Fiber

Roughage—The Smooth Disease Fighter

If your body had a yard sale, fiber would be the junk in the bin marked "free—take it away." It's the last vestige of the food you eat, the waste that remains after your body has wrung out all the goodness it can.

But fiber is far from being an expendable part of your diet. As it passes through your system, this throwaway stuff is actually an important fighter against cancer, heart disease, and stroke. What's more, it prevents a number of other unpleasant side effects of aging.

* Fiber stops constipation.

* It alleviates diverticulosis, the formation of little pockets in the colon that can trap bacteria, bleed, and become inflamed. This malady affects more than half of all people over age 70.

* Fiber reduces hemorrhoid flare-ups.

* And a balanced diet including fiber can make your hair and fingernails look better than they have in years.

But those benefits are, well, small potatoes compared to the big-time disease prevention that you get from fiber. Researchers note that people who do nothing more than increase fiber and cut fat see cholesterol levels plummet from over 300 milligrams per deciliter (mg/dl) to under 200. That 33 percent drop in cholesterol translates into a whopping 60 percent lower risk of heart disease and stroke.

High-fiber diets also slash your risk of some forms of cancer. On its way through your body, fiber keeps cancer-causing substances from combining forces to make trouble. And it sends them toward the exit a lot faster.

Fiber doesn't travel alone. A lot of good stuff goes along for the ride. Perillyl alcohol, for instance, is concentrated in fiber. One of a group of compounds called isoprenoids, it is now being tested as an experimental treatment for people with advanced cancer.

"These compounds, isoprenoids, actually slow down the growth of tumors or stop their growth entirely," says Charles Elson, Ph.D., a researcher at the University of Wisconsin at Madison. Tumors are always trying to get started in the body, and researchers suspect that isoprenoids routinely prevent a lot of them from forming. And no one ever says thanks.

Most foods contain a combination of the two types of fiber—insoluble and soluble. Good news: Each type fights disease differently, so you get two forms of protection when you take in a mouthful of some fiber-rich foods. Wheat products and vegetables boast lots of insoluble fiber but tend to be stingy with soluble fiber. Heart-protecting soluble fiber shows up mostly in fruits, barley, oats, and beans, and these foods generally contain even more of the cancer-fighting insoluble fiber.

Now for the bad news: If you're like most older Americans, you probably get no more than 14.8 grams of fiber a day. You need 25 to 35 grams for disease protection. Luckily, you can make up the difference easily.

Keep Cancer at Bay with Insoluble Fiber

At first glance insoluble fiber doesn't seem much like a cancer fighter. It's much more like lawn mulch than food. But studies show that insoluble fiber protects you from colon cancer, and researchers believe it wards off breast, prostate, and pancreatic cancer as well.

Lots of insoluble fiber comes from the substances that form in the cell walls of plants. It's called insoluble because your body can't easily break down this type of fiber during the digestive process.

Insoluble fiber gives your stool its bulk, which helps it move more quickly through your system. That is why foods that are high in insoluble fiber—bran, for instance—are known as nature's own laxatives. In fact, one nursing home found that people who added bran cereal to their breakfasts no longer needed laxatives.

In Finland diets rich in cereals go along with low rates of breast and colon cancer. In some parts of Africa, where people eat lots of high-fiber foods, there is virtually no intestinal disease—and that includes colon cancer. In laboratory studies one component of insoluble fiber, phytic acid, actually prevents the beginning of colon cancer.

Here's how insoluble fiber works to protect you.

Dilutes the risk. Lucky you—the same stuff in insoluble fiber that keeps you from getting constipated protects you from cancer, too. Insoluble fiber soaks up water like a sponge. This makes stools bulkier. The extra bulk means that cancer-causing agents get spread out over a larger area. They can't join forces to do as much damage.

Gives a high-speed boost. On the interstate large loads move slowly. But in the intestinal highway, bulk translates into speed. Insoluble fiber gets things moving fast, so there is less time for interaction between the cells that line the colon and cancerous agents.

