- Fermented foods are rich in probiotics and can increase gut microbiome diversity.
- Mass-produced, processed, fermented foods may not be as beneficial.
- A gut-health dietitian recommends eating a variety of fermented food and buying locally-made items.
Studies have shown that fermented foods, like sauerkraut and kimchi, are good for gut health.
Made when live bacteria or yeast are added to ingredients like tea, milk, or vegetables, fermented foods contain probiotics, which are the "good" bacteria in our guts.
Fermented food can increase the diversity of the gut microbiome, the trillions of microbes that live in the colon lining. This can impact digestion, the immune system, and the brain. Experts believe that the more diverse the microbial community, the healthier it is.
But with Big Food cashing in on this discovery, it's easy to be sold products that doesn't deliver.
"Lots of things are being mass produced at the moment in the fermented food space, and they're not necessarily as good quality," Tanzil Miah, a gut-health specialist dietitian at The Gut Health Clinic in London, UK told Business Insider.
A new lawsuit, for example, has claimed that someone would need to drink more than four cans a day of the "gut-friendly" soda Poppi, which claims to aid gut health, to receive any potential health benefits.
Miah shared her three top tips for getting the most benefit out of fermented foods.
Eat multiple servings per day
Miah eats two servings of fermented foods a day. This could mean around two to three tablespoons of yogurt or kefir, or 30 grams of aged cheese, she said.
There's compelling evidence to suggest that eating multiple servings of fermented foods daily can be beneficial for gut health.
A 2021 study from Stanford University found that people who ate around six servings of fermented foods a day for 10 weeks had increased microbiome diversity compared to those who ate a high-fiber diet. They also had reduced inflammation biomarkers.
Eat a variety of fermented foods
It's also important to eat a variety of different fermented foods, Miah said, because the gut microbiome thrives on diversity.
"We still haven't discovered all the secrets of the microbiome yet. But one of the things we know for sure is our gut microbiome loves diversity," Miah said.
Eating plant-based foods, probiotic foods, and prebiotic foods, which are found in plants like fruits, vegetables, nuts, and seeds, leads to a more diverse microbiome with more types of beneficial bacteria, she said.
Buy locally and check labels
Due to the explosion of the gut-health trend, sauerkraut, kimchi, and kombucha are now available at most grocery stores. But oftentimes, they're mass-produced and contain far more ingredients than you might realize, Miah said.
"They lose some of that goodness in the processing and batch production," she added.
Some might even be considered ultra-processed foods (UPFs) because they contain five or more ingredients, including some you wouldn't find in a regular kitchen. UPFs are linked to many health problems and typically contain little fiber and few nutrients, meaning they're not particularly nourishing for the microbiome.
Miah recommended buying locally-made fermented foods when possible or checking the nutritional labels of products in the store before buying them.
"Go to a local market or a farmer's market or something like that," she said.