To Your Health
July, 2007 (Vol. 01, Issue 07)
Vitamin D From the Sun
For most people, 10-20 minutes of sunshine can yield approximately 10,000 to 20,000 IUs of vitamin D each day, depending on the time of year and your geographical location. At high latitudes, sun exposure isn't enough to produce vitamin D between the months of October and April. The amount of vitamin D you get from the sun can vary greatly, depending on other factors including time of day, pollution, cloud cover, sunscreen, skin color, age and weight. Here are some of the statistics:
Sunscreens as low as SPF 18 decrease vitamin D synthesis by 97.5 percent.
- During winter, sunlight provides no vitamin D to the skin at latitudes above 35 degrees.
- Older adults have approximately 25 percent of the capacity to produce vitamin D compared to young, healthy adults.
- African Americans require 5-10 times longer sun exposure than Caucasians to produce similar amounts of vitamin D in the skin.
Safe sun exposure is important when considering vitamin D for health. The Food and Nutrition Board recognizes the importance of sun exposure to achieve vitamin D requirements, and says that between 10-15 minutes of sun exposure (without sunscreen) per week is adequate for most individuals. It also recommends that individuals use a sunscreen with an SPF of at least 15 for any exposure beyond that time.
| Adequate intake of vitamin D (based on age) |
| Source: Food and Nutrition Board of the Institute of Medicine. |