Effect of antioxidant-rich foods on plasma ascorbic acid, cardiac enzyme, and lipid peroxide levels in patients hospitalized with acute myocardial infarction.

OBJECTIVE

To determine whether a fat- and energy-reduced diet rich in antioxidant vitamins C and E, beta carotene, and soluble dietary fiber reduces free-radical stress and cardiac enzyme level and increases plasma ascorbic acid level 1 week after acute myocardial infarction.

DESIGN

Randomized, single blind, controlled study.

SETTING

Primary- and secondary-care research center for patients with myocardial infarction.

SUBJECTS

All subjects with suspected acute myocardial infarction (n = 505) were considered for entry to the study. Subjects with definite or possible acute myocardial infarction and unstable angina (according to World Health Organization criteria) were assigned to either an intervention diet (n = 204) or a control diet (n = 202) within 48 hours of symptoms of infarction.

INTERVENTIONS

Intervention and control groups were advised to consume a fat-reduced, oil-substituted diet. The intervention group was also advised to eat more fruits, vegetable soup, pulses, and crushed almonds and walnuts mixed with skim milk.

MAIN OUTCOME MEASURES

Reduction in plasma lipid peroxide and lactate dehydrogenase cardiac enzyme levels, increase in plasma ascorbic acid level, and compliance with diet, especially with vitamin C intake as determined by chemical analysis.

STATISTICAL ANALYSIS

A two-sample t test using one-way analysis of variance for comparison of data.

RESULTS

Plasma lipid peroxide level decreased significantly in the intervention group compared with the control group (0.59 pmol/L in the intervention group and 0.10 pmol/L in the control group; 95% confidence interval of difference = 0.19 to 0.83). Lactate dehydrogenase level increased less in the intervention group than in the control group (427.7 vs 561.2 U/L; confidence interval of difference = 82.9 to 184.7). Plasma ascorbic acid level increased more in the intervention group than in the control group (23.38 vs 7.95 mumol/L; confidence interval of difference = 12.85 to 26.13).

APPLICATIONS/CONCLUSIONS: Consumption of an antioxidant-rich diet may reduce the plasma levels of lipid peroxide and cardiac enzyme and increase the plasma level of ascorbic acid. Antioxidant-rich foods may reduce myocardial necrosis and reperfusion injury induced by oxygen free radicals.