Probiotic drinks such as Yakult and Vivit can alleviate the symptoms of pollen allergies, says Wageningen PhD scholar Yvonne Vissers. They do this by diminishing the amounts of certain proteins that cause hay fever. The probiotic drinks also stimulate the manufacture of allergy-inhibiting substances. Particularly good results were obtained with Lactobacillus plantarum lactic acid bacteria. Vissers describes her findings in the thesis she is due to defend on Friday 10 June.
Allergies are an excessive reaction by the immune system to foreign substances in the body, such as pollen, flakes of skin or house mites. In cases of pollen allergy, the body makes an immune protein known as IgE, which attacks the intruding pollen. This causes histamine to be released, which is responsible for the classic allergy symptoms such as a runny nose, sneezing, and red and watery eyes.
In collaboration with NIZO and Friesland Campina, Vissers studied the effect of five lactic acid bacteria on the immune systems of 62 patients with a birch pollen allergy. Five groups, each consisting of about ten test subjects, were given a probiotic drink every day for four weeks, with a control group receiving a placebo version of the drink with no bacteria in it. The researchers took blood samples before and after the treatment, and measured immune parameters such as IgE and other immune proteins. By creating this immunological blood profile before and after the intake of the probiotics or placebo, they could establish the effect of the bacteria on the immune system.
After four weeks it was clear that all the bacteria strains used caused a significant reduction in birch pollen-specific IgE. One of the strains, L. plantarum CBS125632, also set off a reduction in interleukin 5 and 13, signal substances which stimulate an allergic reaction. What is more, there was an increase in signal substances which actually reduce an allergic reaction. 'These bacteria strains offer good prospects for reducing birch pollen allergies', says Vissers.