Bulking Up on Fiber
Fiber: you know you need to eat it. You are pretty sure it is good for you. And according to reports, you, like many other Americans, aren't getting anywhere as much fiber as you should. But what is fiber, really ? And why is it good for you?
What Are the Facts?
Fiber is found only in plants. It is from the plant cells, particularly the cell walls. The plant fiber that we eat is called dietary fiber. It is unique from other components of the plant because humans lack the enzymes necessary to digest it.
Dietary fiber is made up of two types of fiber: soluble and insoluble. Soluble means that when the fiber is mixed with a liquid, it forms a gel-like solution. Insoluble fiber does not mix with liquid and passes through the digestive tract largely intact. Both types of fiber help maintain bowel regularity.
Soluble fiber
Soluble fiber has been found to provide some additional health benefits. When eaten as part of a low-fat, low-cholesterol diet, soluble fiber can help lower cholesterol. Weaker and somewhat inconsistent evidence hints at a link between soluble fiber intake and a reduced risk of certain cancers, diabetes, digestive disorders, and heart disease. Examples of foods high in soluble fiber include pears, Brussels sprouts, lima beans, Northern beans, and psyllium.
Insoluble fiber
Although insoluble fiber has not been shown to lower cholesterol, it is important for normal digestive health. Insoluble fiber speeds up movement through the small intestine and helps to alleviate constipation . Foods that are high in insoluble fiber include apples, beans (eg, black beans, navy beans, pinto beans), lentils, All Bran cereal, wheat germ, and brown rice. With both soluble and insoluble fiber, flaxseed is one food that is being studied for its ability to lower cholesterol and decrease constipation. Researchers are also investigating whether these seeds have anti-cancer properties. Just one tablespoon of ground flaxseed provides 2.2 grams of total fiber, as well as 1.8 grams of alpha-linolenic acid, a type of omega-3 fatty acid .
How Much Fiber Do I Need?
Health experts recommend eating a minimum of 20-30 grams of fiber daily. This includes both soluble and insoluble fiber. Most Americans eat about 11-15 grams a day—about half of what is recommended. The following table lists how much fiber you can find in some common foods.
Food | Serving size |
Total Fiber
(grams) | Soluble Fiber | Insoluble Fiber |
---|---|---|---|---|
Vegetables | ||||
Broccoli, cooked | ½ cup | 1.5 | 1 | 0.5 |
Brussels sprouts, cooked | ½ cup | 4.5 | 3.0 | 1.5 |
Carrots, cooked | ½ cup | 2.5 | 1 | 1.4 |
Artichoke, fresh | ½ cup | 4 | 3 | 1 |
Fruits | ||||
Apple | 1 medium | 4 | 1 | 3 |
Banana | 1 medium | 3 | 1 | 2 |
Blackberries | ½ cup | 4 | 1 | 3 |
Nectarine | 1 medium | 2 | 1 | 1 |
Citrus fruit (orange, grapefruit) | 1 medium | 2-3 | 1 | 1-2 |
Peach | 1 medium | 2 | 1 | 1 |
Pears | 1 medium | 4 | 2 | 2 |
Plums | 1 medium | 1.5 | 1 | 0.5 |
Prunes | ¼ cup | 3 | 1.5 | 1.5 |
Legumes | ||||
Black beans, cooked | ½ cup | 5.5 | 2 | 3.5 |
Kidney beans, cooked | ½ cup | 6 | 3 | 3 |
Lima beans, cooked | ½ cup | 6.5 | 3.5 | 3 |
Navy beans, cooked | ½ cup | 6 | 2 | 4 |
Northern beans, cooked | ½ cup | 5.5 | 5 | 0.5 |
Pinto beans, cooked | ½ cup | 7 | 2 | 5 |
Lentils, cooked | ½ cup | 8 | 1 | 7 |
Peas, cooked | ½ cup | 6 | 1 | 5 |
Whole grain cereals | ||||
All Bran cereal | 1/3 cup | 8 | 0.7 | 7.3 |
Oatmeal, cooked | ½ cup | 2 | 1 | 1 |
Oat bran | ½ cup | 3 | 2 | 1 |
Shredded wheat | 2/3 cup | 3 | 0.3 | 2.7 |
Wheat germ | 2/3 cup | 8 | 1 | 7 |
Pearl barley, cooked | ½ cup | 5 | 2 | 3 |
Brown rice | ½ cup | 4 | 0.5 | 3.5 |
Seeds | ||||
Psyllium seeds | 1 tablespoon | 6 | 5 | 1 |
Source: Journal of Family Practice
How Do I Increase the Amount of Fiber in My Diet?
