April 2009

Vitamin D is a media darling these days with lots of new research coming out showing its benefits beyond bone health. Two reports presented at the annual American Association for Cancer Research meeting in 2006 point to D’s potential for reducing the risk of breast cancer. Other reports hint that D may lower the risk of other cancers such as prostate and colon cancers and multiple sclerosis.

Important New Findings:

  • We need more vitamin D than the present recommended levels. The “daily value” for vitamin D is 400 IU’s (International Units). But that level is not based on the newest studies.

  • Vitamin D experts now believe we need at least 1000 IU’s a day to keep blood levels at a healthy level.

  • Vitamin D3 (“cholecalciferol”) is better at keeping your blood levels up than vitamin D2 (“ergocalciferol”). Most multivitamins, calcium plus D supplements, and vitamin D supplements use vitamin D3 because it is more effective.

Here’s what you should do to get your vitamin D:

  • Aim for 1000 IU’s of Vitamin D a Day. As you’ll see below, you’ll probably need to get most of that from your dietary supplements.

  • Sun Can Help, But Don’t Rely on It. Some experts are recommending more time in the sun to boost vitamin D. It takes about 15 minutes of sun on the arms and face two to three times a week to get what you need. But even you spend time in the sun, you may not be making enough vitamin D because:
    1. If you wear sunscreen, you block much of the vitamin D production. An SPF of eight can lower your vitamin D production by 95%!

    2. The darker your skin, the less vitamin D you will make. African Americans are more likely than Caucasians to be vitamin D deficient because the melanin in darker skin acts as a natural sunscreen.

    3. The older you are, the less likely you are to make as much vitamin D from the sun.


      The bottom is don’t count on the sun as your source of vitamin D.
  • Check Your Multivitamin. If you take a multivitamin, you’re most likely getting some D from it. Most multivitamins have at least 400 IU’s but some have more. “Over 50” multivitamins often have 500 IU’s in one tablet. Women’s multivitamins often have 800 IU’s.

  • There Aren’t Many High Vitamin D Foods! A 3 ounce serving of salmon has about 340 IU’s of vitamin D. Egg yolks have 25 IU’s. A cup of milk or other fortified beverage has 100 IU’s. Get the picture? You’re not likely to get much vitamin D from your food.

  • Check Your Calcium Supplements. Most calcium supplements have D added. Read the label carefully – especially the serving size - to find out how much D is in each tablet. Most calcium plus D tablets have 200 to 400 IU’s of vitamin D each.

  • Milk and D-added Juice. Milk, most soy and rice milk, and some orange juices are fortified with vitamin D. One cup of each contains 100 IU’s of vitamin D (it will say “25% of the daily value” on the label but that is 25% of the daily value, which is a too-low 400 IU’s).

  • Vitamin D supplements. If you’re still not getting enough D after you check your supplements and add in what you may be getting from fortified foods, you can add on a separate vitamin D supplement. Vitamin D supplements usually come in doses of 400 to 2000 IU’s per pill. Look for plain vitamin D supplements with no added vitamin A – just the D. Too much vitamin A (beyond what you get in your multivitamin and your foods) may weaken your bones and increase your chances of a break!

While vitamin D is crucial for calcium absorption, you don’t have to take vitamin D at the exact same time that you take your calcium. Vitamin D is always in your bloodstream – so it’s always there to help absorb calcium from your intestines into the blood and then to your bones! So while it is important to spread out your calcium throughout the day, you don’t have to worry about timing with your vitamin D.

Questions? Call the University of Alabama at Birmingham’s Tone Your Bones Hotline at 1.888.934.DIET.