Why fermented foods are good for better gut health

The power of probiotics are well known in the likes of yoghurt, kimchi and sauerkraut. So which ones should we add to our diets and why?

Fermented foods have been around for thousands of years, but more recently have become easier to find in supermarkets and health food stores.

From kimchi and kefir to tempeh and sauerkraut, these foods are being eaten more widely. Here’s why they’re a healthy addition to our diet.

Why fermented foods are so good for you

Fermented foods contain edible bacteria, yeasts or mould that help to break down other ingredients, such as sugars.

Lactobacillus and bifidobacterium – probiotics found in foods such as yogurt and kefir – are some of the most common friendly bacteria found in fermentation.

“Fermentation is the transformation of foods by the activities of beneficial microorganisms,” CSIRO principal research scientist Dr Netsanet Terefe says.

“They produce different compounds and enzymes that transform a food into something more palatable.

“Fermentation primarily improves the safety and stability of food but it also improves the digestibility and helps nutrients be more easily absorbed by our body.”

What the science says on fermented foods

A recent study from Stanford University found a diet containing fermented foods may be particularly beneficial for gut health.

During a 10-week trial, healthy adults ate a high-fibre diet or one rich in fermented foods including yoghurt, kefir, fermented cottage cheese, kimchi, kombucha tea and fermented vegetables.

The fermented food diet resulted in better gut health, less inflammation and lower levels of a protein linked to rheumatoid arthritis and type 2 diabetes.

Dietitian and Dietitians Australia spokeswoman Milly Smith says fermentation allows bacteria or yeasts, known as probiotics, to grow in food.

“When we eat fermented foods, we put these good probiotics into our gut, which can help keep our digestive system healthy and in turn can help our bowel function and our immune system,” Milly says.

“Studies are even looking at how gut health improves our mood.”

What fermented foods to eat

Milly says fermented foods should only be added slowly to a well-balanced diet.

“A couple of serves a week is enough,” she says.

“Too much too quickly may cause an upset stomach, and fermented foods can also be quite acidic so sip water after eating these foods to protect tooth enamel.”

Yogurt: Yogurt is produced from fermented milk, and some yogurts are rich in probiotics, calcium, potassium and phosphorus.

Look for yogurt that contains live and active cultures or lactobacillus acidophilus.

Kefir: Kefir is like a drinkable yogurt. “It has a tart, sour taste that forms when bacteria and yeast combine with milk,” Milly says.

Kefir has been associated with good gut health, and research is being conducted into whether it can help lower cholesterol.

Miso: A staple of Japanese cuisine, miso is made from fermented soybeans.

It has a high salt content so it should only be eaten in small amounts – no more than about 6g per day.

Kimchi: This is a basic of Korean cuisine and consists mostly of salted and fermented vegetables such as cabbage and radish.

It has a spicy flavour and can be added to soups, noodles and rice dishes.

Kimchi is also rich in vitamins A and B, calcium and iron.

Sauerkraut: “Sauerkraut contains good probiotics when it is freshly fermented but some products in the supermarket get heat-treated, which kills off those probiotics,” Milly says.

“Look for varieties that come from the fridge.”

Kombucha: This drink is made with green or black tea, sugar, bacteria and yeast but, as yet, there is limited evidence about its potential health benefits.

Tempeh: A combination of fermented soybeans and fungus culture, tempeh is a good source of plant-based protein. Originating in Indonesia, it has a nutty taste.

“Dice it up, pan fry it and add it to a stir fry instead of chicken or beef,” Milly says.

Written by Sarah Marinos.