10:20am UK, Tuesday June 03, 2008

The makers of probiotic drinks believe the drinks may help lift the symptoms of hay fever.

Sneezing irritates

A new study believes the drinks can change the way the immune system responds to pollen.

Hay fever is thought to occur when the immune system responds to pollen by producing excessive amounts of an antibody known as IgE, which in turn releases histamine to flush out the spores.

This irritates the airways, making them swell and producing the symptoms of hay fever.

Researchers at the Institute of Food Research, funded by Yakult and the British Biotechnology and Science Research Council, found that a daily dose of probiotic "significantly" altered levels of antibodies associated with allergic reactions.

Twenty volunteers took part in the five-month study, with half given the probiotic and half given a placebo, although clinical symptoms were not investigated.

The scientists took blood samples before, during and after the grass pollen season.

The volunteers showed no significant differences in levels of IgE at the start of the study, but those in the probiotic group showed lower levels both during and after the peak season.

At the same time, levels of the antibody IgG, thought to play a protective role against allergic reactions, were higher.

Research leader Professor Claudio Nicoletti said: "This was a pilot study based on small numbers of patients, but we were fascinated to discover a response.

"The probiotic significantly reduced the production of molecules associated with allergy."

Dr Kamal Ivory, a senior member of the group, said: "The probiotic strain we tested changed the way the body's immune cells respond to grass pollen, restoring a more balanced immune response."

The next stage of the study will look at whether the immunological changes translate into a real reduction in the clinical symptoms.