FUNCTIONS AND SOURCES OF SOME VITAMINS

Vitamin A:

· Vitamin A plays a vital role in vision in dim light, in the retina of the eye. Retinol supplied to the retina in the blood is converted to retinal, which then combines with a protein called opsin to produce a purple pigment known as rhodopsin.

· Vitamin A aids in the formation of healthy teeth, skeletal and soft tissue, mucous membranes and the skin

· Vitamin A is required to maintain the normal health and function of epithelial layers, which provides the first line of defense against invading microorganisms.

· Vitamin A is also required for reproduction and breastfeeding.

SOURCES: The body can obtain vitamin A from carotene, a vitamin antecedent found in vegetables like sweet potatoes, broccoli, green leafy vegetables, yellow and orange fruits and vegetables like mango, papaya, and carrots.

Vitamin D:

Also known as the ‘sunshine vitamin’, our bodies are able to produce this vitamin by exposure to sunshine. Vitamin D helps in the absorption of calcium and phosphorous and is thus essential for bone formation and for healthy teeth.

SOURCES: Most foods have negligible amounts of Vitamin D. Certain marine fishes are known to be good sources of vitamin D. Egg yolk, butter and milk have some vitamin d and can be considered as poor sources.

Vitamin E:

· The main function of vitamin E is to act as an antioxidant within the body. Antioxidants are substances that protect other chemicals of the body from damaging oxidation reactions by reacting with oxidizing agents within the body.

· Helps breakdown of polyunsaturated fats.

SOURCES: Vegetable oils are the richest source of Vitamin E apart from that green leafy vegetable and whole-grain cereals are sources of vitamin E.

Vitamin K:

The only known function of Vitamin K is its use by the liver in the synthesis of various substances needed for blood clotting. Among these substances are prothrombin factor II, proconvertin factor III, plasma thromboplastin component factor IX, and Stuart factor, factor X.

SOURCES: Dark green leafy vegetables, fruits, tubers, seeds, and dairy and meat products are rich sources of Vitamin K.

Vitamin C:

· Vitamin C is a biological reducing agent especially during hydroxylation reactions and it is an antioxidant that protects the body against damaging oxidizing agents.

· Vitamin C plays an important role in maintaining healthy teeth and gums.

· It also aids in the absorption of iron.

· It is important for the formation and maintenance of collagen, the connective tissue that supports many-body structures.

SOURCES: Citrus fruits like oranges, gooseberries, grapes, lemon, lime, etc., green leafy vegetables, broccoli, cabbage, tomatoes are good sources of Vitamin C.