Test Your Vitamin D Knowledge
By Dr.Joseph Mercola

Vitamin D is the most common nutritional deficiency in theUnited States, and most physicians are clueless about itsimportance. If you can answer the majority of these questionscorrectly you are doing better than the majority of physicians.
Please remember that without question the best way to optimizeyour vitamin D level is with regular exposure of large portionsof your skin to the sun. However, with Labor Day behind us it istime for most of us to consider switching our source of omega-3fats from fish oil to cod liver oil, as that will supply themissing vitamin D that many of us will start lacking due todiminishing sun exposure.
This test was developed by Dr. John Cannell. He is one of theleaders in the vitamin D education movement and has a verycomprehensive Web site dedicated to vitamin D. You can alsosubscribe to his free newsletter there.
1.Vitamin D reversesinflammatory changes associated withage-related memory impairment.
a) True b) False
True.Researchers from Ireland were the first to demonstratethat vitamin D3 acts as an anti-inflammatory agent and turnsold brains into young brains--at least as far as inflammatorycytokines are concerned.This research suggests vitamin D mayprevent, or even treat, age-related cognitive decline!
Biochem Soc Trans. 2005 Aug;33(Pt 4):573-7.
2. Your blood sugar is closely associated with your vitamin Dlevel.
a) True b) False
True.Researchers in Australia added to the growing evidencethat sun avoidance may have caused the epidemic of type 2diabetes.The Australians' findings were straightforward andpowerful. The higher yourvitamin D level, the lower your bloodglucose.
Clin Endocrinol (Oxf). 2005 Jun;62(6):738-41.
3. In July, a group from Minnesota found that 100 percentofelderly patients admitted for fragility fractures werevitamin-D deficient despite the fact that half of them were taking vitamin D supplements.
a) True b) False
True.The authors found that women taking supplemental vitamin Dhad average levels of 16.4 ng/ml while women not takingsupplements had levels of 11.9.ng/ml, both dangerously low.None of the 82 women got enough sun or took enough vitamin D toobtain a level of 40 ng/ml. These were fragility fractures, notfractures caused by unusual trauma.That is, their bones justsort of fell apart.
Curr Med Res Opin. 2005 Jul;21(7):1069-74.
4. Women with the lowest vitamin D levels had five times higherrisk for breast cancer.
a) True b) False
True.Women with 25(OH)-vitamin D blood levels less than 20ng/ml were more than five times more likely to be diagnosedwith breast cancer than were women with levels above 60 ng/ml.That is five, repeat five, timesmore likely!
Eur J Cancer. 2005 May;41(8):1164-9. Epub 2005 Apr 14.
5. Avoiding the sun doubles the risk of prostate cancer.
a) True b) False
True.Again, the risk of avoiding the sun is clear, this time inanother study with prostate cancer.However, the authors pointedout that sun exposure increases the risk of skin cancer andbelieved that proper vitamin D supplementation "may be thesafest solution to achieve an adequate vitamin D status."
Cancer Res. 2005 Jun 15;65(12):5470-9.
I also believe supplementation is the only way to go for manypeople.African Americans are simply unable to spendan adequatetime in the sun.In addition, the sun ages the skin and thatfact alone will keep many Americans out of the sun.That said, Igo into the sun whenever I can. The reason is simple: it is themost conservative thing to do. Until we know everything the sundoes--and itdoes morethan just make vitamin D--the conservativeapproach is to mimic our ancestors and the environment in whichhumans evolved, whenever we can.Therefore, it makes sense tosunbathe sensibly in the late spring, summer and early fall andtake supplements or use UVB lamps the rest of the time.
6. South Korean researchers associated vitamin D deficiencywith Parkinson's disease.
a) True b) False
True.Actually, they showed that certain genetic malformations(VDR polymorphisms) are more likely in patients withParkinson's disease, implying an association with vitamin D andParkinsonism.
J Korean Med Sci. 2005 Jun;20(3):495-8.
7. Researchers in England discovered that patients with chronicpain have phenomenally low vitamin D levels.
a) True b) False
True.The authors added to the evidence that severe vitamin Ddeficiency is associated with chronic pain.They found that 88percentof their patients with chronic pain had levels less than10 ng/ml.If they treated their patients, they did not report it.However, Swiss researchers recently treated chronic painpatients with vitamin D and reported the pain "disappeared"within one to three months in most of their patients. This isthe second open study that showed adequate doses of vitamin Ddramatically improved chronic pain.
Ann Rheum Dis. 2005 Aug;64(8):1217-9.
BMJ. 2004 Jul 17;329(7458):156-7.
Spine. 2003 Jan 15;28(2):177-9.
8. Severe vitamin D deficiency is common in TB patients.
Some English doctors don't know the difference between idealand "normal" levels.
