Sunlight represents the best source of vitamin D because human skin converts sunlight into the nutrient, according to WebMD. However, people at risk for skin cancer may need to avoid sunlight. Fortified foods in the American diet, such as dairy, cereal and yogurt, also contain vitamin D. Patients can take supplements to ensure they get enough vitamin D in their diet as well.
Expose your skin to direct sunlight to get enough vitamin D daily, says the Vitamin D Council. Your body produces enough vitamin D in about half the time it takes the skin to turn pink due to sunburn. For fair-skinned people, this could happen in as little as 15 minutes, whereas darker-skinned people may require two hours or more to receive enough vitamin D every day. Your body makes between 10,000 and 25,000 international units of vitamin D within the time frame it takes your skin to turn pink due to sunlight exposure. Where you live may determine how much vitamin D your skin makes during various times of the year.
Foods that contain natural amounts of vitamin D include mushrooms, salmon, tuna, beef liver and egg yolks, notes Health.com. One serving of fatty fish, such as mackerel, tuna or trout, may contain up to 450 international units of vitamin D, just 150 international units short of the 600 international units recommended by the Institute of Medicine as of 2015.