Probiotics may offer hay fever hope

In the first human study of its kind, scientists at the Institute of Food Research (IFR) randomly assigned 10 people with hay fever (seasonal allergic rhinitis) to receive daily probiotic milk drinks or placebo.

Hayfever is an allergic reaction to pollen or fungal spores, most commonly grass pollen.

The immune system mistakes the spores for harmful invaders and white blood cells - T-helper type 2 (Th2) lymphocytes - produce protein-like cytokines, such as interleukin-4 (IL-4), IL-5 and IL-6, which in turn promote the synthesis of the immune chemicals immunoglobulins (Ig) to bind to the pollen and fight them off.

However, supplementation with the probiotic led to reduced production of IL-5 and IL-6, as well as decreased in the production of IgE, according to findings published in the journal Clinical and Experimental Allergy .

Immunoglobulin E (IgE) is the predominant antibody associated with an allergic response.

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

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

Consumers are increasingly aware of the health benefits associated with probiotics, including improved intestinal health and immune system stimulation.

Indeed, probiotics remains a major growth market.

The European sector is set to more than triple in value over the next few years, according to Frost & Sullivan, to reach $137.9 million (€118.5m) in 2010.

Pilot study Nicoletti and co-workers recruited the hay fever sufferers aged between 18 and 45 and randomly assigned them to receive a daily milk drink with or without Lactobacillus casei Shirota.

The subjects did not normally consume fermented dairy products, were not smokers, were not asthmatic, and were unlikely to holiday abroad during the five-month study.

Grass pollen samples were collected before, during and after the peak season for hay fever, and blood samples were taken to relate these to levels of grass pollen-specific IgE and IgG, and cytokines.

The probiotic-supplemented volunteers had significantly reduced levels of IL-5 and IL-6, wrote the researchers, compared to the controls.

Moreover, IgE levels were significantly reduced.

On the other hand, IgG increased slightly in the probiotic-supplemented group.

IgG is thought to play a protective role against allergic reactions.

"The main finding of this paper is that oral administration of live LcS modifies allergen-specific responses in AR.

Selected strains of lactic acid bacteria have already been shown to influence aspects of immune function, but most of these studies have been performed in experimental mice," wrote lead author Kamal Ivory.

"There are a few documented human studies that use probiotics for therapeutic intervention, such as L. casei to reduce the severity of pathological processes like diarrhoea.

However, its capacity to influence immune function is not as clearly documented.

Probiotics hold much promise as a functional food and well-controlled human studies could clarify the influence probiotics may have, particularly in common systemic inflammatory disorders such as SAR.

Although several studies show beneficial effects of probiotics in the prevention of atopic eczema, this is the first study to support their use in another allergic disease," added Ivory and co-workers.

The results were described as "really interesting" by Dr Linda Thomas, head of science at Yakult UK, who provided the drinks and some of the funding.

"We are delighted that independent scientists found evidence of this biological activity.

The project was part of ongoing research into the benefits of our probiotic strain," she added.

The IFR scientists state they intend to continue the research with a test of whether the immunological changes translate into a real reduction in the clinical symptoms of hay fever.

They also intend to study underlying mechanisms.

The pilot study was sponsored by Yakult Honsha of Japan and the British Biotechnology and Science Research Council (BBSRC).

Source: Clinical and Experimental Allergy Published online ahead of print 28 May 2008, OnlineEarly Articles, doi: 10.1111/j.1365-2222.2008.03025.x "Oral delivery of Lactobacillus casei Shirota modifies allergen-induced immune responses in allergic rhinitis" Authors: Kamal Ivory, S.J. Chambers, C. Pin, E. Prieto, J.L. Arques, C. Nicoletti