In a recent study, scientists compared the effects of a Mediterranean diet with those of a low fat diet on key biological processes linked to heart health.
The researchers found that a Mediterranean diet could improve endothelial function in people with coronary heart disease.
The endothelium is a thin membrane that coats the inside of blood vessels and the heart. It plays a number of roles that are important for the functioning of the cardiovascular system.
The recent research, summarized in the journal PLOS Medicine, may help guide doctors giving nutritional advice to people with coronary heart disease.
As the Centers for Disease Control and Prevention (CDC) report, heart disease accounts for around 1 in 4 deaths in the United States, making it the leading cause of death.
Having high blood pressure, high cholesterol, or smoking increases the chances of developing heart disease, and having the disease increases the risk of cardiovascular events, such as heart attacks, arrhythmia, or heart failure.
Modifying the diet is a key way to reduce the risk of heart disease.
For many years, researchers have demonstrated the benefits of a Mediterranean diet on heart health. It includes olive oil, vegetables, nuts, legumes, fruits, and whole grains, with small amounts of dairy and meat and a moderate amount of fish and red wine.
Health experts, including the American Heart Association (AHA), have also linked low fat diets with improvements in heart health. This type of diet contains reduced amounts of all types of fat and increased amounts of complex carbohydrates.
The team behind the present study set out to test the effects of each type of diet on the endothelium because endothelial dysfunction is a predictor of cardiovascular disease.
According to Prof. José López-Miranda, the corresponding author of the study and coordinator of the Nutritional Genomics and Metabolic Syndrome research group at the Maimonides Biomedical Research Institute of Córdoba, in Spain:
“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 prevent heart attacks and heart disease from reoccurring.”
To determine the potential benefits of a Mediterranean diet compared with those of a low fat diet on endothelial dysfunction, the researchers analyzed data gathered as part of the Coronary Diet Intervention with Olive Oil and Cardiovascular Prevention study, an ongoing, single-blind randomized controlled study.
The study included 1,002 people with coronary heart disease who had not had a coronary event in the past 6 months.
The researchers used flow-mediated dilation to determine a baseline level of endothelial dysfunction among the participants. They then assigned the participants to two groups: One followed a Mediterranean diet for 1 year, and the other followed a low fat diet for 1 year.
At the end of the year, the team measured the participants’ endothelial function again. In total, 805 participants completed the study.
Compared with the low fat diet, the Mediterranean diet significantly improved the participants’ endothelial function — no matter how severe the dysfunction had been.
As Prof. López-Miranda explains, “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.”
In addition, the researcher noted, “The endothelium’s ability to regenerate was better, and we detected a drastic reduction in damage to the endothelium, even in patients at severe risk.”
The researchers also found that the Mediterranean diet resulted in improved levels of high-density lipoprotein cholesterol and reductions in fasting glucose and C-reactive protein among the participants, compared with the low fat diet.
They suggest that these factors may contribute to the beneficial impact of the Mediterranean diet on endothelial function.
The findings suggest that switching to a Mediterranean diet could help reduce the known risk of endothelial damage, coronary heart disease, and future coronary events.