• "...fermented foods like sauerkraut, yoghurt and kimchi are worth tasting and making if you love being connected to food." (iStockphoto/Getty Images)Source: iStockphoto/Getty Images
There's a lot of hype about the gut-friendly health benefits of traditional fermented foods, but not all fermented foods are made the same way. So, which ones are good for your gut and why?
Yasmin Noone

20 Oct 2021 - 12:12 PM  UPDATED 11 Nov 2021 - 10:30 AM

Some adults reflect on food memories sprinkled with fairy floss or ice cream. For ‘The Fermentier’, Tania Wiesmayr-Freeman, reminiscing about close encounters with sauerkraut eaten at German feasts in her youth sparks a feeling of cultural joy.

As the fermented food specialist tells SBS, her childlike self didn’t really grasp the true health or flavour glory of sauerkraut at the time. These days, however, it’s quite the opposite.

The Accredited Practicing Dietitian relishes her Austrian connection to the lacto-fermented vegetable dish and now makes raw sauerkraut and fermented non-alcoholic beverages for sale.

“I just love the kinaesthetic aspect of making sauerkraut, especially when I squish salted cabbage to make the brine come out,” Wiesmayr-Freeman says. “I love transforming basic foods into something special through the process of fermentation.”

“I just love the kinaesthetic aspect of making sauerkraut, especially when I squish salted cabbage to make the brine come out."

Wiesmayr-Freeman is also a fan of the gut-friendly benefits people can receive by eating fermented goods. However, as a nutrition scientist, she has to declare that the health benefits of fermented foods are “often exaggerated in the public domain. Companies say all kinds of things on fermented food labels that actually are not [scientifically] substantiated”.

The fermentation expert explains there is not a vast array of studies proving all the advantages of fermented products but there is ‘emerging evidence’ that suggest fermented foods do have some health benefits. “What the experts have seen in animal and test-tube studies, and small human trials is that fermented foods should be consumed regularly as part of a healthy diet.”

Knackwurst with sauerkraut

German knackwurst sausages are made from pork and are already cooked when you purchase them, which is why it takes only a few minutes to heat them through before serving.

So how do fermented foods work in our bodies?

Some fermented foods are good for us because they contain live microbes. When we consume these active bacteria, we increase the diversity of our gut bacteria.

“We always need good and bad bacteria in our guts to maintain a positive balance. When we eat fermented products, the beneficial bacteria from the fermented foods pass through the gut and outnumber the bad bacteria out.

"In doing this, they help the good bacteria to compete with the bad bacteria, and improve our gut health and immune system. They may also assist us in managing anxiety and depression, and potentially Alzheimer's and Parkinson's disease.”


However, Wiesmayr-Freeman says, there is one health caveat. Not all fermented goods, from sourdough to tamari sauce to beer, will confer the above benefit: only those that contain live active bacteria.

“Fermentation is when you’ve got a beneficial microbial growth that transforms one food into another new food,” says Wiesmayr-Freeman, who is also a lecturer in nutrition and dietetics at the University of the Sunshine Coast.

“But, if you cook a food [that’s been fermented] above 40 degrees Celsius, you start to sterilise or pasteurise it. So the sauerkraut you buy in a jar that sits in the shelf will have been pasteurised. If you bought sauerkraut containing live active bacteria in it, it would be in the fridge section.”

Live bacteria hibernate in cold temperatures, so when a fermented product is placed in the fridge, bacteria remain “suspended in space until you wake them up or take them out of the fridge to eat”.

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Fermented products that retain live fermentation microbes include sauerkraut, yoghurt, kimchi, most kombuchas, tempeh, miso and kefir water. Fermented products that no longer contain fermentation microbes after being baked or heat-treated are bread, shelf-stable pickles, vinegar and soy sauce. 

Cheese, however, is a tricky one. In fact, it's the perfect example of fermented food that may or may not contain live bacteria.

“All cheese is fermented,” says CEO and head cheese-maker of Woodside Cheese Wrights, Kris Lloyd. “But not all cheese contains live active microbes.”

Lloyd, who is also the festival director of Adelaide’s CheeseFest, explains that curds are usually heated at a higher temperature to make harder cheeses like cheddar and Parmesan. That means that cheddar and Parmesan are unlikely to convey the same gut-friendly benefits as other softer cheeses.

“Once you heat the curds at a high temperature, you may destroy the live microbes and enzymes,” Lloyd tells SBS. “So the softer, fresher and more moist cheeses are the ones that would be better for your gut.”

Lloyd’s pick of the most gut-friendly cheeses includes, “blue cheese, Persian feta and goat’s curd”.

If in doubt, "source your cheese from a farmer’s market and speak with the producer to find out how they made the cheese if it is treated at a high heat and where the milk comes from”.

“All cheese is fermented. But not all cheese contains live active microbes.”

Cautious fermentation

The gut-balancing benefits reaped from the consumption of a fermented product also depends on the person eating it, their gut and their state of health.

“If you have a very sensitive gut or are on a FODMAP diet, you may need to be careful and introduce fermented foods into your diet very slowly so you know you will be okay with it,” Wiesmayr-Freeman says. 

Individuals who are on cancer therapy or have a reduced immune system should check with their doctors whether they are okay to eat fermented foods as it may disturb the balance of their gut bacteria.

“My recommendation to everyone else is that fermented foods like sauerkraut, yoghurt and kimchi are worth tasting and making if you love being connected to food.

“But they should always be eaten as part of a healthy, balanced diet. We should all eat raw fermented vegetables, just as we should all eat grains and vegetables. Basically, we should just enjoy the abundance of the many different but fabulous foods we’ve got around us.”


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