Thursday October 29, 2026 (foodconsumer.org) – Sauerkraut has a reputation as a gut-friendly food that fights inflammation. A new trial from Germany put that reputation to the test, and the result is mixed. Eating a side of sauerkraut every day lowered blood pressure a little. It did not measurably reduce inflammation.

The study, published in June in the European Journal of Clinical Nutrition, also turned up a surprise. Pasteurized sauerkraut, the shelf-stable kind with no live bacteria left in it, lowered blood pressure just as much as fresh sauerkraut did. "Live bacteria are not essential for the hypotensive potential of sauerkraut," the researchers wrote.

How the sauerkraut study worked

A team at the University of Freiburg led by epidemiologist Karin Michels recruited healthy adults through newspaper ads, flyers and social media. Eighty-seven people between the ages of 21 and 69 made it into the final analysis. Smokers, people with diabetes or diagnosed high blood pressure, and anyone who had recently taken antibiotics were left out.

Each volunteer ate 100 grams of sauerkraut a day, about half a cup, for four weeks. Then they switched to the other version for another four. Half the group started with fresh sauerkraut and half with pasteurized. Before each round came a four-week break with no fermented foods at all, so one round wouldn't spill into the next.

The fresh sauerkraut, from a local organic producer, contained live lactic acid bacteria, mostly Lacticaseibacillus paracasei, though not in especially large numbers. The pasteurized version had been heated to 75 °C (167 °F) for five minutes, and lab tests found no live bacteria in it.

At the end of each phase, participants gave a fasting blood sample and had their blood pressure checked. The lab measured markers of inflammation and blood sugar control. It also measured signs of gut-barrier health, the lining that is supposed to keep bacterial toxins out of the bloodstream and that is often discussed under the label "leaky gut."

Does sauerkraut lower inflammation or blood pressure? The results

The blood pressure drop was real but small. Systolic pressure, the top number, fell by roughly 1.5 to 2.5 mmHg after either kind of sauerkraut. The authors point out that a 5 mmHg drop has been linked to about a 10% lower risk of heart attack and stroke, so this effect is a fraction of that.

On inflammation, several markers moved in the right direction but not far enough to count. Fresh sauerkraut lowered hsCRP, a common blood test for inflammation, by 13% on average and IL-6 by about 10%. Neither change was statistically significant. Pasteurized sauerkraut did slightly better on blood sugar, again without reaching significance.

The gut results may be the most telling. A popular theory holds that fermented foods tighten a "leaky" gut lining, which then calms inflammation throughout the body. The team measured three markers of gut-barrier health. None of them changed.

Some groups did respond better than others. People under 50 saw significant drops in blood pressure and blood sugar after eating the pasteurized sauerkraut. People who already ate at least 30 grams of fiber a day saw their hsCRP fall after either version. Results like these deserve caution, though. Splitting a study into many subgroups raises the odds of a chance finding, and the researchers could not identify any clear group of "responders."

Most volunteers handled a daily serving without trouble. About 70% reported no bloating or stomach upset, and roughly a third said they felt better, mentioning easier digestion or feeling less hungry.

Do fermented foods reduce inflammation? What other research shows

The Freiburg findings sit awkwardly beside one of the most cited studies in the field. In 2021, Stanford researchers had 36 healthy adults eat a diet heavy in fermented foods for 10 weeks.Levels of 19 inflammatory proteins in their blood dropped, IL-6 among them, while a comparison group on a high-fiber diet saw no such change.

The difference may come down to how much people ate. The Stanford volunteers worked up to about six servings a day of yogurt, kefir, kimchi, kombucha and other fermented foods. The Freiburg volunteers ate one side dish of one food.

Other studies are just as mixed. A 2011 Korean trial in overweight adults found thatfermented kimchi improved blood pressure and blood sugarmore than fresh, unfermented kimchi. A 2022 pilot study in which 31 women ate sauerkraut daily for six weeks found no effect on inflammation.

The blood pressure evidence is somewhat firmer. A 2013 analysis pooling 14 trials of probiotic fermented milk foundan average systolic drop of about 3 mmHg, slightly larger in people who already had high blood pressure. A bigger 2020 analysis of 24 trials founda similar effect that fell just short of significance. A 2025 review of kefir trials foundno effect on blood pressure or CRP.

The finding about pasteurized sauerkraut has a precedent, too. A 2018 study of people with irritable bowel syndrome, cited by the Freiburg team, found that fresh and pasteurized sauerkraut eased symptoms equally well. That suggests other ingredients, such as fiber, organic acids and plant compounds, do some of the work that is often credited to live bacteria.

