Sauerkraut and Gut Health: Benefits, Fermentation and Precautions

Sauerkraut is a fermented food that may contain live microorganisms when it has not subsequently been pasteurised or heated. Scientific research has investigated the possible relationship between fermented foods, the gut microbiota and certain health indicators, but the effects are not universal and are still not fully established.

In summary: sauerkraut is cabbage fermented with salt and may contain bacteria resulting from fermentation. It can contribute to a varied diet and research is being conducted into its relationship with the gut microbiota, but it should not simply be presented as a “probiotic” food or as a guaranteed way of improving gut health.

What is sauerkraut?

Sauerkraut is essentially cabbage that has undergone a fermentation process, traditionally using salt.

During fermentation, a community of microorganisms develops, including lactic acid-producing bacteria. These microorganisms transform components of the food and contribute to the characteristic flavour, aroma, texture and preservation of sauerkraut.

Fermentation is an ancient food process used in different cultures. In fermented vegetables, the composition of microorganisms can vary according to the raw material, amount of salt, temperature, fermentation time and other processing conditions.

A little history

The history of sauerkraut is associated with ancient techniques for preserving vegetables through fermentation. A possible origin involving fermented cabbage preparations in China and their subsequent spread to other regions of Asia and Europe is often mentioned.

However, the exact history of the origin of sauerkraut has not been completely established. It is therefore more accurate to speak of a long tradition of vegetable fermentation than to attribute its origin to a single people or historical event.

Sauerkraut became particularly important in several regions of Central and Eastern Europe, where fermenting cabbage made it possible to preserve this food for longer periods.

There are also historical records of sauerkraut being used during sea voyages. Captain James Cook is often associated with the use of sauerkraut during his voyages as part of the dietary strategies used to reduce the risk of scurvy. Scurvy is associated with prolonged vitamin C deficiency, and the diet of sailors was an important consideration during long sea voyages.

How does sauerkraut fermentation work?

During sauerkraut fermentation, microorganisms naturally present on the cabbage participate in the transformation of available sugars into different compounds, including lactic acid.

This process progressively changes the environment of the food, contributing to its characteristic acidic flavour and preservation.

The amount of salt, temperature, fermentation time, availability of oxygen and other conditions influence the final result. Therefore, not all homemade or commercially produced sauerkraut will have exactly the same microbial composition.

Sauerkraut and the gut microbiota

One of the reasons why sauerkraut has attracted scientific interest is the possibility that fermented foods may influence the gut microbiota.

However, it is important to distinguish between a biological possibility and a demonstrated clinical effect.

Does sauerkraut contain live bacteria?

Unpasteurised or unheated sauerkraut may contain live microorganisms resulting from fermentation. Products that have been pasteurised or subjected to heating may contain much lower numbers of live microorganisms or none at all.

This does not, however, mean that a pasteurised product ceases to be a fermented food or automatically loses all of its nutritional characteristics.

Is sauerkraut a probiotic food?

Not all fermented foods are probiotics.

The term probiotic is used more specifically for live microorganisms that, when administered in an adequate amount, have been demonstrated to provide a health benefit.

Therefore, it is not scientifically correct to simply state that all sauerkraut is “a probiotic”. The composition of microorganisms present in sauerkraut can vary and, in most traditional products, there is not enough characterisation of specific strains to support a probiotic claim.

What do human studies say?

Human research is still relatively limited, but there are some interesting studies.

In an intervention trial published in 2025, 87 healthy adults consumed fresh or pasteurised sauerkraut daily for four weeks. Changes were observed in some bacterial species in the gut microbiota, which were more pronounced in the group consuming pasteurised sauerkraut. However, the authors concluded that the gut microbiota of healthy individuals showed considerable resilience to this short-term intervention.

Another clinical trial published in 2026 also evaluated 87 healthy adults who consumed 100 g per day of fresh and pasteurised sauerkraut for four weeks. A small reduction in systolic blood pressure and modest changes in certain markers were observed, but there were no changes in gut barrier integrity and no appreciable systemic health benefit after four weeks.

These findings are interesting, but they do not allow us to conclude that consuming sauerkraut produces general gut-health benefits in everyone.

What are the potential benefits of sauerkraut?

Gut health and the microbiota

The consumption of fermented foods, including sauerkraut, is an active area of research. Fermentation can alter the nutritional composition of foods and produce different biologically active compounds.

Sauerkraut should not, however, be presented as a guaranteed way of “replenishing” or “rebuilding” the gut flora. The human microbiota is complex and is influenced by many factors, including overall diet, medication, age, physical activity, health status and environment.

Digestion

Fermentation transforms some components of the food and may modify its digestibility and nutritional characteristics.

There is also research into sauerkraut consumption among people with gastrointestinal symptoms. A small pilot study involving 34 people with irritable bowel syndrome found an improvement in symptoms after six weeks of consuming fermented sauerkraut, both fresh and pasteurised.

Although interesting, this was a small study and its results are not sufficient to conclude that sauerkraut improves digestion or intestinal symptoms in general.

Nutrients and compounds resulting from fermentation

Fermentation can modify some components of foods and contribute to the formation of different compounds. The nutritional value of sauerkraut also depends on the cabbage itself, the amount of salt used and the production process.

For this reason, sauerkraut can be included in a varied diet, but it should not be treated as a “superfood” capable of replacing a balanced diet.

What science does not yet allow us to claim

It is important to distinguish potential benefits being studied from claims that do not yet have sufficient scientific support.

At present, we cannot claim that sauerkraut:

• “repopulates” the gut with beneficial bacteria;
• necessarily improves the gut flora;
• directly strengthens the immune system;
• improves digestion in everyone;
• prevents disease simply because it is fermented;
• produces the same effects in everyone;
• needs to be consumed in a specific amount to produce health benefits.

