| Vitamin D
This vitamin is essential for the maintenance of normal calcium and phosphorus levels in the blood for normal bone formation and growth. It also protects the teeth and bones against the effects of low calcium intake by making more effective use of calcium and phosphorus. Also called the sunshine vitamin because it is formed in the body by the action of sunlight on the skin, vitamin D is obtained from egg yolk, liver, tuna, and vitamin D-fortified milk. Vitamin D deficiency, or rickets, occurs only rarely in tropical climates where sunlight is abundant, but it was once common among children of northern cities before the use of vitamin D-fortified milk. Because vitamin D is fat-soluble and stored in the body, excessive consumption can cause vitamin poisoning, kidney damage, lethargy, and loss of appetite.