TITLE:
Improving Effect of Acetic Acid Bacteria (Gluconacetobacter hansenii GK-1) on sIgA and Physical Conditions in Healthy People: Double-Blinded Placebo-Controlled Study
AUTHORS:
Soyogu Yamashita, Mariko Oe, Mamoru Kimura, Yohei Okuyama, Satoshi Seino, Daichi Kajiyama, Ryosuke Matsuoka, Yasunobu Masuda, Keiichi Tsukinoki
KEYWORDS:
Acetic Acid Bacteria, Gram-Negative Bacteria, Gluconacetobacter hansenii GK-1 (GK-1), Functional Food, Immune
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.13 No.6,
June
29,
2022
ABSTRACT: It is known that the consumption of bacteria such as
lactobacilli and bifidobacteria has beneficial effects on human immune
function. Most of them are Gram-positive bacteria, and there are few reports on
Gram-negative bacteria. In this study, we evaluated the effects of intake of Gluconacetobacter
hansenii GK-1 (GK-1), Gram-negative acetic acid bacteria, for 12 weeks on
physical condition and immune indices. We conducted a randomized, double-blind,
placebo-controlled, parallel-group study in 100 healthy adults. The subjects were randomized into the GK-1 and the placebo
groups. The diary-administered physical condition survey was conducted
during the study period. The evaluation of salivary sIgA levels, NK-cell
activity, and serum IFN-γ levels and
quality of life survey was conducted before, in 6 weeks, and 12 weeks after the
start of ingestion. Based on the physical condition survey, the cumulative
onset-days of symptoms were significantly suppressed in the GK-1 group compared
to the placebo group regarding the evaluation of 13 symptoms related to
immunity, every 3 weeks. Additionally, salivary sIgA levels per hour were
significantly increased in the GK-1 group compared with the placebo group at 6
and 12 weeks. Despite no significant differences in the NK-cell activity, serum
IFN-γ levels or quality of life
survey between the groups. Serum IFN-γ levels in the GK-1 group were significantly elevated at 12 weeks after the
start of ingestion compared with those before ingestion. In conclusion, intake
of GK-1 was shown to increase salivary sIgA levels and improve physical
condition. This suggested that oral intake of GK-1 may help maintain the immune
system.