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Therapeutics

A Mediterranean-type diet reduced mortality in patients with a first MI

ACP J Club. 1998 Nov-Dec; 129:61. doi:10.7326/ACPJC-1998-129-3-061


Source Citation

de Lorgeril M, Salen P, Martin JL, et al. Mediterranean dietary pattern in a randomized trial: prolonged survival and possible reduced cancer rate. Arch Intern Med. 1998 Jun 8;158:1181-7.


Abstract

Question

In patients who have had a first myocardial infarction (MI), does a Mediterranean-type diet (rich in α-linolenic acid) reduce death, subsequent MI, and cancer better than a diet similar to the American Heart Association (AHA)step 1 diet?

Design

Randomized controlled trial with a mean follow-up of approximately 4 years (Lyon Diet Heart Study).

Setting

A coronary care unit and follow-up program in Lyon, France.

Patients

605 patients {mean age 54 y, 91% men}* who had a first MI. {Exclusion criteria were severe heart failure, hypertension (> 180/110 mm Hg), inability to complete an exercise test, or other conditions thought to limit survival or participation}*.

Intervention

302 patients were allocated to a Mediterranean-type diet consisting of increased bread, cereals, fresh fruit and vegetables, legumes, and fish; moderate amounts of red wine at meals; decreased delicatessen foods and meat; no butter or cream (replaced by an experimental canola oil-based margarine rich in oleic and α-linolenic acids); and foods prepared with canola and olive oils. 303 patients allocated to the control group were to follow a diet similar to the step 1 AHA diet of 30% total energy from fats (10% saturated, 10% monounsaturated, and 10% polyunsaturated) and < 300 mg/d of cholesterol according to advice from their attending physician.

Main outcome measures

All-cause and cardiac mortality; incident cancer; combined all-cause mortality and nonfatal cancer; and combined all-cause mortality, nonfatal cancer, and MI.

Main results

Analysis was by intention to treat. After adjustment for sex, age, blood cholesterol level, leukocyte count, and aspirin use, patients allocated to the Mediterranean-type diet had a lower risk for all-cause mortality (relative risk [RR] 0.44, 95% CI 0.21 to 0.94); cardiac mortality (RR 0.35%, CI 0.15 to 0.83); combined all-cause mortality and nonfatal cancer (RR 0.44, CI 0.24 to 0.83); and combined all-cause mortality, nonfatal cancer, and nonfatal MI (RR 0.38,CI 0.23 to 0.61); and a trend toward a decreased risk for cancer (RR 0.39,CI 0.15 to 1.01).

Conclusions

After a first acute myocardial infarction, patients who followed a Mediterranean-type diet had reduced all-cause and cardiac mortality; combined all-cause mortality and nonfatal cancer; and combined all-cause mortality, nonfatal cancer, and myocardial infarction compared with those who followed an approximate American Heart Association step 1 diet. The Mediterranean-type diet also showed a trend toward a decreased risk for cancer.

Source of funding: Not stated.

For correspondence: Dr. M. de Lorgeril, Explorations Fonctionnelles Cardio-Respiratoires, CHU Nord de Saint-Etienne, Niveau 6, 42055 Saint-Etienne Cedex 2, France. FAX 33-4-7782-8461.

*de Lorgeril M, Renaud S, Mamelle N, et al. Lancet. 1994:343:1454-9.


Commentary

In a secondary coronary heart disease (CHD) prevention study, de Lorgeril and colleagues examined the effects of a Mediterranean-type diet on risk for new CHD, cancer events, and mortality. Compared with an approximate AHA step 1 diet, the intervention diet decreased the risk for new cancer, CHD death, and all-cause mortality. Both diets restricted total dietary fat to approximately 30% of calories but differed by type of fat consumed: The experimental diet was lower in saturated and omega-6 polyunsaturated fatty acids and higher in monounsaturated and omega-3 polyunsaturated fatty acids (largely provided by an experimental canola margarine). Because the intervention, which included periodic dietary counseling, also resulted in increased fiber, fruit, and vegetable consumption, differences in event rates cannot be ascribed solely to differences in dietary fat composition.

Although the "diet-heart" hypothesis rests on a substantial body of evidence, the case for the "diet-cancer" hypothesis is more tenuous. Regarding dietary fat consumption, some observational studies have reported an association between saturated fat and the risk for breast, colon, and prostate cancer (1). In laboratory animals, omega-6 polyunsaturated fatty acids (such as linoleic acid) promote tumor growth, whereas fish oils (which are rich in omega-3 polyunsaturated fatty acids) inhibit tumor growth (1). Human population studies, however, have not found a consistent association between dietary polyunsaturated fatty acids and cancer (1).

There is general agreement that healthy diets for adults should include adequate dietary fiber (20 to 35 g/d) and fruits and vegetables (≥ 5 servings/d), and should restrict saturated fat (≤ 10% of energy). Based on the Lyon Diet Heart Study, replacing saturated fat with monounsaturated fat (from olive or canola oil) or omega-3 polyunsaturated fat (from fish or plant sources) seems to be safe and may be beneficial.

Joel A. Simon, MD, MPH
San Francisco Veterans Affairs Medical CenterUniversity of California, San FranciscoSan Francisco, California, USA


Reference

1. National Research Council, Committee on Diet and Health. In: Diet and Health: Implications for Reducing Chronic Disease Risk. Washington, DC: National Academy Pr; 1989:5-6.