Vitamin D

Throughout the summer and early fall, we can get the recommended amount of vitamin D that we need by getting 10-15 minutes of sunlight (without sunscreen) per week. Those with darker skin will need a little more than that. That amount of sunlight will give us 10,000 IU of vitamin D, which can be stored.

However, in November through February, the sun doesn't get high enough in the sky in Missouri for us to get the vitamin D that we need. Getting the right amount of vitamin D from foods is very difficult because there is only small amounts in some dairy products (milk is the biggest source), eggs, fatty fish (salmon, sardines), and other fortified products (orange juice and cereal for example). Vitamin D will be listed on the nutrition label, so look there to find out how much you are getting. The percent daily values are based on 400 IU, so 25% Daily Value would equal 100 IU.

A supplement of vitamin D may be necessary, especially in the winter months. Some experts recommend 1,000 to 2,000 IU daily. Vitamin D can be stored, so if you forget to take it once in awhile, it's not a big deal. Vitamin D supplements are fairly inexpensive (look for deals at drug stores or online, at Walgreen's sometimes you can get buy one get one free) and is best taken with calcium or dairy foods. Vitamin D helps with calcium absorption and is also related to many other health benefits, for example: diabetes prevention, cancer prevention, heart disease prevention, immunity, prevention of depression, and muscle strength. If you are going to take a supplement, talk with your physician first to make sure there will be no drug interactions. A physician can also test the vitamin D levels in your body, so ask them if you are interested.

The vitamin D recommendations were changed in 2010. Vitamin D is typically measured in IU or International Units. Infants up to age 1 need 400 IU daily; children (age 1 and up), adults (up to age 70), and women who are pregnant or breastfeeding need 600 IU daily. Adults age 71 and up need 800 IU daily. Some experts will argue that those recommendations should be higher.

The tolerable upper level intake, or the most you can safely take, is set at 4,000 IU but research has shown no toxicity at levels below 10,000 IU. You would have to take a large amount of a vitamin D supplement to reach that toxic level, sunlight will not give you a toxic amount of vitamin D.


Older adults, those who always wear sunscreen, those who stay indoors, and obese individuals have a greater risk for vitamin D deficiency. Older adults and those who are obese don't absorb the nutrient as well, so they may need a higher intake of the supplement to reach the optimal level.


The Linus Pauling Institute from Oregon State University has great information on vitamin D, as does this blog posting from May 2010.