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My doctor said that my vitamin D level is low. Is that really bad?

Posted: December 11, 2012

(4) Comments


It's well established that Vitamin D is important in the regulation of the body's calcium levels and bone development.  If people don't get enough, they are at risk of diseases like rickets and osteoporosis.  But researchers have more recently discovered that vitamin D receptors are found on almost all tissues of the body.  This has caused a "boom" in vitamin D research; scientists are investigating its role in everything from heart disease and diabetes to depression, cancer and the common cold. 

You get Vitamin D in two ways: by consuming it in foods or supplements, and by making it in your skin when sunlight hits it.  Vitamin D doesn't occur naturally in a lot of foods - unless you're a really big fan of cod liver oil or mackerel, you wouldn't get nearly enough - so many foods are fortified with it.  Almost all of the milk sold in the U.S. is fortified with Vitamin D, as are many cereals, juices and yogurts. 

This time of year in Columbus ain't exactly the most Vitamin D friendly environment - the sun seems to head south for the winter - so it's not unusual for people around here to have a low Vitamin D level.  But what does that really mean?  How low is too low?  And does having a low Vitamin D level increase your risk for depression, high blood pressure, the flu?  We don't know for sure.  There's even a lot of debate going on right now about whether or not the current cut off for a "normal" Vitamin D level is too high and that a lot of people are being told they have a deficiency when they really don't. 

That being said, people build up the majority of their bone density during their twenties so it wouldn't hurt to take a daily adult multi-vitamin containing around 600 IU of Vitamin D to help prevent osteoporosis later in life.  It's also a good idea to get some regular sunlight exposure whenever you can; even if it's cold, it'll turn on your skin's Vitamin D factory.  But don't overdo it - taking too much (over 4000 IU) can cause damage to the heart, blood vessels and kidneys.  And excessive uv radiation exposure can damage your skin and put you at risk for really bad things.   

The National Institutes of Health has a great site about Vitamin D supplements, and the Mayo Clinic also provides a lot of good information.  And of course, you can always make an appointment to see us if you're worried about your Vitamin D level.   

John A. Vaughn, MD
Student Health Services
The Ohio State University


  • Friday, December 07, 2012 11:31:50 AM Posted by: Karen M I was just tested as having LOW vitamin D levels. My doctor suggested that I take 5000 units daily. Your article states "+4000 units is bad.; now I'm concerned. Off to do more studying on this subject.
  • Tuesday, December 11, 2012 8:46:42 AM Posted by: Dr. Vaughn Great question Karen. The amount you take depends on many things: how low your level is, how well you absorb it, how you time your doses and other risk factors. We were referring to people who just take it as a vitamin supplement. For most people, even those who have low Vitamin D levels, taking 600-800 units per day is sufficient, but there are many instances where people need more, so keep talking to your doc about it - no one knows you better (medically speaking) than s/he does.
  • Tuesday, December 18, 2012 2:59:54 PM Posted by: Mike H I'm not a doctor, but I have been doing a lot of research into Vitamin D studies. The consensus is you want 25OH levels in the 50 - 80 ng/ml range. These studies haven't permeated into recommendations, but there have been no indication of toxicity near those levels. For most people, taking 4000IU - 5000IU per day is required to sustain those levels. I am personally trying to keep mine at 65 ng/ml since that is the middle of all recommendations, including the "normal" range (32-100 ng/ml) that you will find printed on the blood test.
  • Thursday, December 20, 2012 3:36:55 PM Posted by: Dr. Vaughn Thanks for your comment Mike. The Institute of Medicine has defined the "tolerable upper intake level" for vitamin D as 4000 IU a day for healthy adults and children 9 to 18 years. But like we said, everyone is different and if someone is Vitamin D deficient they may need more. Vitamin D intoxication has been documented in adults taking more than 60,000 IU per day which would require a pretty ridiculous amount of supplementation. When in doubt, talk to your doc and make sure you keep an eye on your levels. Thanks!

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