Creates a cancer-unfriendly environment. Fiber tinkers with the acid levels in your intestines. This changes the way bacteria do their jobs. The end result: more fermentation. While that may give you gas (okay, nothing is perfect—not even fiber), it also makes it harder for carcinogens to get into your system. Fiber also helps control levels of the intestinal bile acids that play a part in the start-up of colon cancer.

Ties up carcinogens. Substances that lead to cancer of the breast, prostate, and pancreas tend to latch onto fiber. This means that when the body says good-bye to fiber, it also waves adios to any carcinogens that have joined up.

Keeps breast cancer at bay. Insoluble fiber may reduce levels of the harmful estrogen that contributes to the beginnings of breast cancer.

In an Australian study women who ate 28 grams of fiber a day had half the breast cancer risk of women who ate less than 14 grams a day. In addition, when you eat a lot of fiber, you generally eat less fat. Researchers believe that dietary fat is a big player in postmenopausal breast cancer.

Laboratory experiments also suggest that doubling fiber intake and lowering the amount of fat you eat can drop the tumor rate by 50 percent.

Insoluble Fiber: How to Bulk Up

Insoluble is easy. If you're eating fiber-rich foods, chances are that you're getting an ample amount of the insoluble type. That's because virtually all fiber-rich foods contain more insoluble than soluble fiber. Here is how to make sure that you're getting enough.

With beans, you can do it. Hey, who needs more work? You get as much fiber benefit from canned beans as dried beans that you soak and cook yourself. Add a can of beans to vegetable and other soups, suggests Belinda Smith, R.D., research dietitian at the Veterans Affairs Medical Center in Lexington, Kentucky.

Sneak it in. Add fiber to the foods that you normally prepare. For instance, use oat bran instead of white bread as a filler in meat loaf. Add canned kidney beans to lasagna. Introduce beans into casseroles and salads, Smith suggests.

Try instant brown rice instead of instant white rice, says Alan Adelman, M.D., associate professor in the Department of Family and Community Medicine at the Milton S. Hershey Medical Center of Pennsylvania State University in Hershey.

Go whole grain. If you want refinement, take an art appreciation course. Refinement in food is another thing entirely. Refined bread, for instance, loses fiber in the milling process. So choose whole-grain bread products, which can provide 3 grams of fiber or more per slice—meaning you can get 6 grams from one sandwich.

"Refined, processed foods not only lose the fiber, but refining takes out a lot of the trace minerals and possibly the beneficial phytochemicals," notes Rosemary Newman, R.D., Ph.D., professor of food and nutrition at Montana State University in Bozeman.

Phyto-whats? She is talking about protective plant chemicals. In living plants these chemicals guard the plants from harsh weather and insects. In your body phytochemicals guard against a wide number of diseases, including heart disease, cancer, and stroke.

Read the fine print. Nutrition labels tell you the amount of fiber per serving in a food. But also look at the ingredients list. "In a bread, for instance, the first listed ingredient should be a whole grain. Better yet, the first three or four listed should be whole grains. That means there are more grains than anything else in the product," says Dr. Newman.

If you get tired of picking up and checking every loaf, concentrate on those with labels that make high-fiber claims, such as "good source of fiber."

Weigh the benefits. Not all high-fiber products are created equal. Say that you want to snack on a high-fiber granola bar. Even if the bar of your dreams has 1 or more grams of fiber, it's a good fiber deal only if the fat and calorie content are low.

"A snack bar with something like 100 calories, 2 grams of fat, and a gram of fiber is fine. But some have around 300 calories and a lot more fat. That's too much," says Dr. Newman.

Set goals. Don't try to become a fiber-gobbling machine overnight. If you think that you'll have trouble staying the course of a high-fiber diet, set small, realistic goals that you can meet, suggests Smith. Once you have accomplished those goals, set new ones. To keep yourself on track, keep a diary of what you eat.

Single out singles. Keep your fiber consumption high by lining your kitchen cabinets with easy-to-prepare, fiber-rich staples in packages that are small enough for one or two people. Even if you're an avid cook, says Smith, there will be days when you don't feel like going into the kitchen. Stock up on items such as baking potatoes, canned soup, canned beans, and cereals.

