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Information on the latest vitamin D news and research.

Find out more information on deficiency, supplementation, sun exposure, and how vitamin D relates to your health.

Response to CRP and vitamin D association finding

In a paper critical of higher levels of vitamin D for allegedly increasing a marker of inflammation, c-reactive protein (CRP), Drs. Muhammad Amer and Rehan Qayyum of the Johns Hopkins School of Medicine, began their paper by saying:

“The cardiovascular protection offered by vitamin D and its analogues is probably mediated by modulation of inflammatory cytokines.”

Amer M, Qayyum R. Relation Between Serum 25-Hydroxyvitamin D and C-Reactive Protein in Asymptomatic Adults (From the Continuous National Health and Nutrition Examination Survey 2001 to 2006). Am J Cardiol. 2011 Oct 12.

If you will notice, both physicians know that vitamin D offers “cardiovascular protection.” However, they are concerned 25(OH)D levels higher than 20 ng/ml will increase inflammation as measured by CRP and thus worsen cardiovascular protection. CRP is a protein in the blood which tends to rise in response to inflammation or injury. Its physiologic role is to take part in the “complement system.”

The authors arrived at this conclusion by adjusting their data for up to 9 variables and finding that a 25(OH)D of 20 ng/ml is associated with a CRP (range 0-5) of approximately 1.7 while a 25(OH)D of 50 ng/ml is associated with a CRP of 1.9. Their raw findings contradict their adjusted data in that the raw data showed what we have known for some time and that is that in the lower ranges of 25(OH)D, vitamin D reduces CRP. As with most biomarkers of vitamin D, the big improvement is in people who get their 25(OH)D up  from 5 ng/ml up to 20 ng/ml. We know that in most cases, the biggest bang for the buck is in treating severe deficiency in people with such low levels.

So if you have natural levels of vitamin D, say a 25(OH)D of 50 ng/ml, and you want to decrease your CRP by 0.2, then stop your vitamin D and stay out of the sun, get your levels to 20 ng/ml, and see if all the corrections and adjustments the doctors performed were correct. I certainly am not going to do such a silly thing.

Dozens of studies now exist showing supplemental vitamin D3 reduces mortality rates, in part due to its cardiovascular protection. The majority of these studies show that improvement in mortality continues through 30 ng/ml and even up to 40 ng/ml. Not enough people have levels of 50 ng/ml for scientists to see if such levels offer further protection. However, cardiovascular disease is rare in native peoples around the equator where vitamin D levels of 50 ng/ml are not uncommon.

The takeaway message from this paper is that scientists will need to recalculate lots of different “normals,” using vitamin D sufficient subjects. It’s not just that normal CRP may be a bit higher in vitamin D sufficient people, their red blood count and the protein albumin may be a bit lower, for example. The point is that pathologists and epidemiologists will need to redo much of their work. We don’t know the normal range of CRP in 65-year-old men; we know the range of CRP in 65-year-old vitamin D deficient men. Likewise, we don’t know the incidence of heart disease in 65-year-old men; we know the incidence of heart disease in vitamin D deficient 65 year-old men. We have lots of work to do.

About John Cannell, MD

Dr. John Cannell is founder of the Vitamin D Council. He has written many peer-reviewed papers on vitamin D and speaks frequently across the United States on the subject. Dr. Cannell holds an M.D. and has served the medical field as a general practitioner, emergency physician, and psychiatrist.

8 Responses to Response to CRP and vitamin D association finding

  1. Brant Cebulla says:

    A few good articles on CRP in the New York Times, thanks to Jim Larsen:
    http://www.nytimes.com/2009/07/01/health/01heart.html

    “Different people produce different amounts of CRP, and the amount a person produces is determined by tiny inherited changes in the CRP gene. So in a population, there are people who just happen to produce more CRP throughout their lives and others who just happen to produce less. If CRP causes heart disease, those who make more would have more heart disease. That, however, is not what the study found.

    ‘There was no association between CRP genes and heart disease rates,’ Dr. Elliott said.

    The association between CRP and heart disease must be reflecting something else. For example, if CRP levels go up when heart disease begins, because of inflammation in arteries, CRP levels would be higher in people with incipient heart disease. But CRP itself would be playing no role in heart disease risk; it was just marker of inflammation.”

  2. Frederica Huxley says:

    As I was reading this much needed rebuttal to the mainstream news, the following came into my e-mail:
    http://www.healthcanal.com/public-health-safety/25465-Testing-vitamin-levels-most-patients-costly-confusing-and-without-credibility.html?utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+healthnewshc%2FOxfp+%28Health+News+from+HealthCanal.com%29
    The mind boggles – especially with regards to your recent

    excellent article on vitamin D deficiency in the higher latitudes!

  3. PeterVermont says:

    I found your point about the raw data confusing. You state “The authors arrived at this conclusion by adjusting their data for up to 9 variables and finding that a 25(OH)D of 20 ng/ml is associated with a CRP (range 0-5) of approximately 1.7 while a 25(OH)D of 50 ng/ml is associated with a CRP of 1.9. Their raw findings contradict their adjusted data in that the raw data showed what we have known for some time and that is that in the lower ranges of 25(OH)D, vitamin D reduces CRP. ” as if that refutes the article but what does the raw/unadjusted data show about the relationship at HIGHER ranges of 25(OH)D?

  4. DaveN says:

    One can not but agree that there indeed is a lot of work to be done!
    On a personal note, my year end blood test results showed a “D” level of 52, along with a crp of 0.1. (I’m a 68 year old athlete)

  5. In addition to Dr. Cannell’s points about the problems with this study, it should be noted that practically all the people in this study had low vitamin D levels. (less than or over 21 ng, most of the over 21 ng were probably less than 32 ng. At these low levels, it is possible that dairy intake increases 25-hydroxyvitamin D levels within the range of 21 to 30 ng. Diet affects c-reactive protein, and it may very well be the higher fat diets of these people, although raising the D level slightly, raises c-reactive protein the very small amount.

  6. Dan says:

    Dr. Cannell should contact ConsumerLabs who test supplements. CL just added this study to its Vitamin D page without noting any details of the study. This study needs more vetting in public!

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