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Science · Class 9-10 · Chapter 1 · 1.1.4 Vitamins

Vitamins.

Vitamins are those organic parts of food that are wanted in the smallest amounts, that give no energy and build no tissue, and without which the chemistry of the body will not run and certain diseases appear. The Bangla name for them is খাদ্যপ্রাণ. This is the part of the chapter that leans most on memory, so the work here is to turn the memorising into a structure.

1. Why a pinch is enough

A vitamin is not raw material for anything. It helps the body's enzymes to do their work and then stands aside, so the same molecule may serve again and again. A pinch is enough; a bowlful is not wanted.

The book divides them by what they dissolve in. A, D, E and K dissolve in fat; the B complex and C dissolve in water. The division is not a matter of names only: three real consequences follow from it, and all three get asked about.

sort them a chip, then a bin

Ten vitamins in two groups

Pick up a chip, then drop it in a bin. Only four dissolve in fat; all the rest in water.

2. The whole table

Ten rows and four questions: what it dissolves in, where it is found, what it does, and what happens without it. Tap the name of a vitamin and the whole of it comes up below.

the table tap the name of a vitamin

The table of vitamins

namedissolves infound inits workwithout it
Afatcarrot, eggsightnight blindness
Dfatsun, yolkbonerickets
Efatplant oilscellsinfertility
Kfatgreen leavesclottingbleeding
B₁waterunpolished ricenervesberiberi
B₂watermilk, greensskinmouth sores
B₅watermeat, nutsskin, nervespellagra
B₆waterrice, fishbloodanaemia
B₁₂waterliver, eggblood, nervesanaemia
Cwateramloki, lemonhealingscurvy
Vitamin A, dissolving in fat. From animals: eggs, milk, butter, curd, ghee and liver. From plants: carrot, red amaranth, ripe papaya and mango, where it is present as beta carotene and the body turns it into A. Its work is to keep the sight and to grow the body. Without it comes night blindness, the failing of sight in low light, and in time xerophthalmia, the drying of the eye and ulcers on the cornea.

Niacin is written here as B₅, as the lists following this book have it; in international naming it is B₃. Whether this section gives the source and the work of vitamin K could not be checked, so that entry is kept short.

3. The eye in low light

Everyone knows the name night blindness and few know what it is like; many take it for blindness altogether. Drag the handle and see.

two layers drag the handle

The yard at dusk

Night blindness is not blindness. In daylight everything is seen as it always was, but when the light falls the eye will no longer adjust, because the pigment the retina needs for seeing in low light is made from vitamin A. Let the want run on and the eye dries and xerophthalmia may follow. The good of it is that carrot, red amaranth, ripe papaya, mango, eggs and milk all carry this vitamin, and none of them is hard to come by.

4. How many vitamins on one plate

After the table it may seem that each one calls for something of its own. The opposite is true. Tap the numbers on an ordinary midday plate and see.

the plate tap a number

A plateful of vitamins

Chiefly carbohydrate, but where the rice is little polished it brings vitamin B₁ as well. Polished hard, the B₁ goes with the outer layer, and in time beriberi may follow.

5. Saving vitamins in the kitchen

That a food holds a vitamin is one thing; that the vitamin reaches the plate is another. The kitchen lies between, and much is lost there. Every one of the six habits below follows straight from the rule about what dissolves in what.

the kitchen tap a habit

How the vitamins are lost

The B complex and C, which dissolve in water, go out with the water that is thrown away. Used in the gravy, or cooked covered in a little water, much of it stays.

These kitchen habits are not the book's examples; they are applications worked out from the rule about solubility.

cards tap a card

Which want brings which disease

illnessNight blindness
want of whatThe want is of vitamin A. The sign is not seeing in low light. Found in carrot, red amaranth, ripe papaya, eggs and milk.
illnessXerophthalmia
want of whatThe want is of vitamin A, over a long time. The signs are the drying of the eye and ulcers on the cornea. The sources are those of night blindness.
illnessBeriberi
want of whatThe want is of vitamin B₁. The signs are weak nerves, tingling in the hands and feet, and weak muscles. Found in unpolished rice, lentils, nuts and eggs.
illnessPellagra
want of whatThe want is of vitamin B₅, niacin. The signs are sores on the skin and trouble with the digestion. Found in meat, liver, flour, lentils and nuts.
illnessScurvy
want of whatThe want is of vitamin C. The signs are bleeding gums, teeth lost early, and wounds slow to heal. Found in amloki, lemon, guava and tomato.
illnessRickets
want of whatThe want is of vitamin D, with calcium and phosphorus. The sign is soft and bending bone in children. Found in sunlight, egg yolk, milk and oily fish.
illnessOsteomalacia
want of whatThe want is of vitamin D. The signs are soft and aching bone in adults. The sources are those of rickets; the difference is one of age, rickets in children and osteomalacia in adults.
illnessAnaemia
want of whatThe want is of iron, or of vitamin B₆ or B₁₂. The signs are pallor, weakness and quick tiring. Found in greens, liver, fish, meat, eggs and lentils.

Nobody is at fault for these. Often the food simply is not to be had, and that is the whole of it; so the mending of them is usually nothing difficult, only more variety.

check yourself

One question

Which group holds only vitamins that dissolve in fat?

check yourself

Another question

Someone's gums bleed often and cuts are slow to heal. Which vitamin is most likely wanting, and where is it easily had?

check yourself

Last question

What sets vitamin D apart from all the others?

At a glance

What they are. Wanted in the smallest amounts; they give no energy and build nothing; and without them the chemistry will not run.

Two groups. A, D, E and K dissolve in fat; the B complex and C in water.

Four diseases. A brings night blindness and xerophthalmia, B₁ beriberi, B₅ pellagra, C scurvy; and D rickets and osteomalacia.

D is the exception. The only one the body can make for itself, with sunlight. And too much of it does harm as well.

If your body or your eating is worrying you, talk to an older person at home or to a teacher at school; if it is needed they will take you to a doctor.

Source: Science, Classes 9-10 (NCTB), Chapter 1 “A better way of living”, section 1.1.4. The kitchen applications are worked out from the rule about solubility and are not the book's examples.