Biomolecules
Vitamins
Classify vitamins and link them to diseases.
Vitamins are organic compounds that our bodies need in small amounts for normal growth and health, but mostly cannot make. They must come from food. A shortage of one causes a deficiency disease.
They are sorted by what they dissolve in:
- Fat-soluble: A, D, E and K. They are stored in the liver and in fatty tissue, so we do not need them every day.
- Water-soluble: the B group and C. They are not stored: any extra is washed out in urine, so they must be eaten regularly. (Vitamin B₁₂ is an exception: the liver can store it.)
The main ones, their sources and what happens without them:
| Vitamin | Good sources | Deficiency disease |
|---|---|---|
| A | Fish liver oil, carrots, butter, milk | Night blindness; xerophthalmia (hardening of the cornea) |
| B₁ (thiamine) | Yeast, milk, green vegetables, cereals | Beri-beri |
| B₂ (riboflavin) | Milk, egg white, liver | Cracked lips and sore tongue |
| B₆ (pyridoxine) | Yeast, milk, egg yolk, cereals | Convulsions |
| B₁₂ | Meat, fish, egg, curd | Pernicious anaemia |
| C (ascorbic acid) | Citrus fruits, amla, green leafy vegetables | Scurvy (bleeding gums) |
| D | Sunlight on the skin, fish, egg yolk | Rickets in children; soft bones in adults |
| E | Vegetable oils, sunflower oil | Fragile red blood cells, muscle weakness |
| K | Green leafy vegetables | Blood does not clot properly |
A, D, E and K dissolve in fat; B and C dissolve in water.
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