The skin can produce all the vitamin D a body needs with 15 minutes of sun exposure daily, but many people are concerned about the risk of skin cancer.

Dr. Jo Ann Carson, a clinical nutritionist at the University of Texas Southwestern Medical Center in Dallas, says dietary vitamin D offers a solution for people who are at high risk of skin cancer or who just don't want to take any chances.

Foods rich in vitamin D include fatty fish, including salmon and tuna, shiitake mushrooms, egg yolks and vitamin D-fortified dairy products, includingk milk.

Taking a vitamin D supplement every day can also help, but don't take more than 1,000 IU per day, Carson said. In addition, be sure to take the form called cholecalciferol, or vitamin D3, because it results in the most active vitamin D in the body, she said.