Dietary fiber — found mainly in fruits, vegetables, whole grains
and legumes — is probably best known for its ability to prevent or
relieve constipation. But foods containing fiber can provide other
health benefits as well, such as helping to maintain a healthy
weight and lowering your risk of diabetes and heart disease.
Dietary fiber, also known as roughage or bulk, includes the
parts of plant foods your body can't digest or absorb. Unlike other
food components, such as fats, proteins or carbohydrates — which
your body breaks down and absorbs — fiber isn't digested by your
body. Instead, it passes relatively intact through your stomach,
small intestine and colon and out of your body.
Fiber is commonly classified as soluble, which dissolves in
water, or insoluble, which doesn't dissolve.
- Soluble fiber. This type of fiber dissolves in
water to form a gel-like material. It can help lower blood
cholesterol and glucose levels. Soluble fiber is found in oats,
peas, beans, apples, citrus fruits, carrots, barley and
psyllium.
- Insoluble fiber. This type of fiber promotes
the movement of material through your digestive system and
increases stool bulk, so it can be of benefit to those who struggle
with constipation or irregular stools. Whole-wheat flour, wheat
bran, nuts, beans and vegetables, such as cauliflower, green beans
and potatoes, are good sources of insoluble fiber.
Most plant-based foods, such as oatmeal and beans, contain both
soluble and insoluble fiber. However, the amount of each type
varies in different plant foods. To receive the greatest health
benefit, eat a wide variety of high-fiber foods.
Benefits of a high-fiber diet
A high-fiber diet has many benefits, which include:
- Normalizes bowel movements. Dietary fiber
increases the weight and size of your stool and softens it. A bulky
stool is easier to pass, decreasing your chance of constipation. If
you have loose, watery stools, fiber may help to solidify the stool
because it absorbs water and adds bulk to stool.
- Helps maintain bowel health.A high-fiber diet
may lower your risk of developing hemorrhoids and small pouches in
your colon (diverticular disease). Some fiber is fermented in the
colon. Researchers are looking at how this may play a role in
preventing diseases of the colon.
- Lowers cholesterol levels.Soluble fiber found
in beans, oats, flaxseed and oat bran may help lower total blood
cholesterol levels by lowering low-density lipoprotein, or "bad,"
cholesterol levels. Studies also have shown that high-fiber foods
may have other heart-health benefits, such as reducing blood
pressure and inflammation.
- Helps control blood sugar levels. In people
with diabetes, fiber — particularly soluble fiber — can slow the
absorption of sugar and help improve blood sugar levels. A healthy
diet that includes insoluble fiber may also reduce the risk of
developing type 2 diabetes.
- Aids in achieving healthy weight. High-fiber
foods tend to be more filling than low-fiber foods, so you're
likely to eat less and stay satisfied longer. And high-fiber foods
tend to take longer to eat and to be less "energy dense," which
means they have fewer calories for the same volume of food.
- So it has been linked to maintain normal weight and prevents
the risk of obesity and it's consequences such as Diabetes and
heart diseases. (Diet with whole grain foods, vegetables, fruits
provide sufficient amount of fiber to maintain normal body weight
apart from physical exercises).
- for weight management and obesity:: use dietary fibres to
prolong satiety. This was logical, as some types of fibre absorb a
lot of after, thereby literally filling the stomach without
providing a lot of calories. Fibres are also an energy source for
various intestinal bacteria, and the intestine, too, provides
signals to the brains on the extent to which energy requirements
are met.
Another benefit attributed to dietary fiber is prevention of
colorectal cancer. However, the evidence that fiber reduces
colorectal cancer is mixed.