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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.

Recent study reports vitamin D may improve endothelial function in ischemic heart disease patients

In a recent publication, researchers from Iran investigated the effects of supplemental vitamin D on female patients with ischemic heart disease:

Hashemi SM, Mokhtari SM, Sadeghi M, Foroozan R, Safari M. Effect of vitamin D therapy on endothelial function in ischemic heart disease female patients with vitamin D deficiency or insufficiency: A primary report. ARYA Atheroscler. 2015;11(1):54-9.

Cardiovascular disease (CVD) is the most common cause of death and disability worldwide. Risk factors for CVD include hypertension, diabetes and metabolic syndrome, all conditions associated with vitamin D deficiency. It is estimated that 1 billion people suffer from vitamin D insufficiency or deficiency worldwide, which may in turn contribute to CVD.

The endothelium is a thin layer of cells that lines the interior surface of blood and lymphatic vessels. It performs many critical functions, including maintaining a balance between vasoconstriction and vasodilation to control blood pressure. When this function is disrupted endothelial dysfunction (ED) is said to occur, and ED is considered a major contributor to the development of CVD.

Previous research found that vitamin D supplementation reduced ED in both healthy people and people with diabetes. The authors of this study wanted to see if vitamin D supplementation could reduce ED in women who have coronary artery disease (CAD), a form of CVD where the coronary arteries become damaged and inflamed from cholesterol-containing deposits.

The study recruited women who either had chronic, stable angina or who had undergone percutaneous coronary intervention, a non-surgical interventional radiological procedure used to open clogged arteries, in the last 6 months and who where either vitamin D deficient (< 20 ng/ml) or insufficient (20-30 ng/ml). A total of 40 women who met these criteria were assigned to the study. At baseline, serum 25(OH)D levels and flow-mediated dilation (FMD) were measured. FMD is a commonly-used measure of endothelial function. Participants received an injection of 300,000 IU vitamin D3 once per month for two months. Serum 25(OH)D and FMD were measured again one month after the second dose of vitamin D was administered.

A total of 30 women completed the study. Results included:

  • Mean serum 25(OHD) levels increased from 19.00 ± 6.50 ng/mL to 53.20 ± 17.50 ng/ml post intervention.
  • Brachial artery diameter did not change significantly after the intervention (P > 0.999).
  • Brachial artery diameter after ischemia increased significantly, statistically but not clinically, after the intervention (P < 0.001).
  • FMD was significantly increased post intervention (P < 0.001).

Limitations of the study included the small sample size and the uncontrolled study design. Still, the results are encouraging. The authors concluded,

“According to these findings and the fact that vitamin D supplements are available and are inexpensive, vitamin D may be useful for prevention of more cardiovascular events in IHD patients especially in vitamin D deficient subjects.”

Sun exposure would likely provide even greater benefits for these patients as UVA radiation stimulates the release of nitric oxide, a potent vasodilator. The Vitamin D Council has previously blogged on this topic here:

https://www.vitamindcouncil.org/blog/a-look-at-how-sun-exposure-might-lower-blood-pressure/

Safe sun exposure where possible, and vitamin D supplements if not, are likely to improve heart health in numerous ways and should be encouraged in CVD patients.

  About: Rebecca Oshiro

Rebecca has a master of science degree in nutrition from Bastyr University where she conducted a university-funded study on vitamin D and athletic performance. She has a certificate in applied behavior analysis from the Florida Institute of Technology, and her passion is using behavioral technologies to assist others in making meaningful changes in their lives.