May 3 (UPI) -- People who consume a Mediterranean-type diet high in nutrients such as protein, zinc and vitamin B3 may see improvements in heart health, a study presented Tuesday found.
After one year on a weight-loss program that included personalized exercise plans, as well as nutrition modifications centered around a "low-calorie, high-protein" form of the Mediterranean diet, 72 participants saw 9% reductions in body weight, the researchers said.
In addition, their measurements on several key indicators of heart health -- including assessments for arterial stiffness, carotid artery thickening and blood flow -- also improved, data presented Wednesday during the European Congress on Obesity in Maastricht, the Netherlands, showed.
All of the participants had metabolic syndrome -- or at least three of these medical conditions: abdominal obesity, high blood pressure, high blood sugar, high serum "bad" cholesterol and low "good" cholesterol -- at the start of the study, according to the researchers.
This placed them at increased risk for heart disease and other heart-health problems, including heart attack and stroke, the researchers said.
"We found changes in the consumption of specific food components to be linked to better vascular structure and function," co-author Brurya Tal, clinical dietitian at Tel Aviv Sourasky Medical Center in Israel, said in a press release.
Historically, improvements in metabolic and heart health seen after weight loss in people with obesity have been attributed to either the weight loss or the resulting changes in blood sugar and blood pressure levels, Tal and her colleagues said.
However, it is also possible that the make-up of the diet itself, and specific nutrients in that diet, are also involved, the researchers said.
For this study, the Israeli researchers recruited 72 adults with metabolic syndrome and obesity who had an average age of 53 years at the start of the study.
Participants agreed to engage in regular exercise and adhere to a nutrition plan based on the Mediterranean diet, a diet made up largely of foods available in countries that border the Mediterranean Sea, the researchers said.
The Mediterranean diet includes plant-based foods such as fruits, vegetables, whole grains, nuts and legumes as well as "seasonally fresh, locally grown" olive oil and low to moderate amounts of fish and poultry, according to Harvard Medical School.
Previous studies have shown that the Mediterranean diet can reduce the risk for heart disease in those who follow it.
Diet and exercise plans were personalized for each participant and included regular meetings with a physician and dietician, according to the researchers.
Participants were asked to fill in a detailed dietary questionnaire a week before starting their diet and exercise plans and a year later, the researchers said.
Stiffening in the walls of the arteries, which carry blood from the heart, has been linked with an increased risk for heart disease in earlier studies.
So, in this research, the authors used it as a "proxy" for heart health, which they based on the measures pulse wave velocity -- essentially the rate at which blood travels through the circulatory system -- as well as carotid artery intima media thickness and flow mediated dilation, they said.
These latter two measures assess the thickness of the carotid artery, or the main artery from the heart, and the diameter of an artery that causes blood flow to increase, respectively, according to Emory University.
After one year on the diet and exercise plan, participants' body mass index -- a measure of body weight against height -- fell by more than 9%, on average, while average flow mediated dilation improved by 47%, the data showed.
In addition, participants' average pulse wave velocity improved by 13% and carotid artery intima media thickness was enhanced by 1%, the researchers said.
The improvements in pulse wave velocity were associated with reductions in calorie and saturated fat intake as well as increases in zinc intake, as zinc boosts blood vessel health, they said.
The improvements in carotid artery intima media thickness were linked with reductions in calorie and saturated fat intake as well increases in protein, according to the researchers.
Finally, the improvements in flow mediated dilation were attributed to increases in intake of niacin, or vitamin B3, which is known to dilate blood vessels, the researchers said.
"A Mediterranean diet, rich in protein -- lean dairy products, fish, poultry, and eggs -- [and] rich in vegetables, nuts, seeds and with moderate consumption of fruits and grains, can contribute to protecting the cardiovascular system," Tal said.
"The zinc-rich foods in the diet plan were sunflower seeds, pumpkin seeds, nuts and meat, [with] meat and fish provid[ing] niacin," she said.