Eat with a friend. Get on the phone and flesh out your social calendar. When there are friends and family to share with, fixing a high-fiber meal seems like no effort at all, Smith notes. Other avenues for social eating: Join community groups or start your own luncheon club.

Soluble Fiber Protects the Heart

Study after study shows that soluble fiber lowers cholesterol, cutting your risk of heart disease and stroke. It may also help clear out your arteries, dropping your risk of high blood pressure.

You get soluble fiber in the outer part of some grains, the white rind in citrus fruits, and the membranes that contain each little section of grapefruit pulp. But in some plants, such as beans or barley, you find soluble fiber throughout.

One-fourth of the fiber that you take in should be soluble, says Dr. Newman. The problem is that most people don't get that much of the soluble type. A lot of foods are gold mines of insoluble fiber but contain almost no soluble materials. For example, you'll get 3 grams of fiber from 3 cups of popcorn. But a mere 0.1 gram will be soluble fiber.

In your body, soluble fiber combines with water, swelling up to create a gelatinous goo that does wonders to protect you from heart attacks and strokes. Here's how it works.

Cuts cholesterol. The higher your cholesterol levels, the greater your risk of heart disease and stroke. The soluble goo gets your cholesterol levels down. Researchers believe that once the soluble fiber reaches the small intestine, it interferes with absorption of fat. "The total amount of fat in the diet is probably the major factor in cholesterol control. In addition, soluble fiber may trap bile, which must be replaced. The replacement material is cholesterol, which is drawn out of the blood and tissues," says Dr. Newman. That cholesterol-laden bile heads on down the intestinal highway and out of the body.

But the benefits don't stop there. Elsewhere on the digestive route, bacteria break down soluble fiber to create short-chain fatty acids. When these are absorbed back into the body, they restrict the body's ability to synthesize cholesterol, reducing your blood's cholesterol levels still more.

Researchers note that some people can lower cholesterol much more cheaply and just as effectively with fiber than with cholesterol-lowering medication.

At the University of Minnesota, researchers looked at 10 studies of oat bran and found that eating just 3 grams of soluble fiber a day (what you would get in 1 cup of ready-to-eat oat bran cereal) can drop cholesterol levels by 2 to 3 percent. In people whose levels were over 230 mg/dl, cholesterol declined more steeply, an average of 6 to 7 percent. And it seems that the more oat bran people eat, the more cholesterol goes down. In one study, 6 to 9 grams of soluble fiber brought cholesterol levels of over 260 down by 23 percent.

James W. Anderson, M.D., world-renowned professor of medicine and clinical nutrition at the Veterans Affairs Medical Center, recalls that he began eating oat bran in 1977. A pioneer in oat bran research, he couldn't even get the stuff from food suppliers. Oat bran's main use in those years? Face powder.

But he found that just a bowl of cereal and three to four oat bran muffins a day lowered his cholesterol from 285 to 175 in five weeks. He also lost 8 pounds in that same time. He has been researching (and eating) oat bran ever since.

Cleans out your arteries. Researchers theorize that soluble fiber may also be an arterial housecleaner, helping to reduce the risk of the plaque buildup in your arteries that can lead to heart attacks and strokes. Soluble fiber helps lower the levels of cholesterol that circulates in your body—and that automatically drops your risk of an artery-clogging buildup.

Controls blood sugar. Soluble fiber improves the body's ability to maintain normal blood sugar, by slowing absorption of starchy foods. This helps forestall plaque buildup in the arteries, which can lead to a heart attack or stroke.

Fights high blood pressure. Researchers studied 850 Yi people, members of an ethnic minority in southwest China. They found that the Yi diet, high in oats and buckwheat, resulted in lower blood pressures and lower levels of the harmful low-density lipoprotein cholesterol.

Slashes cancer risk. In one laboratory study, researchers used a modified form of pectin, a soluble fiber. They found that this special kind of pectin helped prevent cancer from spreading. It kept cancer cells from sticking to the walls of the lungs, keeping lung tumors from getting a start.