The term dietary fibers refers collectively to indigestible carbohydrates present in plant foods. The importance of these dietary fibers came into the picture when it was observed that the people having diet rich in these fibers, had low incidence of coronary heart disease, irritable bowel syndrome, dental caries and gall stones.
The foodstuffs rich in these dietary fibers are cereals and grains, legumes, fruits with seeds, citrus fruits, carrots, cabbage, green vegetables with leanes, apples, melons, peaches, pears, etc.
These dietary fibers are not digested by the enzymes of the stomach and the small intestine whereas, most of the other carbohydrates like starch and sugar are digested and absorbed. The dietary fibers have the property of holding water and because of it, they get swollen and behave like a sponge as these pass through the gastrointestinal tract. The fibers add bulk to the diet and increase transit time in the gut. Some of these fibers may undergo fermentation in the colon.
In recent years, it has been considered essential to have some amount of fibers in the diet. Their beneficial effects help in preventing coronary heart disease, and decreasing cholesterol levels. The fibers like gums and pectin are reported to decrease postprandial (after meals) glucose level in blood. These types of dietary fibers are recommended for the management of certain types of diabetes. Recent studies have shown that the fenugreek (Methi) seeds, which contain 40 percent gum, are effective in decreasing blood glucose and cholesterol levels as compared to other gum containing vegetables.
Some dietary fibers increase transit time and decrease the time of release of ingested food in colon. The diet having less fibers is associated with colon cancer and the dietary fibers may play a role in decreasing the risk of it.
The dietary fibers hold water so that stools are soft, bulky and readily eliminated. Therefore, high fiber intake prevents or relieves constipation. The fibers increase motility of the small intestine and the colon and by decreasing the transit time there is less time for exposure of the mucosa to harmful toxic substances. Therefore, there is less desire to eat and the energy intake can be maintained within the range of requirement. This phenomenon helps in keeping a check on obesity. Another reason in helping to decrease obesity is that the high-fiber diets have somewhat lower coefficients of digestibility.
The dietary fibers may have some adverse effects on nutrition by binding some trace metals like calcium, magnesium, phosphorus, zinc and others and therefore preventing their proper absorption. This may pose a possibility of nutritional deficiency especially when diets contain marginal levels of mineral elements. This may become an important constraint on increasing dietary fibers. It is suggested that an intake of 40 grams dietary fibers per day is desirable.
Q. On the basis of your reading of the above passage, make notes in points only, using abbreviations wherever necessary. Provide a suitable title.
Title: Dietary Fibers
- Importance: lowers
- hrt disease
- irrtble bowel syndrome
- dental caries
- gall stones
- Rich dietary fibers
- cereals, grains, legumes
- Adverse effects
- bind metals like ca, mg, ph, zn
- prevents their absoptn
- nutnl defcncy
- Hrt. – heart
- Irrtble. – irritable
- Ca. – calcium
- Mg. – magnesium
- Ph. – phosphorous
- Zn. – zinc
- Absoptn. – absorption
- Nutnl. – nutritional
- Defcncy. – deficiency
Q. Write a summary of the above in about 80 words.
Dietary fibers are indigestible carbohydrates present in plant foods. People having diet rich in fibers have low heart diseases, irritable bowel syndrome, dental caries and gall stones. Sources of dietary fibers are legumes, cereals, fruits, vegetables and grains. The fibers like gums present in fenugreek and pectin decrease glucose level. The diet which is less in fibers results in colon cancer. The dietary fibers hold water and functions like sponge, hence they prevent constipation. But there are adverse effects also. They bind some trace metals resulting in nutritional deficiency.