Are fermented foods the key to good gut health?

Key points

• Fermented foods have been around for 1,000s of years and are seeing an increase in attention thanks to the potential links with gut health.
• Possible benefits of fermented food include easier digestion, greater availability of certain nutrients and increased numbers of ‘good’ bacteria in your system.
• You don’t have to eat huge amounts of fermented food to see potential benefits. Small amounts may be a better way to introduce them to your system.

Fermented foods are nothing new. They can be traced back 1,000s of years, but initially, it was more about preserving food than improving gut health.

These days, fermented foods for gut health are growing in popularity. This has occurred as we begin to understand what it means to have a healthier gut and what you could possibly do to help to improve your gut health. 

But what actually is fermented food? Why is it (apparently) so good for you? Are all fermented foods the same? We’ve got your top questions answered.

What is fermented food?

“Fermenting is a form of food preservation,” explains Registered Nutritionist, Sarah Gray. “It works by adding in bacteria or yeasts, or through creating an environment that promotes bacteria to grow and ferment naturally on the food.”

It's these bacteria that live inside your intestines that help you digest food and absorb nutrients. An increased understanding of how they work is showing that they may also play a role in other areas of health, such as mental wellbeing and immune health. 

The process of fermenting increases the bacteria, also known as gut microbiomes, and changes the taste and texture of the food. Some people may say that certain foods taste better after being fermented.

Flavours will depend on the ingredients used to ferment, but it often comes down to personal taste. 

Popular fermented foods include:

• kimchi 
• sauerkraut
• miso
• certain yoghurts 

You can also read about some of our other suggestions for food to improve your gut health.

Benefits of fermented food

1. The fermentation process breaks down some of the sugar and starches which could make these kinds of food easier to digest when they get to your stomach and intestines.
2. The bacteria that’s produced may help to create certain vitamins and other nutrients that wouldn't normally be available with the raw version of the food during digestion.
3. The bacteria that’s made could help to populate your insides with the “good” bacteria (also known as gut microbiomes) that may help to keep your gut happier and healthier.
4. They may help repopulate your gut with the bacteria it needs after you've had a course of antibiotics. You could take probiotics in tablet form (best to speak to your pharmacist about that). But fermented foods are one way you could balance your gut microbiome with a more natural source of these probiotics.

This doesn't mean that you should be eating a whole jar of sauerkraut every day. Eating a load of fermented food in one go if you aren't used to eating fermented foods could be too much for your digestive system. If you think you’re having some gut problems, you may need to speak to a health professional. 

Adding in small bits each day is one way to start. You could try adding some sauerkraut to your sandwich, kimchi on the side of a stir fry or use miso paste as a base for a soup.

Not all fermented foods are created equal. 

Just because you’re eating a food that has been fermented, doesn't mean it's going to have all these additional benefits.

Sarah gives us an example. “Yoghurt is a fermented food that usually contains probiotics, whereas some cheeses, which are also considered a fermented food, don’t necessarily contain these probiotics.”

So, if you’re searching for live probiotics when considering purchasing fermented food, look for words like ‘live and active cultures’. But if you’re unsure, speak to a registered nutritionist or Accredited Practising Dietitian to confirm which products would be most suitable for your diet. 

While there are lots of recipes out there to make your own fermented foods, buying commercially approved alternatives is an ideal way of increasing your fermented food intake safely.

Is fermented food good for kids?

When it comes to our children’s diet, Sarah explains that the most important thing is that kids eat a balance of whole foods from the core food groups. 
“Eating a range of foods can help add variety to their diet as they explore new tastes and textures,” she says.

Adding in some fermented foods for their gut health may help to increase that variety. A dietitian or nutritionist could help you decide which foods may be most suitable for your child.

Fermented foods are just a part of something bigger

As the research into gut health increases our knowledge, ways to improve our gut health will increase too. 

Fermented foods may be good for your gut, but as Sarah notes, “There’s not one single food everyone needs to eat more of. It’s about having an overall balanced diet.”

Experiment with new foods and flavours and see which ones could be included in your weekly family meal plan. Your gut – and taste buds – may thank you for it.

Sarah Gray is both a Registered Pharmacist and Registered Nutritionist with a particular interest in health education and helping people to take small steps to big change in their health journey. Sarah is the Head of Health and Nutrition on the healthylife Advisory Board.

Reviewed by the healthylife Advisory Board September 2021.