Research into fermented foods continues to evolve, and results depend on the type of food, fermentation process, microbial composition and population studied.

Fresh, pasteurised or cooked sauerkraut?

If the aim is also to consume the live microorganisms present in unpasteurised sauerkraut, heating can alter this component.

However, this does not mean that cooking or heating sauerkraut “destroys all its properties”. The food continues to provide the nutrients and components of the cabbage itself, as well as compounds resulting from fermentation.

There are also commercially pasteurised sauerkrauts that remain foods produced through fermentation, even though they may no longer contain live microorganisms.

Therefore, the choice between fresh and pasteurised sauerkraut depends on the product and the intended dietary purpose. It is not correct to state that one is universally better for everyone.

How much sauerkraut should you eat?

There is no universal amount of sauerkraut that can be considered necessary to obtain gut-health benefits.

A sensible approach is to use it as an accompaniment to a varied diet, starting with small amounts if you are not accustomed to fermented foods.

As with other foods, individual tolerance should be considered. Some people may experience gas, abdominal bloating or discomfort when they rapidly increase their intake of fermented foods.

Sauerkraut and salt

Salt is not used only for flavour. In traditional sauerkraut fermentation, the amount of salt plays an important role in the texture and development of the fermentation process.

For this reason, it is not advisable to arbitrarily reduce the amount of salt in a fermentation recipe. The National Center for Home Food Preservation, based on USDA recommendations, emphasises that salt is important for the safety and texture of fermented sauerkraut and recommends not altering the proportions of tested recipes.

At the same time, sauerkraut can contribute significantly to daily sodium intake. People who need to limit sodium in their diet should take this into consideration and consult a healthcare professional when necessary.

Who should take particular care?

Sauerkraut can form part of the diet of many people, but it should not be considered suitable in any quantity or in every situation.

Particular attention should be paid to its salt content when there is a need to control sodium intake.

If you have a diagnosed gastrointestinal condition, persistent symptoms or a medical condition requiring specific dietary restrictions, regularly introducing large amounts of fermented foods should be discussed with a healthcare professional.

How to choose sauerkraut

When buying sauerkraut, check the ingredients list and the storage method.

If you are looking for a product that may contain live microorganisms, check whether it is unpasteurised and whether it is stored according to the manufacturer’s instructions.

It is also important to distinguish traditional sauerkraut from cabbage products preserved solely with vinegar or through other acidification methods. Not every acidic cabbage product has necessarily been fermented.

How to make sauerkraut at home

Sauerkraut can be prepared at home by fermenting cabbage with salt. However, home fermentation requires attention to ingredient proportions, hygiene, the container, temperature and fermentation conditions.

The original recipe in this article specified only an approximate amount of salt and a fermentation period of 8–10 days. These parameters should not be treated as a universal guarantee of safety because fermentation depends on the specific conditions of the process.

For home preparation, it is preferable to follow a tested food-preservation recipe. The National Center for Home Food Preservation, based on USDA recommendations, provides a sauerkraut recipe using specific proportions of cabbage and salt, keeping the cabbage submerged in brine and allowing fermentation to take several weeks, depending on temperature.

Important principles for home fermentation

• Use fresh cabbage in good condition.
• Use a container suitable for contact with food.
• Follow exactly the salt proportions specified by the tested recipe you are using.
• Keep the cabbage submerged in the brine during fermentation.
• Avoid changing the recipe proportions without an appropriate technical basis.
• Control the fermentation conditions according to the chosen recipe.
• Once fermentation is complete, store the sauerkraut according to the recipe’s recommendations.

A home-preservation reference from the National Center for Home Food Preservation indicates, for its sauerkraut recipe, approximately 3 to 4 weeks of fermentation at 21–24 °C, with the process potentially taking longer at lower temperatures. The same source recommends keeping the cabbage covered by the brine during fermentation.

Important: a fermentation recipe should not be adapted simply by reducing the amount of salt or shortening the fermentation time. For home preparations, always use a tested recipe and follow its proportions and instructions.

How to eat sauerkraut

Sauerkraut can be used as an accompaniment to meals, in salads or as a complement to other foods.

It can be interesting to include it in a varied diet together with vegetables, fruit, pulses, whole grains, nuts, seeds and other sources of fibre.

If the aim is to preserve the live microorganisms present in an unpasteurised product, avoid heating it intensely. However, there is no need to consider raw sauerkraut the only nutritionally valid way of consuming it.

Conclusion

Sauerkraut is a traditional food obtained by fermenting cabbage with salt and can be an interesting way of diversifying the diet.

Current scientific research suggests that fermented foods may interact with the gut microbiota and other aspects of human physiology, but the specific health benefits of sauerkraut are still being investigated.

Therefore, rather than looking to sauerkraut as a solution for “replenishing the gut flora”, it is worth considering it for what it actually is: a fermented food with a long tradition, its own nutritional characteristics and potential health interest that continues to be investigated.

Frequently asked questions about sauerkraut

Scientific references and sources

• Marco ML, Sanders ME, Gänzle M, et al. The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on fermented foods. Nature Reviews Gastroenterology & Hepatology. 2021.
• The impact of regular sauerkraut consumption on the human gut microbiota: a crossover intervention trial. 2025.
• Fermented foods and inflammation: a crossover intervention trial with fresh and pasteurized sauerkraut. European Journal of Clinical Nutrition. 2026.
• Lacto-fermented sauerkraut improves symptoms in IBS patients independent of product pasteurisation: a pilot study. Food & Function. 2018.
• National Center for Home Food Preservation / USDA. Sauerkraut.

Scientific knowledge about fermented foods continues to evolve. Available results should be interpreted according to the type of food, fermentation process, population studied and duration of the interventions.

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