What Are the Major Sources of Vitamin D?
Outside the body, vitamin D comes from three major sources: the sun, food, and supplements. Sunlight is considered to be the best source of vitamin D for your body, followed by foods that contain vitamin D, and finally, vitamin D supplements.
Vitamin D from the sun
The sun has provided vitamin D for thousands of years. However, the sun is also known to cause skin cancer, photo-damage, wrinkles, and other problems. The challenge is striking the right balance between getting enough sun for your vitamin D needs and avoiding sun damage.
Even still, most dermatologists believe that there is no “safe” level of sunlight exposure and that the sun should not be relied upon as a source of vitamin D.
Four major factors determine the effect of sunlight on your vitamin D level:
Time of year: In the summer, the sun’s rays are more direct. Direct rays much more effectively raise your skin production of vitamin D.
Your latitude on the Earth: Latitudes closer to the equator get direct sunlight for a longer time each day and for more months out of the year.
Obstacles to sun exposure of your skin: Whether it be clouds, dark skin color, smog, a hat, an umbrella, or suntan lotion, anything that limits the exposure of your skin to ultraviolet light significantly reduces your production of vitamin D in the skin.
Altitude: The higher you are, the less atmosphere there is to block the sun’s rays.
Any factor that reduces the amount of ultraviolet light that reaches your skin will reduce the amount of vitamin D produced in the skin.
Vitamin D from foods
Only a few foods contain enough vitamin D to make eating them solely for this reason worthwhile. Food manufacturers are fortifying many foods with extra vitamin D. The richest food sources of vitamin D include the following:
Cod liver oil
Vitamin D-fortified foods can provide enough vitamin D only for babies and toddlers, whose requirements are relatively small.
Vitamin D supplements
With the tremendous growth of knowledge about vitamin D and its effects, there has come an abundance of supplements in every size, shape, and form. If you can’t get enough vitamin D from your diet, you can get all the vitamin D you need from supplements.
Now that vitamin D is such a hot commodity, different preparations are becoming available. Unfortunately, the price is also going up. But vitamin D still may be the biggest health bargain around: In many pharmacies, vitamin D sells for a few pennies for 2,000 IU.