75A - Fit and Well Column for June 13th, 2004
75A - TITLE: "Fiber - For Your Health"
Dear David and Trish,
After years of fast food and generally poor nutritional habits, me and my family are finally taking responsibility for what we eat, and how we eat it. Thanks for your encouragement and challenge.
I am confused about dietary fiber. Is it really important? And should we make food choices that include this? How much? And when?
We look forward to reading your column every week. And, by the way, how is little Angelica?
Sincerely,
The Crawford Family
Dear Crawford Family,
First, Angelica is doing great… thanks for asking! We just got back from Florida, and she got to swim almost every day (she's now eight months old!). She's "tipping" the scale at thirteen pounds now, and is considering a career as a model, or possibly a movie star. We'll keep you posted!
Now… the question of fiber!
What IS Dietary Fiber?
Fiber or "roughage" is actually a catchall term for a number of non-nutritive plant substances. Chemically they are unrelated, but they all have one very unusual thing in common…they cannot be digested very well by the body. Because of this characteristic, and the fact that fiber has good water-binding capacity, or bulking properties, it is discarded quickly by the body. And, here's the GOOD news, while being discarded it carries other substances with it.
Most common sources of fiber are from the structural roots of plants - the leaves, flowers, seeds, fruits, stems and roots. The most common of these compounds is cellulose, found in the vegetable cell walls. Then there is hemicellulose, lignin and pectin, which are found in fruits. The amount of each varies from food to food, as does the total amount of fiber. One of the key questions in the fiber "controversy" is which form of fiber produces is the most effective. The jury is still out on that one.
Why is Fiber So Important?
Bran (the outer layer of the grain kernel) has been known since the 16th century to relieve constipation and promote what the advertisements call "regularity". Studies have shown that bran-eating Africans eliminate food waste in one-third the time of meat-eating Europeans. Because of this fast "transit time" and greater bulk, harmful substances presumably are also swept out before they can cause illness.
Fiber also appears to interact with intestinal bacteria and bile acids to help process certain food substances. And fiber is believed necessary to promote the wave-like contractions that keep material moving through the intestines.
Many health professionals believe that a large number of modern diseases proliferate because we have abandoned the fiber-rich diet of our ancestors.
BOX ONE:
FDA Supported Benefits of Fiber
• Diets low in fat and rich in fiber-containing grain products may reduce the risk of some types of cancer.
• Diets low in saturated fat and cholesterol and rich in fiber, particularly soluble fiber, may reduce the risk of heart disease.
• Diets low in fat and rich in fruits and vegetables, which may contain fiber or vitamin A (as beta-carotene) and vitamin C, may reduce the risk of some cancers.
• Foods with soluble fiber from whole oats may reduce heart disease risk when eaten as part of a diet low in saturated fat.
• Labels of breakfast cereal and other foods containing soluble fiber from psyllium seed husk are permitted to include claims that they may reduce the risk of coronary heart disease with a diet low in saturated fat and cholesterol.
END OF BOX ONE
Fiber … Good for What Ails You, and Preventing Disease!
Fiber is generally associated with protecting against colon cancer, with the suggestion that increasing fiber intake about an additional 13 grams per day could reduce over 30% of colorectal cancer in the U.S.
Some published evidence suggests a possible reduction in the risk of breast cancer when adequate amounts of fiber are included in the diet.
Researchers are evaluating fiber’s role relative to cancers at other sites, including the male prostate.
Dietary fiber may play several roles relative to diabetes, including potential effects on satiety, obesity and the absorption of certain sugars.
Eating whole-grain foods such as fiber-rich breakfast cereals, brown rice, barley and oatmeal may cut a person's risk of type 2 diabetes. A study of more than 4,300 adults found that those reporting the highest intake of whole grains were 35 percent less likely to develop type 2 diabetes than those with the lowest intake.
Much of this reduced risk seems to stem from the whole-grain eaters' intake of fiber-rich cereals.
Type 2 diabetes arises when the body loses its sensitivity to insulin, a hormone that shuttles sugar from the blood and into cells to be used for energy. People with the disorder see their blood sugar levels soar, which over time can lead to complications such as heart and kidney disease and nerve damage.
