Lack of vitamins can acuse deficiency diseases. The syllabus wants you to know the impact of vitamin A and D deficiencies. What major conditions are caused by deficiency in these two vitamins?
Vitamin A > NIght blindness and xerophthalmia
Vitamin D > Osteomalacia and rickets
Vitamin A Deficiency
Sources of vitamin A is found in > milk, eggs, liver, fish-liver oils, mango and papaya, cabbage, carrots and spinach.
The liver stores sufficient vitamin A to last for 1-2 years.
Children with vitamin A deficiency suffer from night blindness (it helps the rod cells to function) and xerophthalmia- a drying and scarring of the cornea. The disease is thought to be the cause of half a million cases of childhood blindness across the world.
Vitamin D Deficiency
Vitamin D comes from the diet- in the following foods > eggs, oily fish, margerine, meat and meat products. It is also made by the skin when exposed to sunlight- hence its alternative name: the sunshine vitamin. It is stored in the muscles and fat, and reserves are normally enough to get people through the winter months. People who are house-bound or covered up are at risk of deficiency.
Vitamin D is vital for the uptake of calcium from the intestine. It also regulates the deposition of calcium.
Deficiency in children can lead to > rickets. In adults it causes > osteomalacia. This is a progressive softening of the bones making them susceptible to fracturing. Women are particularly susceptibe, especially those with a diet poor in vitamin D and having large numbers of breast-fed children.