What are the proven advantages of taking vitamin a, b, d and zinc?

Many. These are essential vitamins that are important for metabolism and overall health. Vitamins a, e , c and zinc are associated with lower risk of macular degeneration. Taking b vitamins lowers your risk of certain types of heart disease and stroke. Be careful about taking hyper doses of vitamins a, e, d and k as these fat-soluble vitamins can accumulate in your system.