Vitamin A (retinol)

Vitamin A is found in milk products and eggs, fish oils and vegetables, particularly carrots. It is needed for stimulating healthy growth and for good vision, so any gross vitamin A deficiencies can cause stunted growth, night blindness and in extreme cases even blindness. Xerophthalmia (a degenerative drying of the cornea)

can be caused by a vitamin A deficiency. It is a vital part of rhodopsin, the visual pigment of the eye.
Another name for vitamin A is retinol, and its chemical structure contains a molecule with many unsaturated C C bonds and also a CH2OH alcohol group. It is a fat-soluble vitamin. Large doses of vitamin A have been linked to some birth defects so many pregnant women are advised to avoid food supplements rich in vitamin A.

Cod liver oil, containing vitamin A, was often given to young children to supplement their diets. This was particularly true in the UK during World War II, when food was in short supply. I can still remember the bribes I demanded for taking such a revolting liquid with its evil smell and taste. I still shudder at the thought of it even as I write this! Cod liver oil is now recommended for people with arthritis as it is incorporated into the cartilage cells and helps prevent their break-down.1 This property depends more on the fatty acids present than vitamin A.