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In a study of middle-aged type II diabetics, subjects received either a placebo or 1,000 IU of vitamin D daily.34 After one year, supplemented patients had a decrease in their measure of arterial stiffness known as the central aortic augmentation index. There was no improvement in the placebo group.34

Another study examined adults with elevated blood pressure who were vitamin D deficient. After taking 4,000 IU of oral vitamin D3 daily for 6 months, they experienced a 12.3% reduction in arterial stiffness (as measured by augmentation index). No changes were shown in a control group receiving 400 IU/day (the standard “recommended” dose).31

A Danish study conducted in winter months demonstrated that 3,000 IU of vitamin D3 reduced both systolic (top number) and diastolic (bottom number) blood pressure in subjects who were vitamin D insufficient (<32 ng/mL).30

Numerous subsequent studies have confirmed vitamin D’s arterial stiffness-reducing effects in both healthy and high-risk populations.27,29,35

The preponderance of evidence shows vitamin D to be a critical factor in preventing the many disorders associated with arterial stiffening—especially those involving standard risk factors such as hypertension.