Friday, March 9, 2018

Could Vitamin D Lower Cardiovascular Death Risk?

People who have cardiovascular disease can reduce their risk of death by almost a third simply by maintaining normal vitamin D levels. This is the finding of a new study recently published in The Journal of Clinical Endocrinology & Metabolism.

Cardiovascular disease (CVD) is the number 1 killer in the United States. Heart disease alone is responsible for around 610,000 deaths in the country every year. Previous research suggests that vitamin D status may play an important role in cardiovascular health. A study in 2016, for example, associated low vitamin D levels with greater risk of stroke, heart failure, heart attack, and cardiovascular death.

The new study – led by Prof. Jutta Dierkes, of the Department of Clinical Medicine at the University of Bergen in Norway – further investigated the role that vitamin D levels play in the risk of death from CVD.

Prof. Dierkes and colleagues analyzed the blood samples of 4,114 adults who had suspected angina pectoris, which is chest pain as a result of coronary heart disease. Subjects were an average age of 62 at study baseline, and they were followed-up for an average of 12 years.

The team assessed the subjects’ blood samples for levels of 25-hydroxyvitamin D, or 25(OH)D, which is the primary circulating form of vitamin D. During follow-up, there were a total of 895 deaths. Of these, 407 were related to CVD.

According the National Institutes of Health (NIH), as 25(OH)D level of 50-125 nanomoles per liter (nmol/l) is “generally considered adequate for bone and overall health in healthy individuals.”

In the study, the researchers found that the optimal 25(OH)D blood concentrations for mortality risk were 42-100 nmol/l. Concentrations lower than 42 nmol/l and higher than 100 nmol/l were associated with a greater risk of death from DVD. “We discovered,” says Prof. Dierkes, “that the right amount of vitamin D reduces the risk of death substantially. However, too much or too little increase the risk.”

Based on these results, Prof. Dierkes recommends that all people with CVD have their vitamin D levels measured and monitored. If levels are below normal, vitamin D supplementation might be required.

My Take:
The medical norms for 25(OH)D are 30-100 nmol/l but I prefer my patients have a minimum of 40 nmol/l. High levels (> 100) are rare but can occur with intestinal parasites or excess supplementation. The nutrition board allows me to recommend 4,000 IU of vitamin D3 (the precursor to 25(OH)D) daily with no laboratory tests to document the deficiency. However, if I exceed that recommendation (and often, I do) then lab tests must be performed to monitor vitamin D levels in the blood.

Vitamin D3 in food, as a supplement, or manufactured when sunlight converts cholesterol to D3 in the skin travels to the liver to be converted to 25(OH)D. It then circulates as the stable inactive form of vitamin D. Conversion to the active form, 1,25(OH)D takes place primarily in the kidneys but every cell in the human body can make the conversion for its own use. The active form varies constantly and dramatically in the blood stream and although sometimes measured, the test has little value.

The Bottom Line:
Whether you have CVD or not, I recommend you have your vitamin D levels measured with a blood test every year as a minimum. Even in S. Florida, deficiency is widespread.

Source: National Institutes of Health March 3, 2018

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