A large majority of Americans are vitamin D deficient, but one group is particularly prone to insufficiency. Dark skin absorbs less sunlight, and the body needs sunlight to produce vitamin D. Thus, African Americans are at a greater risk of vitamin D deficiency than other parts of the population. From the Medical College of Georgia at Augusta University, scientists conduct a first-of-its-kind study with vitamin D deficient African Americans, looking at the benefits of supplements.
In accordance with an increased risk of vitamin D deficiency, African Americans also have higher rates of heart disease and death. Scientists are not completely sure what the connection is between vitamin D and heart health, but they know it has something to do with blood vessel health. The current study focuses on arterial stiffness, a condition that promotes the development of heart disease and increases the risk of death. Being overweight or obese only makes matters worse, as fat - for unknown reasons - often hoards vitamin D.
The new study, a robust double-blind, randomized trial, recruited 70 African Americans between the ages of 13 and 45 with varying levels of arterial stiffness. Researchers conducted a comparison of arterial stiffness levels at the beginning of the study to four months of vitamin D supplementation of varying levels.
They used a non-invasive technique called pulse wave velocity to calculate arterial stiffness, taking measurements from both the carotid artery and the femoral artery.
"When your arteries are more stiff, you have higher pulse wave velocity, which increases your risk of cardiometabolic disease in the future," explained first author Dr. Anas Raed.
The more vitamin D a study participant received, the more arterial stiffness improved. In the past, the Institute of Medicine has recommended just 600 international units (IUs) of vitamin D every day for most people. The group from the study receiving the highest dose of vitamin D received 4,000 IUs, and they also experienced the most improvement in arterial stiffness.
On average, the group receiving 4,000 IUs of vitamin D experienced a 10.4 percent reduction in arterial stiffness in four months. Vitamin D supplementation at this level also showed to most effectively suppress parathyroid hormone, which hinders vitamin D’s ability to promote bone health through calcium absorption.
Other than sunlight, milk, milk products like cheese and yogurt, fatty fish like mackerel and sardines, some greens like kale and collards and fortified cereals also are good sources, also vitamin D supplements
The present study was published in the journal PLOS ONE.