Italian and Greek researchers conducting a meta-analysis* of the diets of more than 500,000 people have concluded that the Mediterranean diet reduces the risk of metabolic syndrome, a cluster of risk factors that are common precursors to type 2 diabetes. Those factors include overweight or obesity, a sedentary lifestyle, high blood sugar, high triglyceride levels, high blood pressure, and high “bad” cholesterol.
The Mediterranean diet is high in fruit, vegetables, whole grain foods, and low-fat dairy products. Proteins include fish, legumes, poultry, tree nuts, and mono-unsaturated fatty acids from olive oil. Alcohol intake is moderate and almost always in conjunction with meals. Red meat is only an occasional menu item.
The scientists looked at 50 studies that involved more than 500,000 people, then extrapolated the effects of a Mediterranean diet from them. Although the meta-analysis pointed to the usefulness of the Mediterranean diet in fending off metabolic syndrome, its authors said that their conclusion is tentative, given the need for more research on the topic.
The study was published in the March 15 issue of the Journal of the American College of Cardiology.
* A meta-analysis looks at a number of similar studies and tries to derive new and useful results from them by detecting common patterns among them.
TUESDAY, March 8 — The Mediterranean diet, long known to be heart-healthy, also reduces the risk of metabolic syndrome, a cluster of risk factors that boost the risk of heart disease, stroke and diabetes, according to a new review.
Researchers from Greece and Italy reviewed the results of 50 published studies with a total of more than 500,000 participants as part of a meta-analysis — a statistical analysis of the findings of similar studies — on the Mediterranean diet.
Among their findings: the natural foods-based diet is associated with a lower risk of hikes in blood pressure, blood sugar and triglycerides, as well as a reduced risk of a drop in good cholesterol — all of which are risk factors in metabolic syndrome.
“It is one of the first times in the literature, maybe the first, that someone looks through a meta-analysis at the cardiovascular disease risk factors and not only the hard outcome” of heart disease and other conditions, said Dr. Demosthenes Panagiotakos, an associate professor at Harokopio University of Athens in Greece.
The study is published in the March 15 issue of the Journal of the American College of Cardiology.
The Mediterranean diet is a pattern marked by daily consumption of fruits, vegetables, whole grain cereals, and low-fat dairy products; weekly consumption of fish, poultry, tree nuts, and legumes; high consumption of monounsaturated fatty acids, primarily from olives and olive oils; and a moderate daily consumption of wine or other alcoholic beverages, normally with meals. Red meat intake and processed foods are kept to a minimum.
Metabolic syndrome — increasingly common in the United States — occurs if someone has three or more of the following five conditions: blood pressure equal to or higher than 130/85, fasting blood glucose equal to or higher than 100 mg/dL, a waist measuring 35 inches or more in women and 40 inches or more in men, a HDL (“good”) cholesterol under 40 in men and under 50 in women, triglycerides equal to or higher than 150 mg/dL.
In the review, Panagiotakos and his team found the Mediterranean diet “is strongly associated with decreased metabolic syndrome risk,” declining to pinpoint an exact percentage because the data would not fully support it.
The research team also noted that further study was needed, as a few of the studies reviewed also included interventions such as physical activity and smoking cessation.
The findings come as no surprise, said Dr. Ronald Goldberg, professor of medicine at the Diabetes Research Institute, University of Miami Miller School of Medicine, who reviewed the findings. Since many studies have confirmed the role of the Mediterranean diet on reducing heart disease, he noted, it makes sense that the diet would also reduce the risks that lead up to heart disease.
But since Americans are fond of processed and fast foods, how willing would they be to adopt the diet? “Not particularly,” Goldberg acknowledged. But, he added, nutrition experts, recognizing that reluctance, have recently begun efforts to adapt the diet to different cultures — for example, including many traditional Hispanic foods into a Mediterranean diet adapted for those of Hispanic descent.
