Dietary fiber is an essential part of human nutrition as it help in many digestive and nutritional roles. Also called “roughage,” dietary fiber is a type of carbohydrate found in mostly plant based foods such as leafy greens, vegetables etc and is made up of many sugar molecules linked together. But unlike other carbohydrates (such as starch), dietary fiber is bound together in such a way that it cannot be readily digested in the small intestine.
Types of dietary fiber
There are two types of dietary fiber, and most plant foods contain some of each kind:
- Soluble fiber dissolves in water to form a thick gel-like substance in the stomach. It is broken down by bacteria in the large intestine and provides some calories.
- Insoluble fiber does not dissolve in water and passes through the gastrointestinal tract relatively intact and, therefore, is not a source of calories.
Sources of dietary fiber
Soluble fiber is found in a variety of foods, including:
- Beans and peas
- Oats (such as oat bran and oatmeal)
- Nuts and seeds
- Vegetables Insoluble fiber is found in a variety of foods, including:
- Nuts and seeds
- Wheat bran
- Whole grain foods (such as brown rice and whole grain breads, cereals, and pasta)
Benefits of dietary fiber
- Soluble fiber can interfere with the absorption of dietary fat and cholesterol.
This, in turn, can help lower low-density lipoprotein (LDL or “bad”) cholesterol levels in the blood. Soluble fiber also slows digestion and the rate at which carbohydrates and other nutrients are absorbed into the bloodstream. This can help control the level of blood glucose (often referred to as blood sugar) by preventing rapid rises in blood glucose following a meal.
- Insoluble fiber provides “bulk” for stool formation and speeds up the movement of food and waste through the digestive system, which can help prevent constipation.
- Both soluble and insoluble fiber make you feel full, which may help you eat less and stay satisfied longer.
Recommended amount of fiber
The Daily Value for fiber is 25 g per day based on a 2,000 calorie diet — your daily Value may be higher or lower depending on your calorie needs.
Lack of fiber in diet
Most Americans do not get the recommended amount of dietary fiber. Dietary fiber is considered a “nutrient of public health concern” because low intakes are associated with potential health risks.
- Diets higher in dietary fiber promote intestinal regularity and can reduce the risk of developing cardiovascular disease.