January 25, 2018
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High doses of vitamin D reduce arterial stiffness in African-Americans

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Yanbin Dong
Yanbin Dong

Young, overweight and vitamin-deficient African-Americans who took high doses of vitamin D daily reduced their arterial stiffness within 4 months, according to research recently published in PLOS One.

“African-Americans are not as likely to receive sufficient vitamin D from the sunshine and natural light as their white counterparts,” Yanbin Dong, MD, PhD, geneticist and cardiologist at the Georgia Prevention Institute at the Medical College of Georgia at Augusta University, told Healio Family Medicine. “In addition, obesity can contribute to vitamin D deficiency. African-Americans, in general, are also at higher risk for cardiovascular outcomes. All of this taken together necessitates we look at this topic.”

Researchers randomly assigned 70 overweight African-Americans aged 13 to 45 years, with BMIs of 25 kg/m² or greater for adults and 85th percentile or greater in teenagers, and with serum 25-hydroxyvitamin D levels of 20 ng/mL or less to receive oral vitamin D3 supplementation of approximately 600 IU a day (n = 17); 2,000 IU (n = 18); 4,000 a day (n = 18); or a placebo (n = 17) for 16 weeks. People taking dietary supplements or medications, who had any medical condition that could affect nutritional status or metabolism, or who were pregnant were not considered for the study.

Dong and colleagues found that the mean changes in carotid-radial pulse wave velocity across the four treatment groups were 0.24 m/s (95% CI, –0.45 to 0.92 m/s) for placebo, 0.09 m/s (95% CI, –0.54 to 0.73 m/s) for the 600 IU a day group, –0.57 m/s (95% CI, –1.2 to 0.07 m/s) for the 2,000 IU a day group, and –0.61 m/s (95% CI; –1.25 to 0.02 m/s) for the 4,000 IU a day group.

In addition, findings were nearly identical in the mean changes in the carotid-femoral pulse wave velocity across the four treatment groups: 0.13 m/s (95% CI, –0.24 to 0.51 m/s) for placebo, 0.02 m/s (95% CI, –0.34 to 0.38 m/s) for 600 IU a day group, –0.11 m/s (95% CI, –0.5 to 0.27 m/s) for the 2,000 IU a day group, and –0.7 m/s (95% CI, –1.07 to –0.32 m/s) for the 4,000 IU a day group.

“This is one of the first studies to look at vitamin D as it relates to cardiovascular health,” Dong said in the interview. “Primary care physicians who have African-American patients who are vitamin D deficient should encourage these patients to take vitamin D supplements of about 2,000 IUs daily.”

He cautioned that healthy patients with sufficient levels of vitamin D do not need to overdo their vitamin D intake, because the nutrient is not a “magic bullet” that will cure everything. – by Janel Miller

Disclosure: The authors report no relevant financial disclosures.