Taking in ample quantities of sunlight or high doses of vitamin D—a vitamin contained in sunlight—orally can help reduce arterial stiffness, which is known to cause cardiovascular diseases, a study has shown.
Scientists who gave high doses of vitamin D to 70 obese/overweight African-American teenagers continuously for four months and evaluated them for arterial stiffness before and after found that the sunshine vitamin reduced stiffness significantly.
Rigid artery walls are an independent predictor of cardiovascular-related disease and death and vitamin D deficiency appears to be a contributor, said Yanbin Dong, geneticist and cardiologist at the Georgia Prevention Institute at the Medical College of Georgia at Augusta University, who led the study which appeared in PLOS One journal on January 2.
Overweight/obese people with dark complexion are at an increased risk of vitamin D deficiency because darker skin absorbs less sunlight—the skin makes vitamin D in response to sun exposure—and fat tends to sequester vitamin D for no apparent purpose, said Dong.
Participants taking 4,000 International Units (IU)—more than six times the recommended daily dose of 600 IU for most adults and children—received the most benefit, the scientists said.
The dose, now considered the highest safe upper dose of the vitamin, reduced arterial stiffness the most and the fastest—by as much as 10.4 per cent in four months.
Two thousand IUs decreased stiffness by 2 per cent in that time frame. At 600 IUs, arterial stiffness actually increased slightly—0.1 per cent—and the placebo group experienced a 2.3 per cent increase in arterial stiffness over the time frame.
The 4,000 upper-limit dose restored healthy blood level quicker—by eight weeks—and was also better at suppressing parathyroid hormone, which works against vitamin D’s efforts to improve bone health by absorbing calcium, they reported.
T.V. Jayan
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