Mediterranean dietary pattern has been associated with lower cardiovascular (CV) mortality. People with heart disease have a lower risk of heart attack and strokes if they eat a Mediterranean-style diet.
After recruiting more than 15,000 people with heart disease from 39 countries, researchers scored their diets for Mediterranean elements such as eating plenty of whole grains, fruits, vegetables, legumes, fish, some alcohol, and some meat. They also scored diets for Western diet elements, such as consumption of refined grains, sweets and desserts, sugared drinks, and deep-fried foods.
After an average of 3.7 years, death, non-fatal heart attack or stroke occurred in 7.3% of people with a Mediterranean score of 15 or more – about 3% less than those scoring 14 or below (around 10%).
Surprisingly for some, higher Western diet scores did not increase the risk of these same problems.
The findings related to a very specific group: adults with stable coronary heart disease (CHD) who were at high risk of having a major cardiovascular event. This means the 3% reduction is not generalisable to the wider population, or even to all people with heart disease.
Although heart disease cannot be cured, treatment and lifestyle changes can help manage the symptoms and reduce the risk of further complications.
Some of the reporting promotes the line that “eating good food is more important than avoiding bad food”.
The study was carried out by researchers from universities in the US, New Zealand, Sweden, France, Denmark and Canada, and was funded by pharmaceutical manufacturer GlaxoSmithKline.
The study analysed data from adults with stable CHD and a high risk of a major cardiovascular event already recruited to a study, called the STABILITY trial. This was designed to test whether a new drug called Darapladib (not currently licensed in the UK) would prevent major cardiovascular events in this high-risk group. Some of the group were taking Darapladib, while others were taking a placebo.
From the STABILITY trial, the researchers used self-reported lifestyle data from 15,482 people from 39 countries to score each for “Mediterranean diet” elements, like eating plenty of whole grains, fruits, vegetables, legumes, fish, alcohol and some meat. They then scored them for “Western diet” elements, such as consumption of refined grains, sweets and desserts, sugared drinks, and deep-fried foods. People were asked to recall both the type and frequency of food during “a typical week”.
They then compared the numbers of major cardiovascular events – defined as death, non-fatal heart attack or non-fatal stroke – over the next three years (median 3.7 years) in those with greater Mediterranean or Western diet scores, to see if they were protective or harmful.
The analysis took account of many confounding factors known to affect risk of major cardiovascular events, including:
- treatment with Darapladib or placebo
- smoking history
- CHD severity
- cardiovascular disease risk factors (diabetes, HDL-cholesterol, history of high blood pressure)
- LDL – “bad” – cholesterol
- body mass index (BMI)
- self-reported physical activity
- geographic region
- level of education
The Mediterranean and Western diet scores were totalled and categories defined. For example, most people (56%) scored 12 or less for Mediterranean score, a quarter scored 13 to 14 (26%) and a minority scored 15 or over (18%). Despite the differences in Mediterranean score, Western diet scores were around 12 across all three groups.
This study showed 3% fewer people with CHD, at high risk of major cardiovascular events, who reported eating the healthiest Mediterranean-style diets, had either died, or had a non-fatal heart attack or stroke over a three-year period than those with less healthy diets. Western diet scores were not related to major cardiovascular events.
The study was large, worldwide and its methods quite robust, all boosting the believability of the findings.
Credit: U.S. National Library of Medicine & National Center For BioTechnology Information