Israel Medical Association Journal

Although the free radical theory of aging is widely accepted among scientists, the possibility of using antioxidants to delay the aging processes seems to encounter considerable skeptism among clinicians. This may be, at least in part, due to lack of knowledge about the basic chemistry and biological behavior of oxidative stress, antioxidants, and the complex interactions between them. However, one cannot ignore the explosive growth of information concerning the mechanisms underlying the processes of aging, their consequences, and the use of antioxidants in suppressing such effects. In order to provide patients with the most accurate information regarding the use of antioxidant supplementation in their diet, it is important to obtain basic data regarding oxidative stress and antioxidants. This article explores the role of oxidative stress in the aging phenomena, recent evidence supporting supplementation of antioxidants for aged people,  the ability of antioxidants to prevent or retard cancer and atherosclerosis (the major causes of mortality in the aged population), and the ability of antioxidant supplementation to delay age-dependent deterioration of cognitive function. Based on the data presented, we conclude that current knowledge provides insufficient and inconclusive support for antioxidant supplementation as a means of delaying aging processes, despite the encouraging results obtained in many studies.

Background: Obesity is among the well-established risk factors for cardiovascular morbidity and mortality. However, the exact mechanisms are not well understood. Low concentrations of vitamins (fat soluble antioxidants and B vitamins) are linked to accelerated atherosclerosis through increased oxidative stress and homocysteine.

Objective: To compare plasma antioxidant vitamins (carotenoids and vitamin E), B vitamins (folic acid and B12) and homocysteine – all linked to increased cardiovascular morbidity – between patients with severe obesity and lean control subjects.

Methods: We investigated plasma carotenoids, vitamin E, folic acid, B12, and homocysteine in 25 obese patients and their age-matched controls (body mass index 38 ± 3 vs. 21 ± 2 kg/m²), respectively), related to BMI[1] and plasma insulin.

Results: Patients with obesity had normal B vitamins and a non-significant decrease in plasma homocysteine as compared to controls (9.4 ± 2.6 vs. 11.4 ± 4.8 mmol/L, P = 0.07). There was a significant decrease in both plasma carotenoids and vitamin E (0.69 ± 0.32 vs. 1.25 ± 0.72 and 24 ± 10 vs. 33 ± 14 mg/ml, respectively; P < 0.01). Both vitamins were inversely related to BMI and plasma insulin, which was significantly increased in patients with obesity (22 ± 21 vs. 6 ± 2 mU/ml, P < 0.01).

Conclusions: Obese patients with BMI above 35 kg/m² show low plasma antioxidants (carotenoids and vitamin E). This may result in increased oxidative stress and consequently enhanced atherosclerosis in these patients.

Methods: We attempted to investigate plasma oxidation and plasma and erythrocyte glutathione and glutathione enzymes in 20 patients with NIDDM, compared with euglycemic matched controls. Plasma oxidation was analyzed both basally (without) and as induced by 2,2'-azobis,2-amidopropane hydrochloride measured by the generation of thiobarbituric acid reactive substances and lipid peroxides.

Results: There was a significant increase in oxidation both basally (without) and as induced by AAPH. Plasma glutathione was lowered by 50% (P<0.01) and erythrocyte glutathione peroxidase, glutathione s-transferase and glutathione reductase activities were lower by 30%, 27% and 46%, respectively (P<0.01) in the patients with NIDDM.

Conclusions: Confronted by increased oxidation, patients with NIDDM show an abnormal plasma and erythrocyte antioxidative capacity, which may result in an accelerated rate of complications.

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NIDOM= non-insulin-dependent diabetes mellitus