Oxygen is necessary for human life. But oxygen has two aspects, one beneficial and one malign. The oxygen we breathe is conveyed to every part of the body where it plays a key role in metabolism. But it can also be a very harmful agent in the form of active or free radical oxygen. Active oxygen is a problem because it can combine with anything in the body and oxidize it with consequentdestruction of cell membranes, damageto DNA and oxidation of lipids (fats). All of these can lead to diseases like cancer. Here we shall focus on the process by which active oxygen combines with lipids (fats) in the body to create lipid peroxide, that is, lipid with an excessive amount of oxygen. Lipid peroxide is thought to be a harmful substance which can trigger the diseases such as cancer, cardio-vascular disease and diabetes. Since lipid peroxide is more easily generated and less easily purged as age advances, it tends to accumulate in the body. Lipofuscin, called the *aging pigment,, also accumulates in the body in proportion to age and is considered to be an index of aging. But lipofuscin is itself created by lipid peroxide, which suggests a connection between aging and lipid peroxide. One way to slow aging may, therefore, be to prevent the production and accumulation of active oxygen and lipid peroxide in the body. It has been shown, for example, that the higher the concentration of the powerful antioxidants vitamins E and C in the bodies of animals, the longer they live. This suggests that active consumption of agents that are effective antioxidants will restrain the aging process.
We already know that green tea is rich in those vitamins that possess this antioxidizing capability. In addition, Prof. Okuda(#12) has recently demonstrated that catechin in green tea is a far stronger antioxidant than vitamin E (about 20 times stronger in fact). These results come from laboratory tests only, and we must wait for further research to confirm a direct cause and effect relationship between the antioxidizing function of green tea and the retardation of aging. But the very fact that green tea contains a powerful antioxidant is a strong foundation for believing it can help control aging.

(#12)T.OKUDAet al.,Chem.Pharm.Bull.,31,1625(1983).