Study limitations: salt, dose and who was tested

The study has limits worth knowing before you stock up. The sauerkraut it used was fairly mild, at 0.8% to 1.2% salt. Many supermarket brands are saltier: canned sauerkraut hasabout 659 mg of sodium per 100 grams, close to 30% of the recommended daily limit. That much salt could easily cancel out a 2-point drop in blood pressure, especially for people who are sensitive to it.

The fresh sauerkraut also held far fewer live bacteria than the roughly one billion per serving often cited as the threshold for a probiotic effect. And the volunteers were healthy, health-conscious people with little inflammation to begin with. People with obesity, diabetes or gut disease, who may have the most to gain, were not included.

Four weeks is also short for a diet study. Participants knew which sauerkraut they were eating, and they weighed and ate it at home without supervision. Inflammation wasn't even the trial's main focus; it was designed mainly to study gut bacteria.

How to eat fermented foods for your health

So should you eat more sauerkraut? If you enjoy it, there's no reason not to. Just think of it as a good food rather than a remedy.

If blood pressure is your concern, the cheaper jarred or canned kind seems to work as well as refrigerated "live" sauerkraut. Check the label for sodium, pick a lower-salt brand, and drain or rinse it if you need to.

If inflammation is your concern, sauerkraut alone probably won't do much. The better-supported approach is a diet rich in fiber from beans, whole grains, vegetables and fruit, with a variety of fermented foods added on top. If you want to eat more fermented foods, build up gradually to avoid bloating.

None of this replaces medical care. Sauerkraut is no substitute for blood pressure or diabetes medication, and anyone with a health condition should talk to their doctor before making big changes to their diet.

Frequently asked questions

Does sauerkraut reduce inflammation?

Not reliably in healthy people. In a 2026 trial of 87 adults, eating 100 g of sauerkraut a day for four weeks did not significantly lower IL-6, hsCRP or other inflammation markers. Diets with much more, and more varied, fermented food have shown reductions.

Does sauerkraut lower blood pressure?

Slightly. Systolic blood pressure fell by about 1.5 to 2.5 mmHg after four weeks of daily sauerkraut. Fresh and pasteurized versions worked equally well. Choose a lower-sodium product so the salt doesn't cancel the benefit.

Is pasteurized sauerkraut still healthy?

Yes. Pasteurized sauerkraut has no live bacteria but still contains fiber, vitamin C and organic acids. In the trial it matched fresh sauerkraut on blood pressure and showed slightly larger, though not significant, drops in blood sugar.

How much sauerkraut should I eat a day?

No ideal amount has been proven. The trial used 100 g a day, about half a cup, and most people tolerated it well. Start smaller if you are new to fermented foods, and keep an eye on total daily sodium.

Can sauerkraut heal a leaky gut?

There is no evidence for that in healthy people. The trial measured three gut-barrier markers (zonulin, FABP-2 and LBP) and found no change with either fresh or pasteurized sauerkraut.

Is sauerkraut high in sodium?

Often, yes. Typical canned sauerkraut has about 659 mg of sodium per 100 g, nearly 30% of the daily limit. Draining or rinsing it and choosing low-sodium brands cuts the amount.

Bottom line

A daily serving of sauerkraut is a safe, low-calorie habit that may lower blood pressure slightly, live bacteria or not. Whether it can meaningfully reduce inflammation, particularly in people who already live with chronic conditions, is still an open question.

Sources

• Schropp N, Bauer A, Stanislas V, Michels KB.Fermented foods and inflammation: a crossover intervention trial with fresh and pasteurized sauerkraut. European Journal of Clinical Nutrition, 2026;80:928–935.
• Study: Diet rich in fermented foods boosts microbial diversity, decreases inflammation(on Wastyk et al., Cell, 2021).
• Effect of probiotic fermented milk on blood pressure: a meta-analysis, British Journal of Nutrition, 2013.
• Probiotic fermented milk and blood pressure: systematic review and meta-analysis, International Journal of Food Properties, 2020.
• Kefir consumption, blood pressure and C-reactive protein: meta-analysis, 2025.
• Fermented kimchi reduces body weight and improves metabolic parameters, Nutrition Research, 2011.
• Sauerkraut nutrition facts (USDA-based)andSauerkraut and sodium.

This article is for general information and is not medical advice.