WHAT IS DIETARY FIBER?

Dietary fiber (also known as bulk or roughage) includes all the parts of plant food that our bodies cannot digest or absorb. Dietary fiber is found only in plant foods: fruits, vegetables, nuts and grains. Meat, milk and eggs do not contain fiber.

ARE ALL DIETARY FIBERS SIMILAR?

No, there are two types of dietary fiber, soluble and insoluble. Soluble fiber dissolves in water to form a gel-like material. It is readily fermented in the colon into gases and physiologically active byproduct.

Insoluble 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. It is fiber that is metabolically inert, absorbing water throughout the digestive system and easing defecation. It acts by changing the nature of the contents of the gastrointestinal tract, and by changing how other nutrients and chemicals are absorbed.

WHAT FOODS CONTAIN FIBER?

Soluble fiber is found in oats, peas, beans, apples, citrus fruits, carrots and barley. Whole-wheat flour, wheat bran, nuts and many vegetables are good sources of insoluble fiber.

WHAT HAPPENS TO THE SOLUBLE AND INSOLUBLE FIBERS?

Insoluble fiber is not digested and is excreted. Soluble (prebiotic, viscous) fiber is readily fermented in the colon into gases and physiologically active byproduct.

WHAT ARE THE HEALTH BENEFITS OF FIBER?

Soluble fiber has been scientifically proven to lower cholesterol, which can help prevent heart disease. In addition soluble fiber: lowers total and LDL cholesterol; regulates blood sugar; balances intestinal pH and stimulates intestinal fermentation production of short-chain fatty acids; speeds the passage of foods through the digestive system; and, adds bulk to your diet, making you feel full faster

Insoluble fiber-- appears to speed the passage of foods through the stomach and intestines and adds bulk to the stool. It also facilitates regularity and alleviates constipation. (For a more detailed description see What is dietary fiber (advanced reading).

WHAT ARE SOME SIDE EFFECTS OF TOO MUCH FIBER?

Eating a large amount of fiber in a short period of time can cause intestinal gas (flatulence), bloating, and abdominal cramps. You should add fiber to your diet slowly. Increasing dietary fiber too quickly can lead to gas, bloating and cramps. This usually goes away once the natural bacteria in the digestive system get used to the increase in fiber in the diet. Adding fiber gradually to the diet, instead of all at one time, can help reduce gas or diarrhea. Too much fiber may interfere with the absorption of minerals such as iron, zinc, magnesium, and calcium. However, this effect usually does not cause too much concern because high-fiber foods are typically rich in minerals.

HOW MUCH FIBER IS NEEDED IN THE DAILY DIET?

On average, North Americans consume less than 50% of the dietary fiber levels recommended for good health. The average American now eats 10 - 15 grams of fiber per day. The recommendation for older children, adolescents, and adults is 20 - 35 grams per day.

The (American Dietary Association) ADA's recommendation for children is that intake should equal age in years plus 5 g/day (e.g., a 4 year old should consume 9 g/day).

Younger children will not be able to eat enough calories to achieve this, but it is a good idea to introduce whole grains, fresh fruits, and other high-fiber foods. To ensure that you get enough fiber, eat a variety of foods, including: cereals; dried beans and peas; fruits; vegetables and whole grains.

Add fiber gradually over a period of a few weeks to avoid abdominal discomfort. Water aids the passage of fiber through the digestive system. Drink plenty of fluids (approximately 8 glasses of water or noncaloric fluid a day). Peeling can reduce the amount of fiber in fruits and vegetables. Eating fiber-containing food is beneficial, whether it is cooked or raw.