By doing so, the diet not only provides the same nutrients as the Mediterranean diet, but the familiar food of one’s ethnicity, Goldberg said.
Panagiotakos says even U.S. fast-food-lovers can eat more like Mediterranean’s. “Even in fast-food, we can introduce healthy eating, like salads, fruits and vegetables, cereals and legumes, and use good sources of fat. We can replace burgers with all these products — it is a matter of nutrition education.”
(Reuters Health) – Eating a Mediterranean diet may prevent or even reverse metabolic syndrome, a cluster of risk factors for heart disease and diabetes, according to a new study.
The Mediterranean diet includes an abundance of fruits, vegetables, beans, nuts, olive oil, poultry and fish, with very little red meat. Scientists believe that eating this way has antioxidant and anti-inflammatory effects on the body.
“This study reinforces guidelines over the past 10 years, stressing the need to reduce consumption of refined carbohydrates and saturated fats” from meat and dairy products, Dr. Robert S. Rosenson of the Mount Sinai School of Medicine in New York told Reuters Health. He was not involved in the work.
Metabolic syndrome is a recent catchall for unhealthy traits that spell bad news for the heart, such as belly fat, high blood pressure, low levels of “good” HDL cholesterol, elevated fat levels in the blood (triglycerides), and high blood sugar. The condition is diagnosed when a person has at least three of those risk factors.
Reviewing 35 clinical trials, Dr. Demosthenes B. Panagiotakos at Harokopia University in Athens, Greece, and his team found that faithfully eating a Mediterranean diet can improve each of those traits.
For instance, those who stuck with the Mediterranean diet as compared to eating their regular foods or a low-fat diet trimmed their waistlines by about 0.43 cm (0.16 inches) on average.
They also showed slashed their blood pressure by 2.35 points on the top reading, and their fasting blood sugar by 3.89 milligrams per deciliter.
While these benefits may seem small, Dr. Elizabeth Mayer-Davis, who was not involved in the research, said they show a Mediterranean diet might be beneficial.
“So it’s reasonable to recommend the Mediterranean diet to patients,” she said. But she added that “we can’t say that this diet reduces the risk of diabetes.”
Nor does the study, published in Journal of the American College of Cardiology, show that the diet cuts the risk of death from heart disease, which has been linked to metabolic syndrome.
Mayer-Davis, professor of nutrition at the University of North Carolina at Chapel Hill, also said she was concerned that cost could be a barrier to adopting a diet that emphasizes fresh foods, olive oil and fish.
“This speaks to the need to improve availability of these kinds of foods to people who don’t have a lot of extra money to spend,” she told Reuters Health.
Olive oil is an important part of the Mediterranean diet because it is a so-called monounsaturated fat, which “protects” levels of HDL cholesterol.
However, it can cost a lot more than other cooking oils on supermarket shelves. Rosenson said that when he suggests this diet to his patients, he makes the point that the much cheaper canola oil is also high in monounsaturated fats.
Dr. Robert Eckel, a former president of the American Heart Association who reviewed the study for Reuters Health, noted that the Mediterranean diet “is part of a dietary pattern consistent with guidelines from the AHA, the USDA, and other bodies, that overall is consistent with reduced risk for cardiovascular disease, stroke and diabetes.”
In other words, he added, “there’s nothing really new here.”
He noted that people often misconstrue the concept of a Mediterranean diet as simply adding olive oil. “If they continue eating a lot of saturated fat and refined carbohydrates, they’re mistaken in what the dietary pattern is all about,” he said.
Eckel, of the University of Colorado Denver School of Medicine, also had several criticisms of the new review. For instance, he pointed out that the comparison diets and other lifestyle modifications varied broadly, and some studies were very short.
“Follow-up in the clinical trials varied from 1 month to 5 years – it’s hard to make conclusions after 1 month!”
SOURCE: bit.ly/hNLotz Journal of the American College of Cardiology, online March 7, 2011.