Fermented foods and inflammation: a crossover intervention trial with fresh and pasteurized sauerkraut

Fermented foods have been proposed to beneficially affect glycemic control and the inflammatory state of the body, potentially by strengthening the gut barrier. However, scientific evidence for their health-promoting capabilities is scarce. We assessed the influence of the daily consumption of fresh and pasteurized sauerkraut on circulating "leaky gut" markers, inflammatory markers, blood pressure, and markers for glycemic control. Methods In this randomized crossover intervention trial, 87 healthy participants consumed 100 g/day of fresh and pasteurized sauerkraut for four weeks. Prior to each intervention phase, participants underwent a washout phase of four weeks' length during which no fermented foods were consumed. We used mixed regression models to compare assessed parameters before and after each intervention. Results Consumption of both fresh and pasteurized sauerkraut was associated with a small reduction in systolic blood pressure. Modest changes in selected markers of inflammation and glycemic control were observed following stratification by age, estimated daily fiber consumption, and to a lesser extent, BMI and sex. No change in gut barrier integrity was observed. Conclusions Live bacteria are not essential for the hypotensive potential of sauerkraut. Four weeks of daily consumption was not linked to an appreciable systemic health benefit in healthy individuals.