The last two decades have seen a sharp increase in seasonal allergic reactions caused by pollen of the Japanese cedar. This so called ‘national affliction’ with seasonal allergic rhinitis (SAR) caused by the cedar pollen is now the most common disease in Japan, and affects more than one third of the population, according to a 2013 study.
Now, researchers writing in the European Journal of Nutrition, have suggested that consumption of probiotics could be a potential method of protection against this disorder.
Led by Gaku Harata from Takanashi Milk Products and the Functional Foods Forum at the University of Turku, the team noted that while an altered gut microbiota has been associated with several disease states – including allergic diseases – very few studies have investigated the underlying mechanisms of Japanese cedar pollinosis (JCP), while “probiotic effects remain unclear.”
“In addition, this study is the first observation of the correlation between the gut microbiota and blood lipid in JCP,” wrote the team behind the study.
Given the widespread nature and rapidly growing incidence of the condition, researchers have noted the pressing need for new preventative and therapeutic measures.
Currently, to minimize symptoms, many Japanese people wear facemasks and eyeglasses at all times between February and April, in a bid to prevent exposure to Japanese cedar pollen. Furthermore, forecasts for JCP levels typically follow weather forecasts and real-time JCP data is readily available online.
Prophylactic treatment with antihistamines and antileukotrienes before the start of the Japanese cedar pollen dispersion season is currently widely recommended, however a 2013 study by Takechiyo Yamada suggested that many people with JCP do not find satisfactory relief with such therapies and that work is needed to identify new therapeutic pathways.
Microbiota and JCP
Harata and colleagues performed a 10 week trail in which participants suffering with JCP consumed either a fermented milk containing the probiotic strain LGG–TMC0356 or a control containing no probiotic strain.
The team took feacal samples from the 25 participants both before and after the 10-week trial. Samples were used to characterize gut microbiota composition used DNA sequencing of 16S rRNA genes.
“16S rRNA-based operational taxonomic unit clustering of the microbiota revealed that LGG–TMC0356-fermented milk significantly altered gut microbiota after 10 weeks of milk consumption, and eight dominant genera of microbes were detected,” wrote the Japanese team.
“During the JCP season, the Bacteroidetes/Firmicutes ratio, when compared to baseline, was significantly decreased in subjects at end of the study,” they added – noting that Bacteroidetes showed positive correlation with LDL- and HDL-cholesterol levels, whereas Firmicutes showed negative correlation with total cholesterol, LDL- and HDL- cholesterol.
They added that the altered gut microbiota witnessed via supplementation with fermented milk containing a probiotic “may be a prospective target for protection against JCP, with beneficial effects on blood lipid levels.”
Source: European Journal of Nutrition
Pages 1–9, doi: 10.1007/s00394-016-1264-3
“Probiotics modulate gut microbiota and health status in Japanese cedar pollinosis patients during the pollen season”
Authors: Gaku Harata, et al