Plasma Total Antioxidant Capacity in an Adult Hong Kong Chinese Population

Objectives: To examine plasma total antioxidant capacity (TAOC) in a Chinese population with a lower incidence of cardiovascular disease compared with Caucasian populations, in relation to dietary intake, age, sex, and the presence of cardiovascular diseases. Design and methods: As part of a randomized territory-wide survey stratified by sex and 10-year age groups; 728 subjects (367 men, 361 women) were recruited. Dietary intake assessment was by a food frequency questionnaire; plasma TAOC was estimated by the ABTS method. Results: The TAOC values were normally distributed, the mean ± SD being 1.78 ± 0.18 mmol/L. The mean value was higher in men compared with women, inspite of a lower dietary intake of vitamins A and C per 1000 kcal in the former. Subjects who consumed water spinach twice or more a week had higher mean levels. No difference in mean levels was observed between those with and without hypertension or cardiovascular disease. Conclusion: Measurement of plasma TAOC as a risk factor in epidemiological studies of cardiovascular diseases may have limited use, since TAOC include substances associated with a protective effect as well as increased risk.