Scientist - News - 11-08-2008:

Probiotics against hay fever?
Beintema, Nienke

A recent study suggests a link between probiotics and a reduced immune response to hay fever. Some online sources are critical about the results, as the sample size was small and no reduction in symptoms was observed. Others stress that this was only a pilot study, and that the results are promising.

Hayfever (also known as seasonal allergic rhinitis) is an allergic response to pollen, usually from grass species. An estimated 10 to 20 percent of all people in Western societies suffer from some degree of hay fever. The immune system reacts to the pollen as if it were a harmful pathogen. It produces cytokines, such as interleukin-5 and -6 (IL-5 and IL-6), which in turn promote the synthesis of immunoglobulins (Ig), also known as antibodies. These are to deactivate the pathogens.
Scientists at the Institute of Food Research (IFR) published a paper in the May issue of Clinical and Experimental Allergy that reports a link between daily intake of probiotic supplements and the body’s immune reaction against hay fever. The researchers randomly assigned 20 people with hay fever to receive daily milk drinks with or without Lactobacillus casei. After five months, the probiotics-supplemented group showed significantly reduced levels of IL-5 and IL-6 compared to the control group. Moreover, IgE levels were significantly reduced – Ig being the antibody that is most associated with allergic reactions. On the other hand, the production of IgG was slightly increased. IgG is thought to play a protective role against allergic reactions.

Pilot study
A growing number of studies worldwide focus on the link between probiotics and certain allergies. The results remain largely inconclusive. There is still much scepticism. Reactions to the IFR hay fever study have been mixed as well. Criticism focuses on the small sample size, the small (though significant) changes in immune reaction parameters, and the fact that no effect was observed at the level of the hay fever symptoms.
"This was of course only a pilot study," reacts Hans van Schijndel, Science Manager at Yakult Netherlands. "The aim of this study was to see if there is any change in immune reaction. These preliminary results, in our eyes, are promising." Van Schijndel refutes the allegation that the results are hardly clinically relevant. "The results are interesting enough to justify further research, to fine-tune the therapy. Perhaps there are different doses or different strains that are more effective. The researchers in this study started their search using one probiotic strain. However, there may be many strains that are more effective. Searching for those will be the next step." Van Schijndel adds that he has no doubt that probiotics have a potential role to play in the prevention and therapy of allergies. "Perhaps not as the sole remedy, but at least as a very valuable supplement to conventional immunotherapy."

More information:
Article in Clinical and Experimental Allergy