"Consumption of milk kefir and soymilk kefir suppressed [immune] response and altered the intestinal microflora in our supplemented group," wrote lead author Je-Ruei Liu from the National Taiwan University.
"Milk kefir and soymilk kefir may be considered among the more promising food components in terms of preventing food allergy and enhancement of mucosal resistance to gastrointestinal pathogen infection."
Kefir, which orginates from the Caucasus region in Russia, is popular in Eastern and Central Europe but is also gaining awareness among West European consumers for its probiotic and nutraceutical properties.
The fermented milk contains a mixture of several live microorganisms and has many of the nutrients required by the body: proteins, minerals and vitamins. Its acidity and enzymes stimulate protein digestion and appetite and decreases the cholesterol content in blood, according to research. It is also thought to stimulate microphage production, improving immunity.
The study, published in the Journal of the Science of Food and Agriculture (doi: 10.1002/jsfa.2649), looked at the effects of milk kefir and soymilk kefir supplementation on mice injected with ovalbumin to produce an allergic response. Levels of the allergic-specific response Immunoglobin E, IgE, and G1 (IgG1) were measured, as well as intestinal microflora concentrations.
Fifty mice were randomly assigned to one of five groups. The control group were given distilled water, while the other groups were given equal amounts of reconstituted milk, milk kefir, soymilk, or soymilk kefir (10 per cent).
After three weeks of supplementation the researchers reported that blood levels of the IgE and IgG1, both associated with an allergic response, were decreased in the kefir supplemented groups, compared to control and normal (soy)milk groups.
Both milk kefir and soymilk kefir supplements were associated with about a 66 and 50 per cent reduction in IgE and IgG1 levels, respectively.
Populations of intestinal bacteria were also found to be affected by the kefir supplements, with populations of the so-called beneficial bacteria Bifidobacterium spp. and Lactobacillus spp. both significantly increased, while levels of the potentially harmful bacteria, Clostridium spp., decreased.
Many studies, both epidemiological and animal, have reported that disorder of the intestinal microflora is closely related to food allergy development, said the researchers, suggesting that probiotics in the kefir could offer an interesting avenue of future study.
"These results suggest that milk kefir and soymilk kefir may be considered among the more promising food components in terms of allergy prevention and enhancement of mucosal resistance to gastrointestinal infection," concluded the researchers.
Sharon Matthews, an allergy specialist from the Isle of Wight NHS Primary Care Trust told the Society of Chemical Industry's magazine Chemistry & Industry (16 October) that while the scientists have reported that the kefir is able to reduce the levels of IgE in mice, this is still some steps away from food allergy.
"Many children have specific IgE to a food but are not allergic to it," she said.
"We need much more supportive evidence before a human trial could be contemplated."