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Abstract

The aging process is an universal phenomenon. The causes of aging or the mechanisms determining the life span potential is till now dissatisfying, due to a plenty theories:
programmed aging, error catastrophe theory and free radical theory are the most widely to be discussed. The evidence that food restriction in rats, Ipice, and hamsters retards the aging processes is summarized and ineludes its ability to extend the maximum life span, to decrease the rate of increase in age-specific mortality. The incidence of other diseases
frequently gallstones, renal stones, and cancers of breast, ovary, and prostate, al so has risen sharply in this century, specially in more prosperous areas. The free radicals theory of aging is basically found on observations as natural defense or control mechanisms ocurr, both enzymatic (superoxide dismutase, catalase, glutathione peroxidase) or chemical (antioxidants such as vitamin E, vitamin C, glutathion). Responsability of free radicals in aging has probably to be shared with other mechanisms, among genetic control, inmunological deficiency, metabolic deviation. The Maillard reaction and its key role in the development of age-related pathologies are discussed. Advanced products accumulate on long-lived proteins, such as collagen, lens cristallins and myelin. They are responsibly for intra-and inter-protein crosslinkings wbich deeply disturb the structure and function of tissues, as it occurs in cataract atheroselerosis. The lowering of serum cholesterol concentrations in subjects by diet, drugs, or both leads to a decrease in coronary heart disease have also reported an increase in deaths due to suicide or violence. A reduction in serum cholesterol, lower the lipid rnicroviscosity, and decrease the exposure of protein receptors on the membrane surface, resulting in a poorer uptake of serotonin from the blood. Patients who had attempted suicide had significantly lower cerebrospinal fluid levels of metabolite 5-hydroxyindolacetic than
those who had not.