The study – published in the Proceedings of the National Academy of Sciences (PNAS) – is the first to investigate the effect of vitamin D on the immune responses of patients receiving treatment for an infectious disease.
Led by Dr Adrian Martineau from Queen Mary, University of London, UK, the researchers reveal findings to indicate that high doses of the sunshine vitamin can dampen down the body's inflammatory response to infection, enabling patients to recover faster, with less damage to their lungs.
"These findings are very significant. They indicate that vitamin D may have a role in accelerating resolution of inflammatory responses in tuberculosis patients,” said Martineau. “This is important, because sometimes these inflammatory responses can cause tissue damage leading to the development of cavities in the lung. If we can help these cavities to heal more quickly, then patients should be infectious for a shorter period of time, and they may also suffer less lung damage.”
The research team noted that in the past – before antibiotics became generally available – sunshine was used to treat tuberculosis, with patients often being sent to Swiss clinics to soak up the sun's healing rays. Now, for the first time the team believes they have shown how and why such ‘light therapy’ might have helped patients with TB, and could aid people with other conditions too.
"More broadly, the ability of vitamin D to dampen down inflammatory responses without compromising the actions of antibiotics raises the possibility that supplementation might also have benefits in patients receiving antimicrobial therapy for pneumonia, sepsis and other lung infections," added Martineau.
Martineau and his colleagues randomised 95 TB patients receiving standard antibiotic treatment into two groups: for the first eight weeks of their treatment, 44 received additional high dose vitamin D, while 51 received a placebo.
Levels of inflammatory markers in blood samples were taken from the patients, and researchers conducted statistical analyses to determine the effects that vitamin D had on the immune response.
"We found that a large number of these inflammatory markers fell further and faster in patients receiving vitamin D," explained Dr Anna Coussens, who worked on the study.
The team found Mycobacterium tuberculosis (the bacterium that causes TB) was cleared from patients’ faster in those who were taking vitamin D, taking an average of 23 days to become undetectable under the microscope compared to 36 days in the patients who were taking the placebo.
However, Martineau said it was probably too early to be recommending that all TB patients should take high-dose vitamin D in addition to the standard antibiotic treatment for the disease; with more research needed before recommendations could be made.
"We are hoping to do more work to evaluate the effects of higher doses and different forms of vitamin D to see if they have a more dramatic effect," he added.