October 10, 2025, 6:02 pm | Read time: 4 minutes
It’s the German counterpart to Korean kimchi: sauerkraut. The fermented cabbage is experiencing a real comeback, especially among health-conscious individuals. No wonder–it’s considered a natural immune booster and is said to aid digestion. FITBOOK’s nutrition expert examines whether sauerkraut is truly as healthy as claimed.
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How Is Sauerkraut Prepared?
Sauerkraut is made through the fermentation of finely chopped cabbage. This is a natural fermentation process where lactic acid bacteria convert the sugar in the cabbage into lactic acid. These bacteria already live on the surface of fresh cabbage and are activated by salt. The salt draws water out of the cabbage and creates an oxygen-poor environment where beneficial lactic acid bacteria can multiply while harmful microorganisms are inhibited. This results in lactic acid, which preserves the vegetable, gives it its typical sour taste, and makes it particularly digestible.
To make it, you only need cabbage and salt, optionally enhanced with spices such as caraway or bay leaves. The finely shredded cabbage is tightly packed into jars and covered with liquid. Fermentation begins at room temperature, visible through bubbles. After about a week, the sauerkraut is ready to eat, though it continues to ferment during storage.
If you want to get creative or don’t like cabbage, you can also ferment carrots, radish, radishes, beets, or celery.
Stay Fit Through Winter–What Nutrients Are in Sauerkraut?
Sauerkraut is a winter classic because it remains preserved for a long time thanks to fermentation, and the lactic acid bacteria promote a healthy gut–which is known to house a large portion of our immune cells. In the middle of flu season, it’s particularly beneficial to regularly eat sauerkraut and other fermented products. It also has a distinct advantage for the gut: Unlike fresh cabbage, fermented kraut avoids bloating and gas.
Also interesting: 3 simple tips to avoid gas from legumes
Additionally, it contains significant amounts of vitamin C, which helps fend off infections. Just 100 grams of sauerkraut cover about 22 percent of the daily vitamin C requirement. A portion also meets 33 percent of the vitamin K requirement (important for our bones). While the kraut contains numerous other vitamins and minerals, such as calcium and magnesium, they are present in smaller amounts.1
Nutrients per 100 Grams at a Glance
- Energy: approx. 21 calories
- Protein: 1.5 grams
- Fat: 0.3 grams
- Carbohydrates: 0.8 grams
- Fiber: 2.1 grams
- Vitamin C: 20 milligrams
- Vitamin K: 25 micrograms
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Caution with Histamine Intolerance
Histamine intolerance means the body cannot properly break down ingested histamine–a natural messenger found in many foods. As a result, histamine can accumulate in the body and cause symptoms such as skin redness, headaches, gastrointestinal issues, or respiratory irritations. Since more histamine is produced during the fermentation of sauerkraut, you should–in consultation with your doctor or a nutritionist–eat only small amounts of sauerkraut or avoid it altogether.
Can Sauerkraut Contribute to Vitamin B12 Supply for Vegetarians and Vegans?
Vitamin B12 is produced exclusively by certain microorganisms and primarily enters the food chain through animal products. These contain the vitamin in a form usable by humans and in sufficient quantities.2
Since sauerkraut is produced through bacterial fermentation, it can indeed contain vitamin B12, but only in trace amounts. Furthermore, these are specifically vitamin B12 analogs. They are chemically similar to the original but lack biological effectiveness in the body. On the contrary, they can even hinder the absorption of the real vitamin by blocking transport systems.
In short, sauerkraut (and other plant-based foods) cannot meet the daily requirement of about four micrograms of vitamin B12 for adults. Vegetarians should therefore regularly consume dairy products and eggs. Vegans, on the other hand, must consistently take a vitamin B12 supplement to prevent deficiencies such as anemia or fatigue.