Mediterranean diets are better for the heart than low-fat diets, say researchers

07 Dec 2020 --- Following a traditional Mediterranean diet reduces the risk of secondary heart attacks in coronary heart disease (CHD) patients more effectively than standard low-fat diets, Spanish researchers have found. 

The findings build on a wealth of research into the benefits of a Mediterranean-style diet, particularly in combating the onset of cardiovascular diseases. However, this is the first time that the effects of Mediterranean diets have been tested on people already diagnosed with CHD.

The “Coronary Diet Intervention with Olive Oil, and Cardiovascular Prevention Study” (CARDIOPREV) is an ongoing research project controlling the diets of over 1,000 CHD patients in Spain. 

The current findings come as part of the project and analyzed the endothelial functions – one of the main predictors of cardiovascular incidents – of the participants over one year. 

“We observed that the Mediterranean diet model induced better endothelial function, meaning that the arteries were more flexible in adapting to different situations in which greater blood flow is required,” explains José López Miranda, one of the study authors. 

“The endothelium’s ability to regenerate was better, and we also detected a drastic reduction in damage to the endothelium, even in patients at severe risk.”

Mediterranean diets have been shown to improve biological predictors of heart attacks in CHD patients for the first time. Mediterranean trumps low-fat 
During the study, half of the participants were told to follow a Mediterranean diet, based on a high quantity of virgin olive oil, eating fruit and vegetables every day, and having three servings of legumes, fish and nuts per week. 

In addition, they were told to reduce meat consumption, particularly red meat, and avoid additional fats such as margarine and butter and any food high in sugar.

In contrast, the other half was told to follow a low-fat diet, based on limiting all kinds of fat –  animal and plant –  and increasing their intake of complex carbohydrates. 

They were also told to cut down on red meat, choose low-fat dairy products, avoid eating nuts, and reduce their intake of sweets and pastries.

Three central markers of cardiovascular health were then assessed in each group comparatively. 

Firstly, the vasodilation capacity in the patients’ arteries was analyzed. This capacity is essential in adjusting to different circumstances such as stress and exercise.  

Secondly, the degree of permanent endothelium damage was assessed. 

Lastly, the arteries’ reparation ability by means of endothelial progenitor cells, or stem cells, was measured.

All three of these markers were significantly improved by the Mediterranean diet compared with the low-fat diet, say the researchers. 

Taking Mediterranean diets to heart 
Miranda emphasizes the importance of the findings and their implications for CHD patients. 

“The degree of endothelial damage predicts the occurrence of future cardiovascular events, as in acute myocardial infarctions. If we can take action at the initial stages, prompting endothelium regeneration and better endothelial function, we can help to prevent heart attacks and heart disease from recurring,” she says. 

The research was conducted at the University of Córdoba, Queen Sofia University Hospital and the Maimonides Biomedical Research Institute of Cordoba (IMIBIC) and was published in PLOS Medicine. 

CARDIOPREV began in 2016 and is intended to run for a total of seven years. 

Beating diabetes and preventing overeating
Last month, researchers at Brigham Women’s Hospital uncovered biomarkers linking the Mediterranean diet to a reduced risk of type 2 diabetes (T2D). In a study of 25,000 women spanning 25 years, insulin resistance was proven to be the primary biological benefit of the diet, helping reduce the incidence of T2D. 

In 2019, a preclinical trial also found the diet could prevent overeating. At Wake Forest School of Medicine, US, scientists found that nonhuman primates on a Mediterranean diet chose not to eat all the food available to them and maintained an average weight.

Edited by Louis Gore-Langton

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