The 5 best probiotic foods for a healthy gut

What are probiotic foods?

In recent years, the word 'probiotic' has been plastered on yoghurt pots, cereal bars, and fermented drink labels in the supermarket. These products claim to boost the number of probiotics in your gut, which in turn is thought to keep it healthy.

We all naturally have probiotics, regardless of whether we add them in our diet consciously through probiotic foods or supplements. These probiotics are tiny creatures that live in the digestive system. They go by several different names - to scientists they are known as microbes; to the public they are often called 'beneficial' or 'good' bacteria.

What foods contain probiotics?

Fermented foods are naturally high in probiotics. This is because fermentation involves growing live and active cultures, called live bacteria. These natural probiotic foods are healthy and safe to eat, whether you are concerned about your gut health or not.

If you do have a digestive problem - such as regular diarrhoea, bloating, or IBS - you can consume them regularly as a form of complementary treatment, alongside any medication.

What are the best probiotic foods?

The following probiotic foods have shown promising health benefits in some people.

Plain yoghurt

Plain yoghurt which hasn't been sweetened is rich in probiotics. It is also one of the most easy to find fermented probiotic foods, as natural yoghurt generally isn't limited to large supermarkets or speciality stores.

Yoghurt is made through fermenting milk. The probiotics in this milk consume the naturally occurring milk sugars, turning it into lactic acid. This process may sound peculiar, but this is what gives plain yoghurt the creaminess and slightly sour taste that many of us enjoy.

Probiotic foods need to be consumed on a regular basis, and to contain enough probiotics, for us to see noticeable health benefits. Because of this, some yoghurts also have added probiotics for gut health and overall health. Experts suggest consuming around 10 billion CFU (colony forming units) per day¹⁰. This is the measure of good bacteria in probiotic foods and probiotic supplement products. However, it's important to note that not everyone will feel the benefits of probiotics, regardless of how much they consume.

Kefir

In recent years, you may have noticed kefir products appearing in the dairy section of your local supermarket. This is a drink made from fermented milk, kefir grains, yeast, and friendly bacteria.

Kefir is one of the most widely researched fermented probiotic foods. There has been at least one high-quality randomised controlled trial demonstrating that kefir destroys harmful gut bacteria and helps symptoms of lactose intolerance¹¹.

Some experts believe that probiotic foods such as kefir may also be useful in cancer prevention and treatment. Studies indicate that kefir can block some cancer cells, including breast cancer, lung cancer, and colorectal cancer¹². Research into this area is ongoing.

Sauerkraut

Sauerkraut is cabbage that has been fermented by lactic acid bacteria, giving it a distinct sour taste. Originating in Germany, it is often used as a side dish, and has a long shelf-life. The fermentation of this probiotic food has been studied for many years.

As well as helping to resolve problems of the gut, such as constipation, it is also thought that the good bacteria in sauerkraut may be useful in the protection against cancer, obesity, and high cholesterol, amongst other health issues¹³.

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Kimchi

Another popular probiotic food made from fermented cabbage is kimchi, this time originating from Korea. Compared to sauerkraut, kimchi is fermented with many more ingredients - including other vegetables and seasonings - which gives it an even more complex micro-ecosystem of live bacteria strains.

As Kimchi is also a good source of probiotic lactic acid bacteria, this probiotic food has the same potential health benefits as sauerkraut.

Kombucha

Kombucha is a fermented tea drink that's available in many UK stores and supermarkets. Fermentation begins when sugar and several probiotic bacteria strains are added to green or black tea and then left for a week or longer. Kombucha contains a diverse range of good bacteria, including lactic acid, acetic acid, fungi, and yeasts.

Yet, while these probiotic properties are promising, there's little direct evidence of kombucha's benefits for human health¹⁴. Most experts agree that more robust research is needed.

Do probiotics work?

Fermented foods provide a range of health benefits. As most also contain antioxidants, anti-inflammatory, and immune-supporting properties, these benefits extend beyond probiotics and gut health.

However, experts generally agree that more research is needed in the form of high-quality clinical human trials.

Are probiotics safe?

The choice to try food sources rich in probiotics is entirely yours. These foods are generally considered safe to consume on a regular basis and few reports of negative outcomes can be found.

Are all pickled food types probiotics?

It's easy to mistake pickled foods for fermented foods, but there is a key difference when it comes to what's good for your gut. In fact, most pickled foods don't contain beneficial probiotics for gut health.

What about unfermented foods?

These days, there are many unfermented food products on the market that have had probiotics added to them. According to the National Institutes of Health (NIH), whether these manufactured probiotic foods can truly count as probiotics comes down to three factors:

• How many micro-organisms they contain.

• If they survive digestion.

• If the bacteria strain they contain has health benefits.

Common manufactured probiotic foods include some:

• Milk drinks.

• Cereals.

• Cereal bars.

• Teas.

• Juices.

Further reading

1. Judkins et al: Probiotics, nutrition, and the small intestine.

2. Hungin et al: Systematic review: probiotics in the management of lower gastrointestinal symptoms.

3. Ibrahim et al: Fermented foods and probiotics: an approach to lactose intolerance.

4. Ghouri et al: Systematic review of randomized controlled trials of probiotics, prebiotics, and synbiotics in inflammatory bowel disease.

5. Camilleri: Human intestinal barrier: effects of stressors, diet, prebiotics, and probiotics.

6. Fata et al: Probiotics and the gut immune system: indirect regulation.

7. Huang and Jiang: Effect of probiotic supplementation in pregnant women.

8. Akgul and Karakan: The role of probiotics in women with recurrent urinary tract infections.

9. Rittiphairoj et al: Probiotics contribute to glycemic control in patients with type 2 diabetes mellitus.

10. National Institutes of Health: Probiotics.

11. Dimidi et al: Fermented foods: definitions and characteristics, impact on the gut microbiota and effects on gastrointestinal health and disease.

12. Sharifi et al: Kefir: a powerful probiotics with anticancer properties.

13. Kumar Das et al: Lactic acid bacteria in food biotechnology: chapter 3.

14. Kapp and Sumner: Kombucha: a systematic review of the empirical evidence of human health benefit.

Judkins et al: Probiotics, nutrition, and the small intestine.

Hungin et al: Systematic review: probiotics in the management of lower gastrointestinal symptoms.

Ibrahim et al: Fermented foods and probiotics: an approach to lactose intolerance.

Ghouri et al: Systematic review of randomized controlled trials of probiotics, prebiotics, and synbiotics in inflammatory bowel disease.

Camilleri: Human intestinal barrier: effects of stressors, diet, prebiotics, and probiotics.

Fata et al: Probiotics and the gut immune system: indirect regulation.

Huang and Jiang: Effect of probiotic supplementation in pregnant women.

Akgul and Karakan: The role of probiotics in women with recurrent urinary tract infections.

Rittiphairoj et al: Probiotics contribute to glycemic control in patients with type 2 diabetes mellitus.

National Institutes of Health: Probiotics.

Dimidi et al: Fermented foods: definitions and characteristics, impact on the gut microbiota and effects on gastrointestinal health and disease.

Sharifi et al: Kefir: a powerful probiotics with anticancer properties. https://pubmed.ncbi.nlm.nih.gov/28956261/

Kumar Das et al: Lactic acid bacteria in food biotechnology: chapter 3. https://www.sciencedirect.com/science/article/abs/pii/B9780323898751000134

Kapp and Sumner: Kombucha: a systematic review of the empirical evidence of human health benefit.https://www.sciencedirect.com/science/article/pii/S1047279718307385