Dietary and blood antioxidants in patients with chronic heart failure. Insights into the potential importance of selenium in heart failure.

BACKGROUND: Chronic heart failure (CHF) seems to be associated with increased oxidative stress. However, the hypothesis that antioxidant nutrients may contribute to the clinical severity of the disease has never been investigated. AIMS: To examine whether antioxidant nutrients influence the exercise capacity and left ventricular function in patients with CHF.
METHODS: Dietary intake and blood levels of major antioxidant nutrients were evaluated in 21 consecutive CHF patients and in healthy age- and sex-matched controls. Two indexes of the severity of CHF, peak exercise oxygen consumption (peak VO2) and left ventricular ejection fraction (LVEF), were measured and their relations with antioxidants were analysed.
RESULTS: Whereas plasma alpha-tocopherol and retinol were in the normal range, vitamin C (P=0.005) and beta-carotene (P=0.01) were lower in CHF. However, there was no significant association between vitamins and either peak VO2 or LVEF. Dietary intake (P<0.05) and blood levels of selenium (P<0.0005) were lower in CHF. Peak VO2 (but not LVEF) was strongly correlated with blood selenium: r=0.76 by univariate analysis (polynomial regression) and r=0.87 (P<0.0005) after adjustment for age, sex and LVEF.
CONCLUSIONS: Antioxidant defences are altered in patients with CHF. Selenium may play a role in the clinical severity of the disease, rather than in the degree of left ventricular dysfunction. Further studies are warranted to confirm the data in a large sample size and to investigate the mechanisms by which selenium and other antioxidant nutrients are involved in CHF.