JOHNS HOPKINS (US) — A so-called “Mediterranean diet” can improve heart health in people at risk for cardiovascular disease, even if dietary changes aren’t coupled with weight loss, a study shows.
Swapping out white bread and pasta carbohydrates for unsaturated fat from foods like avocados, olive oil, and nuts helps the body avoid insulin levels that could be triggers for diabetes and, eventually, heart disease, the study found.
“The introduction of the right kind of fat into a healthy diet is another tool to reduce the risk of future heart disease,” says Meghana Gadgil, a postdoctoral fellow in general internal medicine at Johns Hopkins University. She presented the research recently at the American Heart Association’s scientific sessions in Orlando
Gadgil and her colleagues analyzed data from the OmniHeart Trial, which studied the cardiovascular effects of three different balanced diets on 164 people with mild hypertension but no diabetes.
The researchers compared the body’s ability to regulate blood sugar and maintain healthy insulin levels while on a carbohydrate-rich diet, a protein-rich diet and a diet rich in unsaturated fats. People whose bodies fail to use insulin effectively usually develop type 2 diabetes, a major risk factor for heart disease.
The researchers found that a generally balanced diet higher in unsaturated fats such as those in avocados, olive oil and nuts improves insulin use significantly more than a diet high in carbohydrates, particularly such refined carbs as white bread and pasta. The preferred diet is very similar to the Mediterranean diet, inspired by the foods of southern Italy and Greece and emphasizing healthy fats, fruits and vegetables.
Each participant in the study was fed each of the three diets for six weeks in a row, with two to four weeks off in between. Blood samples were collected after fasting periods in weeks four and six of each diet, and used to monitor insulin and glucose levels. The study was designed to keep participants at their starting weights.
“A lot of studies have looked at how the body becomes better at using insulin when you lose weight,” Gadgil says. “We kept the weight stable so we could isolate the effects of the macronutrients. What we found is that you can begin to see a beneficial impact on heart health even before weight loss.”
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