Dietary Cysteine and Other Amino Acids and Stroke Incidence in Women

Background and Purpose-Cysteine could potentially lower the risk of stroke through antihypertensive and antioxidant effects. Our aim was to evaluate the hypothesis that cysteine intake is inversely associated with stroke incidence. Methods-We used data from the Swedish Mammography Cohort, a population-based prospective cohort of 34 250 women who were free of cardiovascular disease and cancer and had completed a food-frequency questionnaire about diet and other risk factors for stroke in the autumn of 1997. Stroke cases were identified by linkage of the study population with the Swedish Inpatient Register and the Swedish Cause of Death Register. Relative risks (RR) with 95% confidence intervals, adjusted for potential confounders, were estimated by using Cox proportional hazards regression model. Results-We ascertained 1751 incident cases of stroke during 10.4 years of follow-up. Dietary cysteine intake (mean, 635 mg/d) was inversely associated with stroke risk. The multivariable RR of total stroke comparing the highest with the lowest quintile of cysteine intake was 0.79 (95% confidence interval, 0.65-0.97; P for trend=0.04). The corresponding RR was 0.82 (95% confidence interval, 0.65-1.03; P for trend=0.12) for cerebral infarction and 0.54 (95% confidence interval, 0.29-1.03; P for trend=0.08) for intracerebral hemorrhage. Dietary intake of other amino acids showed no independent (after adjustment for cysteine intake) association with stroke risk. Conclusions-These findings suggest that dietary cysteine intake may be inversely associated with risk of stroke.