Current issues of ACP Journal Club are published in Annals of Internal Medicine


Therapeutics

Cardioprotective diet reduced mortality and complications after recent myocardial infarction

ACP J Club. 1992 Nov-Dec;117:76. doi:10.7326/ACPJC-1992-117-3-076


Source Citation

Singh RB, Rastogi SS, Verma R, et al. Randomised controlled trial of cardioprotective diet in patients with recent acute myocardial infarction: results of one year follow up. BMJ. 1992 Apr 18;304:1015-9.


Abstract

Objective

To ascertain if the addition of fruit, vegetables, dried legumes, nuts, and fish to a fat-reduced semi-vegetarian diet reduces mortality and complications in patients with a recent suspected myocardial infarction.

Design

Randomized controlled trial with 1-year follow-up.

Setting

Research hospital in India.

Patients

All hospitalized patients with a recent, suspected myocardial infarction or unstable angina pectoris were included. Exclusions were cancer, diarrhea, dysentery, blood urea > 400 mg/L, dislike of diet, and noncardiac chest pain. 406 patients were studied (mean age, 51 y; mean body mass index, 23.8; 365 men), and all were assessed and randomized within 48 hours of their cardiac event.

Intervention

Diets were based on American Heart Association recommendations and included replacement of meat, eggs, hydrogenated oils, and butter with vegetarian meat substitutes and soya bean, sunflower, and peanut oil. Patients in group A (n = 204) were advised to eat fruit and vegetables, at least 400 g/d, along with dried beans, split peas, lentils, nuts, and fish. Patients in group B (n = 202) received no additional instructions. All patients received advice on dietary-fat reduction, smoking, alcohol intake, stress management, and exercise. Follow-up after the first 7 weeks varied from every 1 to 12 weeks depending on severity of myocardial infarction. Physician assessors were blinded to diet status, analysis was by intention-to-treat, and 1-year follow-up was 83%.

Main outcome measures

Mortality; dietary intake and compliance and cardiac symptoms as assessed at clinic visits; a complete physical assessment done at 1 year.

Main results

At 1 year, patients in group A adhered to their diets better; had significantly lower total, low-density lipoprotein-, and high-density lipoprotein-cholesterol levels (P < 0.05 for all comparisons); and had lost more weight (6.3 kg vs 2.4 kg) than those in group B. Patients in group A also had fewer cardiac events (fatal and nonfatal myocardial infarction and sudden cardiac deaths) (50 vs 82, P < 0.001), lower total mortality (21 [25%] vs 38 [41%] deaths, P < 0.01), and lower total cardiac mortality (20 vs 34 deaths, P < 0.01). {This absolute risk reduction of 16% means that 6 patients would need to receive a cardioprotective diet (compared with a regular diet) to prevent 1 additional death, 95% CI 4 to 14; the relative risk reduction was 40%, CI 19% to 55%.}*

Conclusion

Comprehensive diet changes initiated within 48 hours of myocardial infarction were associated with weight loss, and reduced cholesterol levels, cardiac complications, and mortality.

Source of funding: No external funding.

For article reprint: Dr. R.B. Singh, Medical Hospital and Research Centre, Civil Lines, Moradabad-10, UP India.

*Numbers calculated from data in article.


Commentary

The study by Singh and colleagues shows clinical benefits in cardiac patients from dietary changes that focus on increasing the consumption of vegetables, fruits, cereals, dried legumes, lentils, nuts, and oil in conjunction with a weight-loss program. The surprising result was that important effects were obtained within 1 year with dietary interventions begun early after a cardiac event.

Both groups had baseline dietary intakes of less than 30% of their calories from fat and less than 11% of their calories from saturated fat. 36% of the participants were smokers at baseline, and the authors and their colleagues are to be congratulated for the 70% cessation maintenance at 1 year in both groups.

The mean age of the patients was 52 years, and I am surprised and impressed by the reduction of cardiac events and total mortality. These results seem unusual by North American standards. It is unclear if patients in both groups were comparable for severity of cardiac disease at randomization.

The goal of the intervention diet was to have 400 g/d of fruits and vegetables with increased fiber, vitamins A, C, and E, along with carotene and minerals. In the control group, fiber intake was approximately 25 g/d at 1-year follow-up compared with 52 g/d in the intervention group. These fiber intakes are much higher than in the average North American diet and, again, call attention to the importance of dietary fiber in cardiac risk management.

In summary, this study supports, but does not prove, the hypothesis that cardiac risk in cardiac patients can be reduced by weight loss and a high vegetable and fruit diet. As the commentator's cliché goes, "More studies are needed."

Stephen R. Yarnell, MD
University of WashingtonEdmonds, Washington, USA

Stephen R. Yarnell, MD
University of Washington
Edmonds, Washington, USA