New research could pave the way for the treatment of vaginal yeast infections by shedding new light on how microbes in the body absorb zinc.
Also called thrush, the infection is caused by a yeast called Candida.
There are a number of species of Candida but the one that causes most yeast infections is Candida albicans.
The new research has found that the trace mineral zinc could play a surprising role in tackling the infection.
Like people, Candida albicans needs zinc in its diet and this yeast produces a molecule which tries to scavenge zinc as a food source.
Researchers found that the molecule triggers an inflammatory response, which they believe is responsible for many cases of thrush.
According to the findings, a zinc-based gel can ease symptoms caused by the immune response and can prevent reinfections.
Researchers suggest the treatment’s simplicity and ease-of-use indicate it could be quickly translated into a badly needed therapy for the infections, which affect three quarters of women of childbearing age.
Wellcome Trust senior fellow Dr Duncan Wilson, of the University of Exeter’s MRC Centre for Medical Mycology, led the research.
He said: “Recurring thrush can be deeply distressing and problematic, and we urgently need new treatments.
“Our new finding on zinc is very exciting because it suggests that simple provision of zinc could block the production of the inflammatory Pra1 molecule but we’re not in the position to make treatment recommendations at this stage.
“We need larger scale trials to confirm the effect. Please don’t apply any products that are not designed for the genital area, as zinc can be toxic at high concentrations and it could be extremely unsafe.”
Around three quarters of women develop the infections at least once in their lifetime, and according to experts some 140 million women across the world suffer from recurrent infections which potentially impact their quality of life.
Existing anti-fungal treatments are not always effective and resistance against them is developing.
In laboratory experiments, the team found that manipulating genes so that Candida albicans does not produce the Pra1 molecule prevented inflammation.
The study went on to find that applying relatively low levels of zinc in mice blocked production of the molecule and prevented inflammation.
This is important because it is inflammation that causes the burning and itching symptoms of thrush.
The research team also recruited women who had been experiencing vaginal infections at least once every three months.
The women applied vaginal moisturising cream Juvia – available in the EU but not currently in the UK – which contains a small amount of zinc, nightly for two weeks, and then twice a week.
Of six women who completed the study and had thrush, five of them did not experience reinfection over the three-month study.
Dr Wilson said: “These findings are very encouraging although the number of participants is small.
“We are now carrying out a larger clinical trial to confirm that zinc treatments are effective.
“In the longer term, we hope this could be a promising strategy for a condition which could evolve resistance to treatment.”
Funded by Wellcome and led by the University of Exeter’s MRC Centre for Medical Mycology, the findings are published in Science Translational Medicine.