NCERT Solutions Curiosity Chapter 3 –58End-of-chapter questions — Let us enhance our learning

(i) The odd one is Chana.

Jowar, bajra and ragi are all millets — small-sized cereal grains, rich in carbohydrates, and called nutri-cereals. Chana is a pulse, not a millet, and its main nutrient is protein. So it does not belong to the group.

(ii) The odd one is Rice.

Kidney beans (rajma), green gram (moong) and soya bean are all pulses/legumes and are rich sources of protein — body-building foods. Rice is a cereal whose main nutrient is starch, a carbohydrate — an energy-giving food.

Culinary practices are the ways of preparing and cooking food. They have changed a great deal in India, and both the old and the new ways have their advantages.

Why the change happened: technological development, improved transportation and better communication — and also because families have less time than before.

Ravi should ask questions that can actually be answered with evidence. Two good ones:

1. “Which diseases can be cured or prevented by food alone, without any medicine?” — the answer would be the deficiency diseases: scurvy cured by amla and lemon, night blindness prevented by carrot and papaya, goitre prevented by iodised salt, anaemia by green leafy vegetables and jaggery.
2. “If food can act as medicine, why do doctors still give tablets and syrups?” — because food works slowly and only for shortages of nutrients; an infection or a severe deficiency needs medicine as well, as in Reshma's case in question 6.

Other questions Ravi could ask:

• How long does it take for a change in diet to show an effect on health?
• Can eating too much of a “healthy” food be harmful?
• Why did James Lind's sailors get better only after eating lemons and oranges?
• Do our grandmother's remedies — haldi milk, tulsi, ginger — work in the same way?
• Which foods should a person with a fracture or a wound eat, and why?

The statement is true — taste and nutrition are two different things, and our tongue is not a good judge of health.

My thoughts: tasty junk food is fine as an occasional treat, but it cannot form the base of a diet. And a nutritious food that is disliked can usually be made likeable — karela stuffed and shallow-fried, palak in a paneer gravy, ragi as a sweet malt, bajra roti with gud and ghee.

Medu's problem is a shortage of dietary fibre (roughage) and water. Biscuits, noodles and white bread are made from refined flour (maida), from which the fibre has been removed, and he eats no vegetables at all — so almost nothing in his food helps the smooth passage of stool.

Changes he should make:

1. Eat green leafy vegetables daily — palak, methi, sarson — and other vegetables such as lauki, bhindi and carrot.
2. Eat fresh fruits with the skin where possible — guava, apple, papaya, banana.
3. Replace white bread and maida noodles with wholegrain foods — chapati of whole wheat aata, bajra or jowar roti, brown rice, dalia.
4. Add pulses and nuts — dal, rajma, chana, groundnut — which give both fibre and protein.
5. Include a raw salad and a bowl of curd with meals.
6. Drink plenty of water through the day, and cut down biscuits and packaged snacks.

(i) The deficiency disease: night blindness — that is, loss of vision in darkness. It is the well-known symptom of a shortage of Vitamin A, listed in Fig. 3.5 as “loss of vision”.

(ii) The food component lacking: Vitamin A. Vitamin A keeps our eyes and skin healthy; when it falls short, the eye cannot adjust to dim light, and in severe cases there may be complete loss of vision.

(iii) Four food items she should include:

I would prefer (iii) the fresh fruit.

Reasons for choosing the whole fruit:

• It keeps its dietary fibre, which juice loses — and fibre prevents constipation.
• It has no added sugar, preservatives or artificial colour.
• Its vitamins are intact, because it has not been heated, stored or exposed to air for long.
• Chewing the fruit makes us feel full, so we do not take in extra calories.

(i) Why calcium tablets: because calcium keeps bones and teeth healthy (Fig. 3.5). A broken bone has to be rebuilt, and calcium is the mineral from which bone is largely made. Extra calcium therefore helps the fracture heal faster and makes the new bone strong. A shortage of calcium causes weak bones and tooth decay.

(ii) Why Vitamin D was added on the second visit: because Vitamin D helps the body absorb calcium for bone and teeth health. Calcium taken by mouth is of little use if the body cannot absorb it from the food into the blood and bones. Vitamin D is the nutrient that makes that absorption possible — so the doctor gave the two together, as a team.

(iii) Questions that arise in my mind:

• Why did the doctor not give Vitamin D along with the calcium on the very first visit?
• Perhaps a test on the second visit showed that Gourav's Vitamin D was low, or the bone was healing slowly — is that why the syrup was added?
• Could Gourav have got the same Vitamin D naturally, by sitting in the morning sunlight, since our body produces Vitamin D on exposure to sunlight?
• Would milk, curd, paneer, ragi and til have supplied enough calcium without tablets?
• For how long should such supplements be taken, and can too much be harmful?

Because the iodine test detects starch only — not every carbohydrate. Sugar is a carbohydrate, but it is not starch, so no blue-black colour appears.

Carbohydrates come in more than one form:

• Simple sugars — glucose, common sugar, jaggery, honey. Sweet in taste, quickly absorbed, no reaction with iodine.
• Starch — the carbohydrate of rice, wheat, potato and bajra. Not sweet, digested slowly, turns blue-black with iodine.

Raman's statement is completely correct. Starch is one kind of carbohydrate, so every starch is a carbohydrate; but sugars such as glucose, common sugar and jaggery are also carbohydrates and they are not starches.

Design of the activity to test it:

1. Collect samples that are all known to be carbohydrates: boiled rice, a slice of potato, a piece of chapati, common sugar, jaggery, honey and glucose powder.
2. Keep each sample on a separate clean dish and note its original colour.
3. Add 2–3 drops of dilute iodine solution to each with a dropper.
4. Observe the colour after a minute and record it in a table.
5. Analyse: rice, potato and chapati turn blue-black — they contain starch. Sugar, jaggery, honey and glucose show no blue-black colour, although all of them are carbohydrates.

The saree must have had starch in it, and the socks did not.

Why a saree would contain starch: cotton sarees are usually starched after washing — a paste of rice water or arrowroot (kanji) is applied so that the saree becomes stiff, crisp and easy to drape. That starch stays in the cloth, so the iodine finds it at once.

Why the socks did not change colour:

• Socks are usually made of synthetic fibre or woollen/cotton knit and are never starched — starch would make them stiff and uncomfortable.
• Even if they were cotton, they had been washed and worn many times, so any starch would have gone.

Why millets are a healthy choice:

• They are highly nutritious grains — good sources of vitamins, minerals such as iron and calcium, and dietary fibres. That is why they are also called nutri-cereals.
• The fibre keeps digestion smooth and prevents constipation, and the energy is released slowly and steadily.
• They are native crops of India and have been an integral part of the Indian diet for centuries.
• They can be easily cultivated in different climatic conditions and need little water, so they grow in dry regions where rice cannot.
• Being locally grown, they also have low food miles.

Can millets alone be enough? No. Millets contribute significantly to a balanced diet, but they cannot make a balanced diet by themselves.

Test it on a food that is known to contain starch. That is the safest way, because we already know what iodine does to starch.

The procedure:

1. Take a small piece of a known starchy food — boiled rice, a slice of raw potato or a piece of bread — and keep it on a clean dish.
2. Note the colour of the given solution. Dilute iodine solution is light brown or yellowish-brown.
3. Using a dropper, put 2–3 drops of the given solution on the food.
4. Observe for a minute.