Vitamin A is a fat-soluble vitamin and its functions are to improve vision and prevent clinical eye disease called xerophthalmia, maintain healthy skin, ensure the growth of healthy teeth and bones, and enhance the immune system. Fortified milk, butter, eggs, liver, and cream are animal sources of vitamin A while green vegetables, pumpkin, carrots, and apricots are plant sources of vitamin A.
Vitamin D is another fat-soluble vitamin and its functions are homeostasis of calcium and phosphorus levels in the blood, absorption of calcium from the gastrointestinal tract and resorption from bones, and strengthening of bones to prevent osteoporosis and osteomalacia. Fish, eggs yolk, fortified milk, liver, and red meat are primary sources of vitamin D.
Vitamin B is a complex of vitamins, which are soluble in water and they have numerous functions in the body. Vitamin B complex is important in cellular metabolism, production of energy, and oxidation of carbohydrates for they act as coenzymes and cofactors. Sources of the vitamin B complex are milk, green vegetables, liver, fish, cereals, legumes, nuts, and fruits. The functions of vitamin C are it promotes the absorption of iron, acts as a coenzyme in the metabolism of proteins, and boosts immunity. Overall, vitamins that have antioxidant activity are vitamin A (β-carotene), C (ascorbic acid), and E (tocopherol).
As a mineral, the functions of calcium are the formation of strong bones and teeth, contraction and relaxation of muscles, transmission of impulses, and regulation of blood pressure. Fish, milk, greens, soy milk, and legumes are some of the sources of calcium. As another mineral, the functions of phosphorus are to strengthen bones and teeth and homeostasis of pH. The common sources of phosphorus are eggs, milk, meat, and fish.