A new study suggests that high doses of vitamin C can rapidly kill drug-resistant strains of the bacteria that cause tuberculosis (TB).
The surprise effect has only been demonstrated with laboratory cultures, but it raises the possibility of new ways of tackling the hard-to-kill bacteria.
A team from Albert Einstein College of Medicine in New York made the finding public in a paper published online in "Nature Communications" on May 21.
In a video released by the college, the study's senior author, William Jacobs, called the result of the tests "totally unexpected."
"I was in disbelief," Jacobs said. "How could this be that vitamin C could kill tuberculosis?"
In the study, Jacobs and his colleagues said they had demonstrated that at a certain concentration, vitamin C could sterilize cultures of Mycobacterium tuberculosis bacteria within just a few weeks.
They said vitamin C had the same effect on drug-resistant strains and extensively-drug-resistant strains.
"One of the things that you would like in an ideal drug is have a drug that doesn't induce resistance," Jacobs said. "To this day we have been unsuccessful in isolating vitamin C resistant mutants, which is very surprising. That's almost like the dream drug that you would like to have that will never get resistance."
The authors of the study urged further research into the potential uses of vitamin C in TB treatment, stressing it was "inexpensive, widely available, and very safe to use."
If the results hold up in clinical trials, the study raises the possibility that vitamin C could be used alongside TB drugs to speed up treatment.
And by finding the mechanism by which vitamin C kills the bacteria, scientists could point to a promising route for the development of new TB drugs.
Catherine Vilcheze, who co-authored the study, said, "We're not saying vitamin C is the cure for TB. But we should look at trying to find ways to mimic the way it kills TB bacteria [in vitro], because it is very, very effective."
Dr. Ruth McNerney, a senior lecturer in Pathogen Biology and Diagnostics at the London School of Hygiene and Medicine, calls the study "interesting."
"We will only know when people start to try," she says when asked if it could eventually translate into an actual drug. "What [the study] certainly does do -- it points us in a new direction to perhaps look at a new area of drug discovery that we haven't been thinking about before."
Dr. Daniela Maria Cirillo, head of the Emerging Bacterial Pathogens Unit at the San Raffaele Scientific Institute in Milan, agrees.
"To extrapolate on what can be the impact [of the study] on the treatment of tuberculosis, it’s almost impossible to predict," Cirillo says. "But it is a very good news for everybody working in the field."
An airborne disease of the lungs, tuberculosis remains a leading cause of death in the world.
In 2011, there were believed to be some 12 million TB cases, about 630,000 of them of the variety that does not respond to the most potent drugs.
According to the World Health Organization, 1.4 million people died from TB that year. More than 95 percent of such deaths occur in low- and middle-income countries.