The combination of vitamins K and D has been shown to significantly increase bone mineral density (BMD) better than either alone. Vitamin D has also been shown to increase bone density and to reduce hip fracture by 43-60%.

People with the highest vitamin D levels are 36% less likely to have macular degeneration. Vitamin A deficiency may cause, and supplementation may improve, night blindness. Vitamins D and A are also good for your skin. Vitamin D can help adults with low levels of D and children treat eczema, and high-dose vitamin A has been shown to prevent acne.

Vitamin K supports activation of proteins involved in tooth mineralization. People with the highest levels of D have 30% less risk of gingivitis. Vitamin D also helps periodontal disease because men with the highest levels of D have 39% less bone loss and women have 26% less: supplementation with vitamin D reduces bone loss.