Quest Vitamin D3 - 1000IU Tablets (90). Vitamin D is a fat-soluble vitamin that is required to promote calcium absorption, which helps to maintain healthy bones and teeth.. Obtained from the sunlight or vitamin D rich foods - over a billion people worldwide have very low levels of vitamin D. In addition to changing your diet and lifestyle, taking a vitamin D supplement is a good way to top up, especially in winter months.. Vitamin D contributes to:. Normal function of the immune system. Maintenance of normal bones and teeth. Normal absorption of calcium and phosphorus. Normal blood calcium levels. Maintenance of normal muscle function