Fiber may combat type 2 diabetes in two ways. Compared with simple carbohydrates like white bread, fiber-rich carbs are slowly digested and absorbed, leading to less insulin demand. And insoluble fiber speeds through the intestines, leaving less time for carbohydrates to be absorbed.
Fiber could play a role in preventing cardiovascular disease owing to its effect on blood cholesterol levels, especially where initial levels are high. Some studies have found an inverse relationship between fiber and myocardial infarction (heart attack). Additionally, it may reduce blood levels of cholesterol, including LDL’s—low density lipoproteins—the "bad" cholesterol in our bloodstream.
Corn bran and hard red spring wheat bran have been proven to reduce cholesterol in humans.
Fiber can also help you eat less by providing a sense of fullness, thereby possibly helping in weight management by helping you control the quantity of food you eat.
It is also believed that soluble fiber may slow digestion and absorption of carbohydrates, possibly helping to prevent wide swings in blood sugar levels. This could also be a factor in achieving a sense of fullness, especially when you consider that fiber may hamper the absorption of calorie-dense dietary fat, too. Doesn't THAT sound great! Eat more cheeseburgers, and NOT gain weight? Well, the jury is still out on that one, too!
There are a number of modern ailments and diseases said to be associated with a low-fiber diet. These include hemorrhoids, varicose veins, hiatus hernia, appendicitis, phlebitis, intestinal polyps, gallstones and diseases of the colon. Increasing the level of fiber should assist in reducing these problems, or at least lessening their severity.
How Much Fiber is Enough?
We consume far less fiber than our grandparents did - about 4 grams a day compared to 25 grams 100 years ago. Traditional fiber diets have been discarded in favor of "meat and potatoes" and, or course, more refined foods. And this is not only fast food, but ALL typical menu items.
Talk about snatching defeat from the jaws of victory…even the old sources of fiber are transformed by modern processing methods into foods that are virtually fiber-free. For instance, we still eat plenty of wheat, but now it is in the form of white bread, pizza, pastry and some highly processed breakfast cereals whose fiber content is almost nil. And we all know that refined sugar runs rampant in our average diet.
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Fiber Rich Foods
The best vegetable sources of fiber are the leafy vegetables - asparagus, celery, broccoli, Brussels sprouts, cabbage, cauliflower and lettuce. Root vegetables like carrots, radishes and turnips also have high amounts of fiber, as do yams, beans, peas and corn. White potatoes contain fiber, although most of it is in their skins. So don't leave that on your plate! Fiber-rich fruits include those with tough skins like apples and pears; those with fibrous interiors, like peaches; and those with edible seeds like blueberries and blackberries. Nuts are a particularly good source of fiber. And they're great with Dairy Queen (which, by the way, is low in fiber, but high in smile power). BOX TWO: The Best Fiber Sources:
END OF BOX TWO Can You Eat Too Much Fiber? Very unlikely. Certain intestinal problems have been shown to be more common in fiber-eating populations. Plant fiber may tie up calcium, magnesium and zinc, preventing their absorption by the body. This should not be a problem for well-nourished individuals, however. Runners who cover over 40 miles per week lose large quantities of zinc in sweat. If they are also on a high-fiber diet, they run the risk of zinc depletion and should increase their intake of foods rich in zinc. These include oysters, red meats, wheat germ and nuts. Or, better yet, stop running, and start walking! Vegetarians should also take zinc supplements if they engage in strenuous endurance activities. Is More Fiber in YOUR Future? Although the evidence linking lack of fiber to cancer, heart disease and other afflictions is far from conclusive, most authorities agree Americans should make sensible changes in eating habits. Doubling the daily fiber intake to at least the level of 100 years ago would seem a prudent course (25 grams). You don't need to go to the extreme of adding bran to other foods. Rather, you should increase the amount of fiber from all sources. Eat whole or cracked wheat bread instead of white bread and choose whole-grain breakfast cereals rather than those that have been refined. Eat more vegetables and fresh fruits and reduce your intake of fats. Some nutritionists say that if Americans started the day with whole-grain cereal, had two vegetables with lunch and dinner and fruit for snacks and desserts, they would consume more than enough fiber to keep them healthy. So start "roughing it" in your diet, and help yourself STAY fit and well!
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