Are You Getting Enough Vitamin D?

If you never leave the house without slathering on sunscreen, shun the sun like a Twilight-saga vampire, and rarely if ever take a multi-vitamin, chances are you’re not getting enough vitamin D.

Our bodies naturally produce vitamin D with exposure to the sun’s UVB rays, giving it the nickname the “sunshine vitamin.”  However, our computer-centric lifestyles and obsession with sunscreen mean that many people don’t make enough vitamin D.  In fact, researchers estimate that about half the world population has a vitamin D deficiency!

Why should you care?  Well to start, if you’d like to reduce the number of cold and flu bugs you get this winter, you’ll want to increase your vitamin D levels.  Vitamin D, which is actually a fat-soluble hormone and not a vitamin, is critical for optimal health, especially the health of the immune system.

A 2009 Japanese study of 350 school-age children found that children who received 1200 IU of vitamin D daily during a 4-month period contracted the flu 42% less than those who did not receive the supplement.  The children who did not take vitamin D also suffered six-times more asthma attacks!  I personally have given my son 2000 IU of liquid vitamin D daily since he was 5 and although he’s had a few minor colds during that time (he’s now 9), he’s yet to come down with any big, nasty bug (knock on wood!).  My husband claims this has to do with his superior genes, but I suspect the vitamin D may have something to do with it!

Studies have also shown that vitamin D helps to protect against many serious diseases such as cancer, heart disease, psoriasis and autoimmune conditions like multiple sclerosis.  In fact, recent studies have identified a link between higher cancer survival rates in the southern latitudes and higher vitamin D levels.

If that didn’t get your attention, vitamin D is also important for calcium absorption and bone density (helping to prevent osteoporosis) and muscle strength.  Have I convinced you yet to pay attention to your vitamin D levels?

Other than fatty fish such as salmon and cod, few foods contain vitamin D and most that claim to be high in D (such as milk and cereals) have just been enriched with a supplement that is often not well-absorbed by the body (more on supplements in a moment).

The ideal way to get your vitamin D is as Mother Nature intended:  get out in the sun!  Depending on the season, your latitude and skin color, you will need only 15 to 30 minutes to get your daily dose of D (the darker your skin and the farther north you live, the longer you need).

During the late fall and winter months, most of us produce little if any vitamin D because the angle of the sun blocks the UVB rays.  This is particularly true for areas north of 40 degrees N latitude (in the U.S., Denver, Columbus, OH, Newark, NJ and Pittsburgh are all at 40 degrees).   The rule of thumb:  if your shadow is longer than you are tall, you’re not producing much, if any, vitamin D.

Because of this so-called “vitamin D winter,” a supplement is highly recommended, especially from about November through March.  When choosing a supplement, look for vitamin D3, which is derived from animals (usually fish) and is identical to the vitamin D naturally produced by the body.  Avoid D2, which is a synthetic form that many people have difficulty digesting and metabolizing.

Vitamin D is best absorbed when taken with fatty foods, as well as some magnesium, vitamins A and K, zinc and boron.  So ideally, you’ll take your vitamin D along with a multi-vitamin at breakfast after eating some eggs.

How much vitamin D should you take?  This topic has been much debated in the medical community.  The U.S Government’s Food and Nutrition Board increased its recommended intake last year to 600 IU for children and adults up to age 70 and 800 IU for seniors 70+; however, many researchers (and nutrition coaches like me!) think this is far too low.  Vitamin D toxicity is extremely rare, with very few reported cases (usually due to a supplement manufacturing error).  There are more and more studies released each month supporting the need for higher levels of vitamin D.

I follow the advice of the Vitamin D Council, which is a non-profit research group dedicated to ending vitamin D deficiency.  For otherwise healthy adult and adolescent vampires and sunscreen lovers whose bare skin never sees the light of day, they recommend 5000 IU daily and for children over the age of one, 1000 IU per 25 lbs. of body weight.

The best way to determine dosage, though, is to get your vitamin D level tested.  This is a simple blood test most doctors are happy to order (or purchase a home-testing kit).  Your vitamin D level should ideally be at 50 ng/ml or higher.  If you’re significantly lower than that, you can take 10,000 IU for a couple of months to quickly boost your levels, then re-test to see where you’re at (because vitamin D is a fat soluble nutrient, it takes a while to build up in your blood stream).

Do you take a vitamin D supplement?  Do you know what your blood levels are?  Have any questions or concerns about vitamin D?  Post a comment and join the discussion!


  1. wrote on October 6th, 2011 at 5:43 pm

    Daddy by Default

    Great article, thanks Amy. This was a problem when I live in Seattle. No sunshine there, so we took extra vitamin D – doc actually prescribed it, along with a multivitamin to supplement. Felt good!

    Got any good tips for eating healthy while on the run with the kids? I know that’s something my readers at would love to know.

    • wrote on October 6th, 2011 at 6:25 pm


      Thanks, Craig! I’m glad the docs in Seattle are proactive about the D. I was surprised to learn that even most Hawaiians are vitamin D deficient! Eating healthy on the run is one of my favorite topics. I’m always the geeky one at soccer games munching a spinach salad packed in Tupperware! More on that to come – thanks for asking.

  2. wrote on October 14th, 2011 at 5:10 pm


    This really is an issue I must find more information about, appreciation for the post.

    • wrote on October 14th, 2011 at 6:08 pm


      Glad you liked the post. I would highly recommend checking out for more info. Great site devoted entirely to research about vitamin D.

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