Both Mediterranean and AHA-Recommended Diets Reduce Events Post-MI

Shelley Wood

March 30, 2007

March 30, 2007 (New Orleans, LA) - High-risk patients who have survived a first MI can reduce their risk of subsequent cardiovascular events by eating either a Mediterranean-style diet or the low-fat diet recommended by the AHA, with no differences in risk reduction between the two diets, new research suggests.

The findings run counter to other recent diet studies that have suggested that the Mediterranean diet, with an emphasis on foods and oils rich in omega-3 fatty acids, may improve risk-factor profiles and be superior to an approach that indiscriminately reduces fat and, in tandem, increases carbohydrate consumption. Dr Katherine E Tuttle (Providence Medical Research Center, Spokane, WA) presented the results of the late-breaking study earlier this week at the American College of Cardiology 2007 Scientific Sessions. She says the findings should provide more options for people who simply don't like to eat the signature foods of the Mediterranean diet, namely lots of fish and plant-based proteins.

"The good news is there is more than one heart-healthy diet. You can offer choices for different groups of people in the community," she told heart wire .

Tuttle et al's study randomized 101 patients to either the AHA's step II diet (n=50) or a Mediterranean-style diet (n=51), with randomization occurring within six weeks of patients' index MIs. In both dietary interventions, patients received individual counseling sessions with a dietician--two sessions within the first month, then again at months 3, 6, 18, and 24--as well as six or more group counseling sessions. Both diets recommended limiting cholesterol consumption to <200 mg/day and saturated fats to <7% total calories; the Mediterranean diet, however, recommended much higher percentages of monounsaturated fats and omega-3 fatty acids and a reduced consumption of carbohydrates. Outcomes in the two intervention arms were then compared with 101 patients in a matched "usual-care" group who had received standard advice, when first hospitalized for their MI, on the benefits of a low-fat diet.

Both diets better than usual care

After a median of 46 months of follow-up (ranging from 18 to 72 months), Tuttle and colleagues found no differences in rates of death, MI, unstable angina, stroke, or hospital admission for congestive heart failure (CHF) between the AHA- and Mediterranean-diet groups. Strikingly, however, people randomized to either diet were significantly more likely than people in the usual-care group to avoid these events over the follow-up period. A total of eight events occurred in each of the dietary-intervention groups, none of them deaths; by contrast, 40 events occurred in the usual-care group, of which seven were deaths. Strokes also occurred significantly more often in the usual-care group.

Outcomes according to diet
End point Mediterranean diet AHA step II diet Usual care p*
Cardiac death 0 0 3 0.081
All deaths 0 0 7 0.007
MI 1 3 8 0.234
CHF admissions 0 0 3 0.081
Unstable angina 4 4 20 0.015
Stroke 3 1 2 0.407
Total events 8 8 40 <0.001<
*Usual-care group vs combined dietary-intervention groups

The AHA and Mediterranean diets also produced significant improvements in HDL and triglyceride levels over 24 months of follow-up, although with trends toward increased LDL-cholesterol, as compared with baseline levels; changes, however, were no different between the two groups.

HDL, LDL, and triglyceride levels at baseline and 24 months
Parameter
Baseline
24 mo
p*
HDL (mg/dL)


<0.001
Mediterranean
38 +7
40 +8

AHA
36 +9
40 +12

Triglyceride (mg/dL)


0.003
Mediterranean
143 +71
128 +67

AHA
183 +196
127 +75
LDL (mg/dL)


0.051
Mediterranean
93 +28
101 +27

AHA
93 +32
98 +23

*Baseline vs 24-month follow-up

"AHA step II and Mediterranean-style dietary interventions had similar benefits on cardiovascular outcomes and risk factors after MI," Tuttle concluded.

Intensity of intervention, not type, may be key

The equivalent findings were well received by trial participants, Tuttle noted during the discussion following her formal presentation of the trial results. "One of the things that our dieticians regularly reported was that for the people in this study--these were American, older, white patients in the Northwest--a lot of these patients . . . actually had trouble increasing their intake of olive oil and fish. They did it, but they were relieved by these results, because they preferred the low-fat diet," she said.

One of the session moderators, Dr Paul Ridker (Brigham and Women's Hospital, Boston, MA), pointed out that the most "compelling" finding may not be the equivalent findings between the two intervention groups but the difference between the intervention and usual-care groups, underscoring the importance of healthcare provider support for dietary interventions.

It's a point echoed by Tuttle, who told heart wire that the study, more than anything, shows the value of providing more intensive support for people who are trying to make significant dietary and lifestyle changes, regardless of the type of diet. In this study, participants were only required to attend the group counseling sessions six times over the 24 months but were encouraged to attend monthly classes if desired. Many took advantage of these extra classes, said Tuttle, not only to have the support of the dieticians and counselors but also for the encouragement of fellow study participants.

Commenting on the study for heart wire , Dr Sidney Smith (University of North Carolina, Chapel Hill) said, "I think the most important message from this study is that diets based on a reduced intake of cholesterol and saturated fats can have an impact on top of optimal medical therapy."

But Smith, too, singled out the value of intensive, ongoing support for dietary changes. "This study points to the importance of including counseling for diet as part of patient-discharge routines. This is one of the things we've fought for, reimbursement for diet, smoking-cessation, and exercise counseling, and this story really speaks to the impact of that kind of counseling."

The complete contents of Heart wire , a professional news service of WebMD, can be found at www.theheart.org, a Web site for cardiovascular healthcare professionals.


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