Scientists isolated vitamin E from wheat germ oil in the 1920s and called it the "antisterility" vitamin. Its name, alpha-tocopherol, is from the Greektokos, "offspring" andphero, which means "to bear". Vitamin E is an antioxidant, protecting cell membranes from free radical damage. , , This activity helps block the formation of compounds that can increase risk for atherosclerosis. Vitamin E Natural Source from Webber Naturals offers naturally sourced vitamin E (d-alpha tocopheryl acetate), a form which is almost twice as bioavailable as synthetic vitamin E. This natural form of vitamin E is extracted by cold-pressing methods that do not damage the tocopherols. , , Vitamin E protects cell membranes from compounds such as lead, mercury, and other heavy metals; toxic compounds such as cleaning solvents; drugs, radiation, and the body's free-radical metabolites. Severe vitamin E deficiency is quite rare, but symptoms in adults could include nerve damage, muscle weakness, poor coordination, involuntary movement of the eyes, and breaking of red blood cells, leading to hemolytic anaemia.