Allergic diseases are immunoglobulin E (IgE)-mediated type I inflammatory disorders which are increasing in prevalence.
Lactic acid bacteria (LAB) is a generic name given to Gram-positive bacteria that produce a large amount of lactic acid. LABs are generally non-pathogenic and many strains produce functional substances that have health benefits for humans, with some strains regarded as probiotics.
The authors of the current study, from Hiroshima University, in Japan, have isolated many LABs from natural sources, especially from raw plants, including fruits and medicinal herbs, creating a plant-derived LAB library of more than 1000 strains.
Exopolysaccharides (EPS) are extracellular macromolecules which play a role against desiccation, phagocytosis, cell recognition, phage attack, antibiotics or toxic compounds and osmotic stress.
The team have found, in animal studies, the EPSs produced by the strain Lactobacillus (Lb.) paracasei IJH-SONE68 (isolated from a fig leaf) can prevent eczema (specifically picryl chloride-induced contact dermatitis) and IBD (specifically dextran sulfate sodium (DSS)-induced ulcerative colitis), by repressing the accelerated expression of interleukin (IL)-4 and the serum IgE level and by reducing the MIP-2 expression.
As the next step, in the present study, the team aimed to show that IJH-SONE68-derived EPSs improve allergic conditions in humans with perennial allergy symptoms.
This double-blind, randomised, placebo-controlled parallel-group study was conducted at Hiroshima University from May 2019 to July 2021.
A sample of 57 subjects (aged 21–70) were randomly divided into the IJH-SONE68-intake group or the placebo group.
The subjects were instructed to take four capsules of either the IJH-SONE68 (1040 mg) or the placebo daily for 12 weeks. They were also directed to keep their ordinary dietary habitats.
The primary outcomes of the study were changes in the self-assessment questionnaire and VAS value, and the secondary outcomes were changes in the serum total IgE and specific IgE (for 2 types of house dust, Gramineae pollen, weed pollen, animal dander, and fungi) levels.
The subjects visited Hiroshima University for physical examinations every 4 weeks for serum total IgE measurements, self-assessment questionnaire and visual analogue scale (VAS, indicating difficulty in daily life activities), and serum specific IgE and biochemical measurements and urinalysis (at 12 weeks). Blood samples were obtained, body fat percentage was measured and blood pressure was measured.
According to the self-assessment questionnaire scores, the average scores for each of the six items (frequency of sneezing, frequency of blowing nose, nasal congestion, itchy eyes, watery eyes, head dullness) decreased in both groups. The scores for four of the items decreased more in the IJH-SONE68 group than in the placebo group.
The average parameters for serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and cholinesterase (ChE), biomarkers of cell injury, were decreased from the baseline in the IJH-SONE68 group, and the changes in those parameters were significant when compared with the placebo group.
The report concludes: "The oral administration of the spray-dried powder derived from the culture broth of Lb. paracasei IJH-SONE68, has been shown to significantly improve the scores based on subjects’ self-assessment of allergic status in the present clinical study. The present outcome demonstrates that the IJH-SONE68 strain can be expected to help persons with perennial allergies and decrease inconvenience."
Noda, M.; Kanno, K.; Danshiitsoodol, N.; Higashikawa, F.; Sugiyama, M.
"Plant-Derived Lactobacillus paracasei IJH-SONE68 Improves Chronic Allergy Status: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial"