In part one of this series, Dr. Frank addresses the epidemic of vitamin D deficiency: 30 to 100 percent of Americans don’t get enough of this crucial hormone. This deficiency can play a role in almost every major disease including 17 kinds of cancer, Parkinson’s and Alzheimer’s. This article answers questions about testing levels of vitamin D. Stay tuned for the third and final part of this series, which addresses the best ways to increase your level of vitamin D.

What are the symptoms of vitamin D deficiency?

There is no clear pattern of symptoms. In fact many people remain asymptomatic despite low levels. But here are the most common symptoms:

Fatigue
General muscle pain and weakness
Muscle cramps
Joint pain
Chronic pain
Weight gain
High blood pressure
Restless sleep
Poor concentration
Headaches
Bladder problems
Constipation or diarrhea

What blood test should I have to check my vitamin D levels?

The only blood test that can diagnose vitamin D deficiency is a 25-hydroxy-vitamin D (25 OH vitamin D). Unfortunately, some doctors are still ordering the wrong test, 1,25-dihydroxy-vitamin D. In fact, a common cause of high 1,25-dihydroxy-vitamin D is a low 25(OH)D or vitamin D deficiency. So when doctors see the 1,25-dihydroxy-vitamin D is normal or high and tell their patients that they are okay, they are often vitamin D deficient.

Your doctor should do this test for you. Unfortunately even some of the labs, in particular Qwest, have had problems with correct results, usually giving erroneously high results.

If you don’t want to go through your doctor, the ZRT lab does a blood spot test that you can order without going through a doctor.

What is the ideal blood level of 25 hydroxy vitamin D?

The current ranges for “normal” are 20 to 55 ng/ml. These are much too low! They may be fine if want to prevent rickets or osteomalacia, but not if you want optimal health. The ideal range for optimal health is 50-80 ng/ml.

How often should I have a 25 hydroxy vitamin D blood test?

At least once a year especially at the beginning of winter. If you are supplementing, I suggest you monitor your vitamin D levels approximately every 3months until you are in the optimal range. If you are taking high doses (10,000 IU a day) your doctor must also check your calcium, phosphorous, and parathyroid hormone levels every 3 months.

My doctor prescribed Drisdol, 50,000 IU per week. What is it?

Drisdol is a prescription of 50,000 IU tablets of vitamin D2 or ergocalciferol. Ergocalciferol is not vitamin D but it is similar. D2 is not normally found in humans and most studies show it does not raise 25(OH)D levels as well as (cholecalciferol or vit D3) does. If you are vitamin D deficient, the best thing to do, is to take vitamin D3.

Stay tuned for the third and final part of this series on how to increase your level of vitamin D. Dr. Frank will answer the questions: What are food sources of vitamin D? How much vitamin D should I supplement with? What about vitamin D toxicity?