Nutrient Deficiency Diseases

Night blindness or the difficulty of seeing in dim light is caused by a deficiency in vitamin A which helps in the formation of visual purple needed by the eyes for night vision. The deficiency can also cause glare blindness when the eye is either exposed to too much light or a sudden change in the amount of light when entering a darkened room. Another eye disease caused by vitamin A deficiency is xerophthalmia which can lead to blindness. This condition affects the cells of the cornea, other eye tissues, and the tear ducts, which stop secreting.

Vitamin A deficiency can create a number of adverse skin conditions, problems with tasting and smelling, and it may also cause difficulties with the reproductive system.

Vitamin E and K deficiencies are rare. Vitamin E protects against substances that oxidize quickly and vitamin K promotes normal blood clotting. Vitamin B₁₂ (cobalamin) provides protection against pernicious anemia and mental disturbances. Vitamin B₆ can also protect against anemia as well as dermatitis, irritability, and convulsions.