Vitamin D is also super important for bone health because it helps the body absorb calcium from food. You can get vitamin D from wild-caught salmon, tuna, and mackerel and fortified dairy, juices, and eggs. Also, your skin makes vitamin D when exposed to the sun's rays. However, most of us don't live in perpetual summer, and when we are in the sun, we wear sunscreen, which protects us from burns, wrinkles, and skin cancer, but also stops the skin from making vitamin D. Since so few foods offer much of the vitamin and most of us don't get much sun exposure, "it's pretty clear that everyone who doesn't take vitamin D supplement is deficient," Recker says. But don't even think about skipping sunscreen – instead, Recker suggests supplementing with at least 1,000 IU of vitamin D a day. He strongly prefers vitamin D3, the type that comes from animals, but the plant-based version, vitamin D2, has also been shown to support bone health.