Washington: Vitamin D is not just important for building strong bones, but also plays an essential role in the body’s fight against infections such as tuberculosis, according to scientists.
People with darker skin traditionally have had a higher susceptibility to tuberculosis, and areas of Africa lead the world with the highest infection rates.
And scientists believe this may be partly due to the skin pigment melanin, which is more abundant in darker skin, that shields the body from absorbing ultraviolet rays, but also reduces vitamin D production.
The international team of researchers examined the mechanisms that govern the immune system’s ability to kill or inhibit the growth of pathogens such as M. tuberculosis, the bacteria causing tuberculosis.
The team found that T-cells, which are white blood cells that play a central role in immunity, release a protein called interferon- that triggers communication between cells and directs the infected immune cells to attack the invading tuberculosis bacteria.
However, this activation requires sufficient levels of vitamin D to be effective.
The team next tested serum taken from blood samples in healthy humans with and without sufficient vitamin D and found that the immune response was not triggered in serum with lower vitamin D levels, such as those found in African Americans.
But, when adequate vitamin D was added to deficient serum, the immune response was effectively activated.
The team notes that vitamin D may help both innate and adaptive immunity, two systems that work synergistically together to fight infections.
“Our findings suggest that increasing vitamin D levels through supplementation may improve the immune response to infections such as tuberculosis,” said first study author Dr. Mario Fabri, who conducted the research at UCLA.
The study has been published online Oct 12 in the peer-reviewed journal, Science Translational Medicine.