It is easy to increase the fiber in your diet—it just takes a little thought and some action. Here are a few ideas to help you get on track to 30 grams of fiber a day.
- Try a whole grain cereal that contains at least 5 grams of fiber per serving. Slice a banana on top, or add some raisins or berries to increase the fiber even more.
- Sprinkle a few teaspoons of wheat germ, ground psyllium, or ground flaxseed on your food.
- Try eating some vegetables raw. Cooking can break down some of the fiber content. If you do cook vegetables, steam them lightly, so they are tender but still firm.
- Leave the skin on fruits and vegetables. Just make sure you rinse them well with warm water to remove any dirt or bacteria.
- Eat the whole fruit or vegetable instead of drinking the juice made from it. Juice does not contain the skin or membrane of the fruit or vegetable, and therefore its fiber content is substantially reduced.
- Try adding whole, unprocessed grain to your diet. Substitute brown rice for white rice. Or opt for whole wheat bread or pasta.
- Add beans to your soups, salads, and stews. Throw some beans on top of a salad or add lentils to soup while cooking.
- Snack on fresh and dried fruit. Chomp some raisins or dried apricots in the afternoon, instead of a bag of potato chips or pretzels.
A Word of Caution…
When you begin to increase the fiber in your diet, take it slow. Increasing too quickly can upset your intestinal tract and you may experience gas, bloating, cramps, or even constipation or diarrhea . By increasing your fiber intake just a few grams a day, your intestinal tract will have time to adjust. Other tips to help minimize upset include:
- Drink at least eight 8-ounce cups of water a day.
- Use enzyme products, such as Beano, to help you digest fiber.
- Do not cook dried beans in the same water in which you soaked them.
Click here for fabulous fiber recipes .
RESOURCES:
American Dietetic Association
http://www.eatright.org/
My Pyramid—United States Department of Agriculture
http://www.mypyramid.gov/
CANADIAN RESOURCES:
Canadian Council on Food and Nutrition
http://www.ccfn.ca/
Dietitians of Canada
http://www.dietitians.ca/
References:
American Dietetic Association website. Available at: http://www.eatright.org/ . Accessed February 19, 2009.
Fiber. American Heart Association website. Available at: http://www.americanheart.org/presenter.jhtml?identifier=4574 . Accessed February 19, 2009.
Flax—a healthy food. Flax Council of Canada website. Available at: http://www.flaxcouncil.ca/english/index.jsp?p=g1mp=nutrition. Accessed April 21, 2010.
Flaxseed. EBSCO Natural and Alternative Treatments website. Available at: http://www.ebscohost.com/thisTopic.php?marketID=15topicID=114. Updated February 2010. Accessed April 21, 2010.
Shamliyan T, Jacobs D, Raatz S, Nordstrom D, Keenan J. Are your patients with risk of CVD getting the viscous soluble fiber they need? Journal of Family Practice. 2006;9:761-769. EBSCO Consumer Health Complete website. Available at: http://www.ebscohost.com/thisMarket.php?marketID=14. Published September 2006. Accessed April 20, 2010.
Last reviewed February 2009 by Maria Adams, MS, MPH, RD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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