Most American doctors don't know the difference either.
a) All are true b) All are false c) Some are true and some are false
All are true.First, the authors reviewed the impressive animalevidence that vitamin D can help treat TB.Then they reportedthat most of their immigrant TB patients had undetectablevitamin D levels.Then they reported the normal range for theirlab was between 5 to 47 ng/ml but "normal" was any levelgreater than 9 ng/ml. Finally, the researchers reported theytreated their patients with "normal daily doses" of vitamin D,without reporting how much they gave. Apparently, they gavejust enough to get patients above 9 ng/ml.
J Infect. 2005 Jun;50(5):432-7.
Keep in mind that different laboratory techniques result indifferent ranges for 25(OH)-vitamin D levels. No matter whattechnique is used, ideal levels can roughly be defined as anylevel above the median. In this case, as you will see below inDr. Heaney's article, the doctors should have treated theirpatients with 4,000 units a day.They should also have watchedfor evidence of vitamin D hypersensitivity, which can occurwhen treating tuberculosis patients for vitamin D deficiency.
We can only mourn for the poor immigrants who have to sufferfrom both TB and vitamin D deficiency.Of course, few physiciansin theUnited Statesknow the difference between the Gaussiandefinition of "normal" (average ranges for the populationtested) and the ideal definition of "normal" (levels above 32ng/ml).Getting commercial reference labs to report ideal25(OH)-vitamin D levels should be a priority of everyoneinvolved in trying to end the epidemic of vitamin D deficiency.
9. Virtually all nephrologists give renal failure patients avitamin D-like drug.
Virtually all renal failure patients are severely vitamin Ddeficient.
Some nephrologists know the difference between vitamin D andcalcitriol.
a) All are true b) All are false c) Some are true and some are false.
All are true.Finally, the truth about renal failure patients:most of them are vitamin D deficient despite taking vitamin Danalogs!Most nephrologists prescribe activated vitamin D(calcitriol) or vitamin D analogs but not vitamin D.Calcitrioland vitamin D analogs do nothing to prevent vitamin Ddeficiency. Renal failure patients need both vitamin D and acalcitriol-like drug. Moreover, 400 units a day of vitamin Dwill not correct their deficiencies.As you will see below, theyneed up to 4,000 units.
Am J Kidney Dis. 2005 Jun;45(6):1026-33.
P.S.If you think nephrologists know the difference betweenvitamin D and calcitriol, read this month's paper from somenephrologists at the University of Texas.They discuss theimportance of vitamin D in preventing and treating heartdisease.(I think adequate vitamin D nutrition may prevent morecardiovascular deaths than cancer deaths.)However, I read theTexas paper three times and still don't know if the authorsknow the difference between vitamin D and calcitriol.I hopethey know the difference between cholesterol andtestosterone.(Some cholesterol is metabolized into steroidhormones, vitamin D is a prehormone; testosterone is a steroidhormone, calcitriol is the most potent steroid hormone in thehuman body).
Kidney Int Suppl. 2005 Jun;(95):S37-42.
10. Professor Robert Heaney proved, again, that he is agentleman and a scholar.
a) True b) False
True.In the most important clinical paper published this month,Heaney gave the three best reasons why we should all maintainminimum levels of at least 32 ng/ml, the level that:
(a) Effectively suppresses PTH (b) Maximizes calcium absorptio, (c) Maximally improves glucose tolerance
Then he goes on to show that some of us, especially AfricanAmericans, will need to take 3,000 to 4,000 units every day tomaintain healthy 25(OH)-vitamin D blood levels.
J Steroid Biochem Mol Biol. 2005 Jul 15.
He then defends the Institute of Medicine's (IOM)recommendation that we only take one-tenth that amount, as thebest science that was available in 1997.I admire Dr. Heaney fortrying to cover for the IOM.The truth is that both Dr. Heaneyand Dr. Holick told the IOM that 2,000 units a day was nottoxic and would prevent both adequate treatment and meaningfulresearch.The IOM then proceeded to ignore the only two vitaminD experts on the panel.
Writing two years later, Professor Reinhold Vieth came up withdozens of studies the IOM overlooked.These studies conclusivelyshowed 2,000 units a day could not be toxic. Furthermore, Viethfound the literature published before 1997 clearly showed10,000 units a day was unlikely to be toxic.Vitamin D toxicityprobably starts around 20,000 units a day, and then only iftaken for months or even years.
Am J Clin Nutr. 1999 May;69(5):842-56.
Related Articles: Vitamin D Deficiency is Major Health RiskTheSecret Benefits of Vitamin D Vitamin D Lowers Inflammation
About the Author: Dr. Mercola is the founder of Mercola.com,one of the world's most visited and trusted health websites,and publisher of the free Mercola.com e-newsletter -- the #1dietary health and wellness newsletter on the Web with over500,000 subscribers. Dr. Mercola, a physician for over twodecades, is also a New York Times bestselling author whoselatest book, "Dr. Mercola's Total Health Program," presents hisentire renowned dietary health program and has sold over 150,000copies. He is routinely interviewed by the media for his expertinsights, including CNN and ABC World News Tonight. His passionis to change the fatally flawed conventional medical system toone focused on real prevention and cure.
Source: http://www.isnare.com