Vitamin D Heart Controversy

January 13, 2012 Written by JP       [Font too small?]

A recent publication in the American Journal of Cardiology called into question the safety of high dose Vitamin D supplementation. In the paper, researchers from Johns Hopkins University School of Medicine investigated a proposed link between Vitamin D levels and an inflammatory protein (CRP) which is considered a risk factor for heart disease. Their conclusions report that levels of D below 21 ng/ml are associated with higher CRP or C-reactive protein. This determination came as no surprise. However, participants with Vitamin D concentrations significantly above 21 ng/ml also demonstrated elevated or undesirable CRP readings. The lead author of the piece, Dr. Muhammad Amer, stated that “Clearly vitamin D is important for your heart health, especially if you have low blood levels of vitamin D. It reduces cardiovascular inflammation and atherosclerosis, and may reduce mortality, but it appears that at some point it can be too much of a good thing.”

Regular readers of this site know that I frequently recommend Vitamin D testing and supplementation in order to reach 25(OH)D levels well in excess of 21 ng/ml. So, you may be wondering if this current controversy alters my point of view of Vitamin D therapy. The short answer is “no”. I’m not being stubborn, just basing my opinion on the best possible evidence.

In the past several months, at least four intervention studies have been carried out evaluating the impact of Vitamin D supplementation on systemic inflammation. Before I describe the results of these trials, please note that intervention trials possess greater scientific validity than population studies. In an intervention setting, direct measures of cause and effect are the primary end points. Population studies tend to rely on observation and uncontrolled data. It is for this reason that intervention trials are often called for to dispute or verify data initially presented in population studies. The Johns Hopkins’ piece is based on population data.

The latest evidence pertaining to Vitamin D supplementation and CRP levels indicates that Vitamin D lowers CRP in certain disease states such as in patients with colorectal cancer and kidney disease. On the other hand, D supplementation may not have much of an impact on relatively healthy adults of varying ages and weight. Please keep in mind that in none of these scenarios did Vitamin D therapy lead to higher CRP levels or other markers of systemic inflammation. All four of the previously mentioned trials have an interventional study design.

In closing, I want to share some underreported, but highly encouraging news about Vitamin D and cardiovascular health. Two current observational studies note that low levels of Vitamin D are correlated with a higher risk of all-cause mortality and heart attack incidence. In the mortality paper, the authors recommend Vitamin D levels of between 30 to 35 ng/ml – significantly higher than the Johns Hopkins’ publication. In addition, three intervention trials from late 2011 determined that Vitamin D supplementation is capable of improving blood pressure control, insulin sensitivity and lipid levels in at-risk populations including diabetics, hypertensives and seniors. All of this research and more points to a valuable role for Vitamin D in the promotion of heart health.

To learn more about the studies referenced in today’s column, please click on the following links:

Study 1 – Relation Between Serum 25-Hydroxyvitamin D and C-Reactive (link)

Study 2 - Effects of Supplemental Vitamin D and Calcium on Biomarkers of (link)

Study 3 – Impact of Cholecalciferol Treatment on Biomarkers of Inflammation(link)

Study 4 - Vitamin D Supplementation During Exercise Training Does Not Alter (link)

Study 5 - Maintenance of Wintertime Vitamin D Status with Cholecalciferol (link)

Study 6 - Association of 25-hydroxyvitamin D Deficiency with NT-Pro BNP Levels (link)

Study 7 - Vitamin D Deficiency and Mortality Risk in the General Population (link)

Study 8 - Regular Consumption of Vitamin D-Fortified Yogurt Drink (Doogh) (link)

Study 9 - Effect of Vitamin D on Insulin Sensitivity in Elderly Patients with (link)

Study 10 - Role of Vitamin D Supplementation in Hypertension (link)

High Blood Sugar/Insulin Resistance Promotes Arterial Stiffness

Source: Cardiovasc Diabetol. 2011 Apr 15;10:30. (link)

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Posted in Bone and Joint Health, Heart Health, Nutritional Supplements

4 Comments to “Vitamin D Heart Controversy”

  1. kristi Says:

    Interesting article. Have CRP/Vitamin D studies been done in people who regularly get plenty of sunshine – I’m thinking of those living closer to the equator?

  2. JP Says:

    Hi Kristi.

    There doesn’t appear to be much data on the topic of sun exposure/Vitamin D levels and CRP. Here are a few preliminary studies that examined this topic:

    http://www.journal-inflammation.com/content/5/1/10

    http://onlinelibrary.wiley.com/doi/10.1111/j.1751-1097.2005.tb00240.x/abstract

    Be well!

    JP

  3. Ted Hutchinson Says:

    Vitamin D Council’s response to same paper
    I would point to the fact that other researchers looking at the same NHANES data have produced these results.
    Serum 25-hydroxyvitamin D levels and all-cause and cardiovascular disease mortality among US adults with hypertension: the NHANES linked mortality study.Concentrations of 25(OH)D were inversely associated with all-cause and CVD mortality among adults with hypertension in the US. Enhancing vitamin D intake may contribute to a lower risk for premature death.

    another study looking at this same NHANES data set
    Association between vitamin D and diabetic neuropathy in a nationally representative sample: results from 2001-2004 NHANES.
    Conclusions  Vitamin D insufficiency is associated with self-reported peripheral neuropathy symptoms even after adjusting for demographic factors, obesity, co-morbidities, use of medications for neuropathy and diabetes duration and control.

    Vitamin D and Racial Disparity in Albuminuria: NHANES 2001–2006
    Conclusion
    Suboptimal vitamin D status may contribute to racial disparity in albuminuria. Randomized controlled trials are needed to determine whether supplementation with vitamin analogues reduces risk for albuminuria or reduce racial disparity in this outcome.

    So all those opting for premature death or neuropathy should definitely keep their 25(OH)D levels 21 ng/mL.
    Those who prefer to live longer will try to keep 25(OH)D nearer the level naked human bodies living outdoors naturally attain and maintain and at which human milk is a complete food for human babies.

  4. JP Says:

    Thank you, Ted. The thoughtful information contained in the Vitamin D Council blog and your additional comments are much appreciated!

    Be well!

    JP

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