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Roughing It - Fiber!

Introduction

Fiber is one of those nutrients that many of us know is important but that remains a bit of a mystery. Exactly what is it? What are the best sources of fiber? What are its health benefits? Let’s try to find some answers!

The term fiber refers to carbohydrates that cannot be digested. Fiber is present in all plants that are eaten for food, including fruits, vegetables, grains and legumes. One way of categorising fiber is by how easily it dissolves in water. Soluble fiber partially dissolves in water. Insoluble fiber does not dissolve in water.

Health Effects of Eating Fiber

Long heralded as part of a healthy diet, fiber appears to reduce the risk of developing various conditions, including heart disease, diabetes, diverticular disease and constipation.

Fiber and Heart Disease

Coronary heart disease is a leading cause of death for both men and women. This disease is characterized by a buildup of cholesterol in the arteries that feed the heart. Total blockage of a coronary artery produces a heart attack.

High intake of dietary fiber has been linked to a lower risk of heart disease in a number of large studies that followed people for many years. Several studies suggest that higher intake of fiber may somehow also reduce the risk of metabolic syndrome.

Fiber and Type 2 Diabetes

Type 2 diabetes is characterized by sustained high blood sugar levels. It tends to develop when the body can no longer produce enough of the hormone insulin to lower blood sugar to normal levels or cannot properly use the insulin that it does produce.

There are several important factors that may help lower your risk for type 2 diabetes, such as maintaining a healthy weight, being physically active and not smoking. Now we also know that a diet high in fiber is linked to a lower risk of type 2 diabetes.

Fiber and Diverticular Disease

Diverticulitis, an inflammation of the intestine, is one of the most common age-related disorders of the colon in Western society. Eating dietary fiber, particularly insoluble fiber, is associated with about a 40 percent lower risk of diverticular disease.

Fiber and Constipation

Constipation is the most common gastrointestinal complaint in the Western society. The good news is that the gastrointestinal tract is highly sensitive to dietary fiber and consumption of fiber seems to relieve and prevent constipation.

Experts recommend increasing fiber intake gradually rather than suddenly. As fiber intake is increased, the intake of beverages should also be increased, since fiber absorbs water. 

The Bottom Line: Recommendations for Fiber

  • Current recommendations:

Age (years)

 

Fiber intake (grams) 

Children

 

  1-3 

 19

  4-8 

 25

Boys and Men

 

  9-13 

 31

  14-18 

 38

  19-30 

 38

  31-50 

 38

  51-70 

 30

  70+ 

 30

Girls and Women

 

  9-13 

 26

  14-18

 26

  19-30 

 25

  31-50 

 25

  51-70

 21

  70+ 

 21  

Source: Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. 2002. Washington, D.C.: The National Academies Press.

Fiber Sources

Soluble Fiber

  • Oatmeal, oatbran
  • Nuts and seeds
  • Legumes
  • Beans
  • Dried peas
  • Lentils
  • Apples
  • Pears
  • Strawberries
  • Blueberries

 Insoluble Fiber

  • Whole wheat bread
  • Barley
  • Couscous
  • Brown rice
  • Bulgur
  • Whole grain breakfast cereals
  • Wheat bran
  • Seeds
  • Carrots
  • Cucumbers
  • Zucchini
  • Celery
  • Tomatoes

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