AHA Step II and Mediterranean diets compared head-to-head in THIS-Diet

Both diets had similar effects on combined rates of death, repeat MI and unstable angina.

NEW ORLEANS — In a comparison trial, researchers found that the American Heart Association’s Step II diet and the Mediterranean diet are equally beneficial for people who have had a myocardial infarction.

“Survival free of the primary outcome, which was a composite of major adverse cardiovascular events after MI, did not differ between the AHA Step II and Mediterranean-style dietary intervention groups,” said Katherine R. Tuttle, MD, medical and scientific director for the Providence Medical Research Center, Sacred Heart Medical Center, Spokane, Wash., at the 56th Annual American College of Cardiology Scientific Sessions 2007.

The Heart Institute of Spokane Diet Intervention and Evaluation Trial (THIS-Diet) provided the comparator arm missing from previous epidemiological studies that have shown the Mediterranean diet and lifestyle is linked with lower rates of CVD.

Diet and lifestyle

Patients who had an MI six weeks prior to enrollment were randomly assigned either the AHA Step II (n=50) or Mediterranean diet (n=51). All participants met with a dietitian twice for individual counseling in the first month, then again at three, six, 12, 18 and 24 months. Participants also attended six or more group nutrition classes over two years.

Patients were advised to limit cholesterol intake to 200 mg daily and saturated fat intake to no more than 7% of calories.

Most of the participants were white men, average age 58 to 59. Fifteen percent to 20% had type 2 diabetes and approximately half had hypertension.

Virtually no difference

After an average of four years, there was no difference between the two diet groups in the combined rates of death, repeat MI, unstable angina, stroke or hospitalization for congestive heart failure (P=.807).

When researchers combined and compared the diet groups to a matched usual care group of 101 patients who did not receive the intensive dietary counseling post-MI, the relative risk of cardiovascular complications was reduced by two-thirds in the dietary intervention groups (OR= 0.33; 95% CI, 0.18-0.60).

Total BP was controlled in both the dietary intervention and usual care groups. From baseline, HDL increased 40±8 mg/dL at two years in the Mediterranean group and 40±8 mg/dL in the AHA Step II group (P<.001). Triglycerides improved from 143 mg/dL at baseline in the Mediterranean group to 128 mg/dL and in the AHA Step II group, went from 183 mg/dL to 127 mg/dL (P<.003).

“By and large, risk factors were well controlled and also did not differ by diet group despite greater omega fat intake in the Mediterranean-style group, and in particular, HDL increased and triglycerides decreased in both groups,” Tuttle said.

There was no general weight change in the study population because the researchers sought to measure the effect of omega-3 fatty acid intake and both diets’ effect on cardiovascular outcomes, not weight loss, Tuttle said.

“We conclude that in an active intervention trial, American Heart Association Step II and Mediterranean-style dietary intervention had similar benefits on cardiovascular outcomes and risk factors after myocardial infarction and that intervention with either an AHA Step II or a Mediterranean-style diet seems to be prudent in patients with high cardiovascular risk,” Tuttle said. “Longitudinal dietary intervention was [also] associated with improved outcomes compared with usual care.” – by Judith Rusk

For more information:

• Tuttle KR. American Heart Association or Mediterranean diet improves cardiovascular outcomes after myocardial infarction. Presented at: the 56th Annual American College of Cardiology Scientific Sessions 2007; March 25-27, 2007; New Orleans.