Vitamin D and vitamin K2 are very important for your bones. They help prevent or treat osteoporosis: Vitamin D helps your body absorb the calcium your bones need. Vitamin K2 helps your body put the calcium into your bones and protects your circulation by preventing vascular calcification. Of course, your bones also need calcium as well. There are many other benefits to vitamin D, including protecting you from Covid-19 and other lung infections (click on the links).