David C. Sane, MD, FACP
Professor and Chief of Cardiology
Virginia Tech Carilion School of Medicine

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This video is from a presentation at one of our Diagnosis and Treatment of Vitamin D Deficiency Seminars. The presentation is geared toward the audience of primarily doctors and health care professionals, but is full of useful information for anyone who is up for an education!

How the heart processes vitamin D

Early in the presentation is an explanation of the vitamin D receptors (VDR) in the heart, blood vessels, and heart tissues. Over 200 genes and 30 tissues in the heart and blood vessels are affected by activated vitamin D. VDRs are also in immune cells - which help to reduce inflammation in the heart. Sane explains that there are both rapid and genomic responses to vitamin D exposure, varying in time from seconds to minutes for the rapid response, to hours to days for the genomic response.

One very important function of vitamin D is to shut down the production of renin - ultimately lowering blood pressure, which is a main factor in heart disease.

Many studies of vitamin D and the heart

Sane cites animal studies which have been done to understand the VDRs and what happens with exposure to vitamin D - such as reduced calcification, arterial stiffness, and inflammation. He also reviews studies with people, concluding that there are many studies which show higher vitamin D levels reduce the risk of CVD. Two of the studies summarized in this presentation are featured below as our papers of the week. In an analysis of the Health Professionals Follow-Up Study, researchers showed that if a man has a vitamin D level > 30 ng/ml, then he will have about half the risk of a myocardial infarction (heart attack) (starting at 25:40). He discusses the Framingham Offspring Cohort study and summarizes that there was an association between cardiac events and vitamin D status. (starting at 24:20).

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A Prospective Study of 25-Hydroxy-Vitamin D and Risk of Myocardial Infarction in Men
Edward Giovannucci, MD, et al.
Professor of Nutrition and Epidemiology
Harvard School of Public Health

This study explored the relationship of vitamin D deficiency and myocardial infarction (MI) in men. There have been observations that CVD death is higher at higher latitudes and increases during winter months, both of which are consistent with similar patterns in vitamin D deficiency. Vitamin D is also known to influence vascular smooth cell proliferation, inflammation, and blood pressure - all risk factors for CVD. 

This study made use of data from the Health Professionals Follow-Up Study (HPFS), which enlisted over 50,000 male health care professionals in a voluntary study to evaluate diet and chronic disease. The study administers a health and disease questionnaire every 2 years; a food frequency questionnaire every 4 years; and asked for a blood sample once. From 18,225 participants who provided blood samples, those with a history of CVD were excluded. 

At the time of analysis, 454 men had developed nonfatal myocardial infarction (MI) or fatal CVD. For comparison, two controls - participants with a blood sample who were alive and did not have a history of CVD at the time of case ascertainment - were matched for each case. The full paper is available online and includes many charts which explain the characteristics of the cohort - looking at a myriad of health markers such as age, BMI, smoking, cholesterol, etc. After crunching the numbers many different ways they determined that a vitamin D level of 30 ng/ml or higher would lower the risk of MI by about half. They saw similar results with fatal coronary heart disease (CHD) - but had too few subjects to definitively conclude the same about CHD. Only 23% of the HPFS cohort had a vitamin D level over 30 ng/ml, so they could not assess whether a higher vitamin D level would have even more benefit. 

 
The paper also reviewed other vitamin D studies with respect to CVD - with both positive and negative results - and explained why their hypothesis was disproved (didn't provide enough vitamin D to change serum level, one gave 100,000 IU once every 4 months). We encourage you to look at our Careful Eye page to see how to best understand results of RCT studies on nutrients.

Note: discussion of this paper at 25:40 of video

If you are reading this newsletter, you probably already believe in the benefits of vitamin D. But it is always interesting to study vitamin D's effects with respect to a certain condition. Today we reviewed heart disease. 

It would be helpful if every one of you took the time to think of two people that either have heart disease, or are heading that way - and forward them this newsletter. A short pre-amble could be:

Dear friend,

Sincerely,

Your Name

Thank you for helping to spread the word - just two emails!