Kefir has antimutagenic and antioxidant properties, and can possibly be used to prevent mutagenic and oxidative damage in the human body. One can change the nutrient content by simply fermenting for shorter or longer periods. Both stages have different health benefits. For instance, kefir over-ripened (which increases the sour taste) significantly increases folic acid content. Kefir also aids in lactose digestion as a catalyst. The kefiran in kefir has been shown to suppress an increase in blood pressure and reduce serum cholesterol levels in rats. This does not necessarily imply the same for humans.