Abstract
Of 1667 subjects that attended the hospital, 1335 were patients with diagnosed medical conditions, together with 202 randomly selected, apparently healthy controls from the same population, were studied in detail for demographic variables, dietary and biochemical data. Dietary consumption of antioxidant vitamins A, E, and C and β-carotene and soluble fibre was lower in the majority of conditions compared to controls. Plasma concentrations of vitamin C and β-carotene were significantly lower in all patient groups. Reduced vitamin E levels were noted in patients with cardiovascular diseases, stroke, Parkinson's disease, chronic renal failure, nephrotic syndrome, type A behaviour, post-partum psychosis, burns, liver diseases, cancer, rheumatoid arthritis and aluminium phosphide poisoning. Lipid peroxides (thiobarbituric acid reactive substances), which are an indicator of oxygen-derived free radical damage, were significantly higher than controls in most conditions and marginally higher in respiratory and psychiatric conditions. Lipid peroxides levels were much greater over all in acute myocardial infarction, cancer, stroke, nephrotic syndrome, chronic renal failure, liver diseases, post-partum psychosis, pregnancy, burns and aluminium phosphide poisoning. Poor dietary intake alone does not explain the decreases in plasma levels of antioxidants and increases in lipid peroxides. Decreases may also be due to increased demands for antioxidants to counter free radical damage.