It’s sticky. It’s stinky. It’s good for you. Natto has been a Japanese staple for generations. But why has this fermented soybean dish dominated Japanese tables for so long? While the answer may vary depending on who you ask the question, researchers have discovered their own compelling reason: Natto may help fight certain bacterial infections, thus increasing the overall longevity of those who eat it.
A research group led by Professor Eriko Kage-Nakadai of Osaka City University fed the larva of Caenorhabditis elegans, a small worm, a diet that included the bacteria used to make natto — Bacillus subtilis var. natto. When the worms reached adulthood, they were infected with two types of Gram-positive bacteria, Staphylococcus aureus and Enterococcus faecalis, and in both cases, the worms fed with B. subtilis (natto) survived longer than the control group. Their results were published in the Journal of Applied Microbiology.
“The probiotic B. subtilis has been shown to successfully eradicate the pathogen S. aureus in humans,” says Rina Katayama, lead author of the study, “so we were curious whether the variation in B . subtilis found in natto also had a similar effect with S. aureus as well as other gram-positive bacteria. ” The team also tested the worms with other strains of B. subtilis and, “we found that while they also increased host survival, the natto variation conferred the longest survival time.” says Professor Nakadai.
While this is great news for those cultures who are used to consuming natto and for those who wish to participate, there are a few things to note. The team fed a batch of worms with the probiotic natto after reaching adulthood and found no effect in preventing or alleviating bacterial infections, suggesting that there are critical developmental milestones that are particularly beneficial for consuming B. subtilis (natto).
In addition, the team tested the probiotic against the gram-negative bacteria Salmonella enterica and found no positive effect on host survival, suggesting that B. subtilis (natto) is not a panacea for all. bacterial infections, but selects against specific ones.
“While there is still a lot to explore and understand regarding the effect of the bacteria on humans,” Katayama says, “to the best of our knowledge, this is the first study to show that B. subtilis ( natto) confers specific resistance against gram-positive bacteria. ”
Video: Natto, the stinky and gooey soy snack
R. Katayama et al., Bacillus subtilis var. natto increases the resistance of Caenorhabditis elegans to Gram-positive bacteria, Journal of Applied Microbiology (2021). DOI: 10.1111 / jam.15156
Provided by Osaka City University
Quote: Natto: An All-Natural Bacteria-Fighting Probiotic (2021, June 24) retrieved September 27, 2021 from https://phys.org/news/2021-06-natto-bacteria-fighting-all-natural-probiotic.html
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