Sauerkraut can only be eaten occasionally. If you overeat for a long time, it may cause urinary calculi. In addition, vitamin C was destroyed a lot in the pickling process of sauerkraut. If the human body lacks vitamins, it will reduce the ability to inhibit the deposition of calcium oxalate crystals in the kidney and reduce the formation of stones. Eating pickled cabbage with too much nitrite will turn hemoglobin in the blood into methemoglobin, which will make red blood cells lose their oxygen-carrying ability and lead to tissue hypoxia.