may improve diabetes. For one, magnesium, a nutrient found in whole grains, legumes, tofu and some vegetables, improves insulin resistance, a cause of Diabetes Type 2, the most prevalent type of diabetes. Vitamin E, found in whole grains and nuts, may also improve insulin resistance.
Prevent Heart Disease: Fiber helps prevent heart disease in a variety of ways. Lower circulating insulin caused by a high fiber diet reduces heart disease risk and heart attacks. Also, research shows viscous fiber found in legumes, oats, rye, barley and some fruits and vegetables, reduces LDL cholesterol (the bad kind which correlates with heart attack). In fact, it has been estimated by the National Academy of Sciences’ expert panel that for every gram of soluble fiber you eat, you’ll reduce heart disease risk by 2.4 percent.
High fiber diets reduce triglycerides, or blood fat, another heart disease risk factor. New evidence shows fiber intake is linked to lower C-reactive protein, an indicator of inflammation, which is an emerging heart disease risk factor.
Whole grains and some legumes contain many beneficial healthful substances, including phytoestrogens, which affect circulating hormone levels and may impact heart disease positively. Diets high in fruits and vegetables, containing high levels of the nutrient potassium, also significantly lower blood pressure and stroke.
High fiber foods such as dark green vegetables, legumes and fortified cereals contain the nutrient, folate (or folic acid). Researchers have found that low blood levels of folate are linked to heart disease.
Reduce Cancer Risk: In populations eating low dietary fiber, doubling fiber intake from foods could reduce the risk of colorectal cancer by forty percent, according to findings in the EPIC study (European Prospective Investigation into Cancer and Nutrition), an on-going study of 500,000 people in 10 European countries.
In fact, the majority of studies suggest that dietary fiber is protective against colon cancer, according to the NAS expert panel’s report on fiber.
Several mechanisms have been proposed for this beneficial effect. First, because it pulls water into the intestinal tract, fiber dilutes carcinogens and other tumor-promoters, and causes a more rapid transit, thus causing less exposure of your body to potentially damaging substances. Fiber also causes other beneficial chemical reactions, such as lowering the ph of the colon. And lower insulin levels caused by high fiber diets are correlated with lower colon cancer risk. The EPIC researchers stressed that foods supplying fiber also contribute many other nutrients and phytonutrients (beneficial plant chemicals) that have been linked to cancer protection, according to a study in The Lancet.
But a few important studies have not found a link. Reasons given for some disappointing results connecting fiber to cancer prevention are:
The benefits of dietary fiber may not occur until fiber intake is sufficiently high. Americans eat very low levels compared with Europeans, so it’s hard for scientists to measure a positive effect in American diets.
Some studies tested fiber supplements as opposed to fiber in food, and researchers say that’s a completely different animal.
Human studies specifically looking at fiber supplements or fiber added to processed foods—such as a high fiber bran cereal—have not shown good results and did not find a lower incidence of colon polyps, a precursor to colon cancer.
Scientists believe that added fiber in processed foods or supplements will probably not produce most of the health benefits found with high fiber foods, except for improved gastrointestinal function and slightly lower LDL, if the supplement is made from viscous fibers such as guar gum or psyllium. But fiber supplements’ role in chronic disease prevention remains unproven. It is best to get fiber from whole foods in your diet.
Looking for a delicious way of eating your fiber? My book, “Diet Simple,” contains tons of recipes, tips and strategies. And try my Cranberry, Orange, Toasted Walnut Whole Grain Muffins…
Katherine Tallmadge, M.A., R.D. custom-designs nutrition, weight loss and wellness programs, is author of “Diet Simple.” For more information on the content of fiber in foods, go to KatherineTallmadge.com
Cranberry – Orange – Toasted Walnut Whole-Grain Muffin
1 1/2 cups King Arthur Traditional Whole Wheat Flour or King Arthur 100% White Whole Wheat Flour
3/4 cup quick-cooking oats (put through the food processor, depending on texture preference)
1/4 cup buttermilk powder or nonfat dry milk
2/3 cup sugar
2 teaspoons baking powder
1/4 to 1/2 teaspoon baking soda
1/2 teaspoon salt
1 cup fresh or frozen cranberries* chopped (I used fresh)
1/2 cup chopped pecans or walnuts (I toasted them)
1 tablespoon orange zest
2 large eggs
3/4 cup milk (I used buttermilk)
1/3 cup vegetable oil
2 tablespoons orange juice
3 tablespoons sugar, or 1 cup confectioners' sugar, sifted
*For a sweeter muffin, substitute 1 cup sweetened dried cranberries.
Preheat the oven to 375°F. Grease the wells of a muffin tin, or line with papers, and grease the inside of the papers.
Muffins: In a medium-sized bowl, whisk together the dry ingredients, then stir in the cranberries and nuts. Whisk together the orange zest, eggs, milk, and oil or melted butter. Add the wet ingredients to the dry ingredients, stirring until blended; don't beat, or your muffins will be tough! Fill the muffin cups or liners about 3/4 full. Bake for 18 to 20 minutes, until golden brown. Remove them from the oven, leave them in the pan for 5 minutes, then take out of the pan and transfer them to a rack to finish cooling.
Glaze: In a small saucepan or microwave-safe bowl, stir together the glaze ingredients. Bring just to a boil to dissolve the sugar. Dip the tops of the warm muffins into the glaze.