This is not a popular soup in Poland nowadays, but this is a soup my grandma was cooking years ago. Her roots were in Eastern Poland, she was born on the area, which after a II Worlds War has become a Belarus territory.
Sauerkraut salad is a great immune support during autumn and winter, is a source of vitamins and probiotics. It makes good job for your intestines and your skin condition. You can eat it when you are on diet or just want to stay healthy.
Remember to buy sauerkraut from trusted seller, as it can be cheated and added vinegar instead of traditional longer procedure of fermentation.