The Importance of Getting Enough Vitamin D

When I was in medical school, I think Vitamin D was mentioned only once or twice.  As a new physician (a great number of years ago now), I really did not recognize its importance and never routinely tested Vitamin D levels in patients.  Later, after educating myself about this, I began doing so and was amazed at how many people had low levels. Here I was practicing in Santa Clara, California (next door to Sunnyvale - nearly 300 sunny days per year), and low Vitamin D levels are more the norm than not. What’s the deal?
Who Has Low Vitamin D Levels?

There probably was a time, not so long ago, when low Vitamin D levels were not an issue. More people had outdoor jobs and spent more time overall outside in the sun. Fresh sunshine on our skin is the major way that our bodies make Vitamin D.

With the advent of computers and the fact that most jobs (mine included) involve entering data into those machines all day, most of our light comes from those attractive energy-saving bulbs over our heads in the office. Combine that with the fact that we are terrified of skin cancer and slather on SPF 99 and wear hats to protect us from the cancer-producing rays of the sun and few of us are set-up to produce much Vitamin D at all.

It is probably safe to say that we were not designed to sit indoors in front of a computer screen all day. Our ancestors spent much more time outdoors in the sun and probably did not have access to SPF-anything. Our Vitamin D producing capacity likely evolved taking this much greater sun exposure into consideration. Now many of us have low levels and there really should be no mystery as to why.

VItamin D levels also vary with where you live - the further you are from the equator the less direct sunlight you receive. Canadians have lower Vitamin D levels than Americans. Also, if you have darker skin your levels will be lower. In Silicon Valley, those from India often have very low Vitamin D levels. Vitamin D comes mainly from animal sources and Vegans can have low levels as well. Finally, seasonal variations occur as well with lower levels occurring in the winter months.

Why is Vitamin D Important?

The main function of Vitamin D is to get calcium into your bones. Osteoporosis, or low-bone density, can result from not having enough Vitamin D. Vitamin D has also been associated with cardiovascular disease, certain cancers, diabetes, and hypertension. In my clinic I have some patients who swear it helped their skin, hair, and depression. Interestingly, Vitamin D is also needed to make testosterone, estrogen, and growth hormone.

Get Tested

A simple blood test will determine if you have low levels. The preferred blood test is the Vitamin D 25-OH level and we routinely do this as part of a complete physical examination. Vitamin D levels are measured in ng/ml and are quantified as follows:

<20: Deficiency
20-29: Insufficiency
30-99: Normal
100-150: Excess
>150: Toxicity

Unfortunately, there is great debate about what is normal and “ideal.” It seems that anything less than 30 is not enough for basic processes and that 40-60 is probably the “desirable” range for optimal functioning. Remember, as with most things, more is not necessarily better and can be harmful.

How To Supplement

Vitamin D (along with Vitamin A, D, and K) is a fat-soluble vitamin and needs to be taken with fat in your stomach or you will not absorb it. Eggs, nuts, avocado, or any other fatty food will do. Do not just wake up, drink a glass of water, and take your Vitamin D - you will not absorb it.
Vitamin D comes in international units (IU) and the preferred form for supplementation is Vitamin D3. The recommended daily allowance (RDA) is 400 IU but typically this is not enough if your levels are low. Also, there is not enough Vitamin D in a multivitamin and additional Vitamin D is often required. A good general rule of thumb is that if your levels are between 20 and 30, use 2,000 IU, and if you are lower than 20, consider using 5,000 IU.

There is not much difference in the Vitamin D supplements on the market. If your levels are still low despite supplementing, consider adding Magnesium and/or Vitamin K2 as these can help with absorption. Retest your levels after a few months. Now, go get tested and do something about it!

Dr. Jeffrey Blue, MD



Your comment will be posted after it is approved.

Leave a Reply