REACHING OUT for homemade yoghurt or kimchi to reset your gut bacteria after about of illness?
Wait a minute, according to researchers Hua Wang and colleagues at The Ohio State University in Columbus, USA – these artisanal (traditionally processed) fermented foods have high levels of antibiotic-resistant bacteria (superbugs) in them that could do more harm than good.
Examining ten types of kimchi and four types of artisanal cheeses purchased from local Korean and Japanese restaurants, and large and independent supermarkets in Ohio, Wang and colleagues discovered that nine of the kimchi products and all the cheeses contained antibiotic-resistant bacteria. Some of these bacteria include Klebsiella pneumoniae and Enterococcus, which are the main culprits of many difficult-to-treat hospital infections.
The Latilactobacillus bacteria responsible for driving kimchi fermentation, and thought to be good for our gut health, were also resistant to various commonly dispensed antibiotics. Stool samples from healthy human volunteers who consumed these products for ten weeks showed more antibiotic resistance genes than those who ate a diet rich in plant fibres. These findings suggest that antibiotic-resistant microbes in fermented foods like kimchi can increase the collection of antibiotic resistance genes in our gut.
When bacteria from the artisanal cheeses were grown on agar plates with and without antibiotics, they found that the dominant bacteria on both plates were different.
Plates without antibiotics had more opportunistic bacteria – germs that become harmful only when our body is weak, ill, or exposed to medication – while plates with antibiotics had more pathogenic bacteria – germs that make us ill. Further, Lactococcus bacteria in the cheese starter culture that are beneficial for our gut were absent from the plates with antibiotics.
What this means is that besides increasing the antibiotic resistance gene pool in our gut, antibiotic-resistant bacteria from artisanal fermented foods could also disturb the population of beneficial gut bacteria when we take antibiotics.
Understanding Fermentation: Natural Process vs Risks
Using microorganisms like bacteria and yeast to convert carbohydrates such as starch or sugar into alcohol or acid without oxygen is called fermentation.
Fermentation is one of the most ancient and natural ways of preserving foods. The alcohol or acids produced during fermentation give foods their distinctive colour, texture, aroma, and flavour. Beer, wine, kombucha, cheese, yoghurt, and certain sour foods like kimchi and kasam, consumed by Sarawak’s Dayak community, are all made through fermentation.
Even the lactic acid formed in your muscles after intense exercise is a result of fermentation. Without fermentation, cows couldn’t digest the grass fibres they eat to obtain energy.
To kickstart and control the fermentation process in foods, starter cultures containing one or more lactic acid bacteria are used.
While mainstream dairy fermentation uses pasteurised milk and carefully selected starter cultures, traditionally fermented products like kimchi still rely on lactic acid bacteria naturally found on the cabbage itself to drive the fermentation process.
What Should You Do?
While fermented foods offer many potential benefits, it’s important to consider where they’re sourced and how they’re prepared. Opting for well-screened, professionally produced products or consulting with a healthcare provider may help reduce the risks associated with antibiotic-resistant bacteria. Understanding the balance between the benefits and risks of fermented foods will help you make informed choices about what’s best for your gut health.
