Why does sauerkraut need to be refrigerated for gut health?
Refrigerated, unpasteurized sauerkraut retains its live lactic acid bacteria, while pasteurized shelf-stable versions do not -- and that distinction genuinely determines whether the studied gut-health benefit is present.
The short answer
Sauerkraut is one of only four fermented foods with dedicated human RCT research (alongside kefir, natto, and sourdough), but the refrigerated-versus-shelf-stable distinction is not a minor detail -- it genuinely determines whether the studied benefit applies. Traditional lacto-fermentation produces live, active cultures that pasteurization destroys, and a 2025 pilot follow-up study in athletes using pasteurized sauerkraut did not replicate an earlier study's short-term microbiome diversity findings. Homemade or refrigerated raw sauerkraut is a genuinely accessible way to get the live-culture version.