Vitamin A, also known as retinol, is an important substance in the retina that allows you to see in twilight. Beta-carotene, a precursor of vitamin A found in vegetables, has antioxidant properties, which means that it protects cells from oxidative damage.
Vitamin D is a fat-soluble vitamin. It is known as the “sunshine vitamin”, which protects the body from UV exposure. Vitamin D becomes the hormone clacitriol in the kidneys, which is actually its most active form. The action of this hormone is directed towards the intestines and bones. The main biological function of vitamin D is to maintain normal levels of calcium and phosphorus in the blood. Vitamin D helps in the absorption of calcium and maintains healthy bones. It contributes to bone mineralisation along with several other vitamins, minerals and hormones. Without vitamin D, bones can become brittle, soft or misshapen. It protects the body against skeletal dysfunction such as rickets in children and asteoporosis in adults.