Question

Read the passage given below and answer the questions that follow: 

The term dietary fibres refers collectively to indigestible carbohydrates present in plant foods. The importance of these dietary fibres came into the picture when it was observed that the people having diet rich in these fibres, had low incidence of coronary heart disease, irritable bowel syndrome, dental caries and gall stones.

The foodstuffs rich in these dietary fibres are cereals and grains, legumes, fruits with seeds, citrus fruits, carrots, cabbage, green leafy vegetables, apples, melons, peaches, pears etc.

These dietary fibres are not digested by the enzymes of the stomach and the small intestine whereas most of other carbohydrates like starch and sugar are digested and absorbed. The dietary fibres have the property of holding water and because of it, these get swollen and behave like a sponge as these pass through the gastrointestinal tract. The fibres add bulk to the diet and increase transit time in the gut. Some of these fibres may undergo fermentation in the colon.

In recent years, it has been considered essential to have some amount of fibres in the diet. Their beneficial effects lie in preventing coronary heart disease, and decreasing cholesterol level. The fibres like gums and pectin are reported to decrease postprandial (after meals) glucose level in blood. These types of dietary fibres are recommended for the management of certain types of diabetes. Recent studies have shown that the fenugreek (Methi) seeds, which contain 40 per cent gum, are effective in decreasing blood glucose and cholesterol levels as compared to other gum containing vegetables.

Some dietary fibres increase transit time and decrease the time of release of ingested food in colon. The diet having less fibres is associated with colon cancer and the dietary fibres may play a role in decreasing the risk of it.

The dietary fibres hold water so that stools are soft, bulky and readily eliminated. Therefore high fibre intake prevents or relieves constipation.

The fibres 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 a 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-fibre diets have somewhat lower coefficients of digestibility.

The dietary fibres 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 important constraints on increasing dietary fibres. It is suggested that an intake of 40 grams dietary fibres per day is desirable.

(Extracted from ‘The Tribune’)

(a) On the basis of your reading of the above passage make notes on it in points only, using recognizable abbreviations wherever necessary. Also suggest a suitable title. (5)

(b) Write a summary of the above in about 80 words. (3)

Answer 1

(a) Title: A Fibrous Diet, a Healthy Diet!

Notes:

1. Dietary fib. & its sources

1.1 Indigestible carbs in plant foods

1.2 Cereals, grains & legumes

1.3 Fruits with seeds: citrus fruits, apples, melons

1.4. Vegetables: green & leafy, carrots, cabbages

2. Mechanism of digestion

2.1 Undigested by enzymes of stomach & small intestine

2.2 Hold water ∴ swell up & behave like sponge on passing through gut

2.3 Add bulk to diet and ↑ transit time in gut

3. Imp. of fib.

3.1 No heart disease

3.2 ↓ cholesterol

3.3 ↓ blood glucose

3.4 Hold water ∴stools are soft, bulky & easily eliminated ∴no constipation

3.5 ↓ time of release of ingested food in colon ∴no colon cancer

3.6 ↓ desire to eat & low coefficient of digestibility ∴no obesity

4. Over consumption of fib.

4.1 Bind metals, e.g. Ca, Mg, P, Zn. ∴prevent absorption by body ∴↑ nutritional deficiency

4.2 40 g/day is desirable

Key to abbreviations:
fib.	fibres
e.g.	examples
carbs	carbohydrates
&	and
∴	therefore
↑	increase
imp.	importance
↓	reduce
Ca	calcium
Mg	magnesium
P	phosphorus
Zn	zinc
g	grams
/	per

(b) Summary:

Dietary fibres are plant carbohydrates like cereals, fruits and vegetables. Fibres cannot be digested by our body. Fibres hold water. So, they swell up and behave like sponge in the gut. They increase dietary bulk and the transit time in the gut. Fibres prevent heart disease, high cholesterol and blood glucose levels, constipation, colon cancer and obesity. Fibres bind important metals and prevent their absorption by the body. Its over consumption increases chances of nutritional deficiency. Therefore, it is advisable to consume forty grams of fibres daily.