Recognising vitamin deficiency

A vitamin deficiency is often first noticed by a visible outward sign. Here are some of them.

Visible sign	Where	Likely shortage
Poor sight in the dark, white spots on the eye	Eye	Vitamin A
Cracked, sore corners of the mouth	Mouth	Vitamin B
Patchy loss of skin colour	Skin	Vitamin B
Red, bleeding gums	Teeth and gums	Vitamin C
Bowed legs, weak bones	Bones	Vitamin D

An important caution

These signs are not a diagnosis. The same sign can have several causes. Only a doctor can confirm an actual deficiency.

Chapter summary

The main substances building living bodies are carbohydrates, proteins, lipids and nucleic acids. They are called biological molecules.
Besides the organic compounds, inorganic ones such as water and mineral salts also play an important part in a living system.
The main chemical elements that biological molecules are built from are C, H, O and N.
The proteins that catalyse biochemical reactions are enzymes.
Minerals and vitamins are needed only in small amounts, but without them living things show various deficiency symptoms.
The special properties of water are enormously important for sustaining life.