Vitamin D3 is the fat-soluble activator essential for dental health, bone growth, controlling the immune system, brain development, and maintaining cardiovascular health. The best sources of D3 are sunlight, animal organs, fatty fish, and raw cheeses, which is why many people today are perilously deficient. When you don’t have enough D3 the body cannot direct calcium or phosphorus to remineralize teeth and bones, no matter how much of these essential minerals you consume.