It is a source of vitamins B, C, and K;[20] the fermentation process increases the bioavailability of nutrients rendering sauerkraut even more nutritious than the original cabbage.[21] It is also low in calories and high in calcium and magnesium, and it is a very good source of dietary fiber, folate, iron, potassium, copper and manganese.[20] If unpasteurized and uncooked, sauerkraut also contains live lactobacilli and beneficial microbes and is rich in enzymes. The fiber and supply of probiotics improve digestion and promote the growth of healthy bowel flora, protecting against many diseases of the digestive tract.[21][22]