http://www.natur-leaf.com/sosonkin-testimonial.asp
large number of studies have looked at the effectiveness of sitosterols, which is the primary ingredient of the Natur-Leaf product that we have used in our medical practice since February 2000. Sitosterols raise superoxide dismutase (SOD) levels, which are basic to lifespan. These enzymes change the superoxide anion to hydrogen peroxides and then to water or water and oxygen. The SOD involved in the first step of the process against free-radical activity includes both antioxidant scavenging enzymes and free antioxidants such as vitamin C and vitamin E, which may be classified in the same category with sitosterols: