NEW YORK – A traditional Mediterranean-style diet does not appear to be better at controlling glycemia, but its other healthy effects make it a worthwhile alternative to other diet plans for people with diabetes, according to nutritionist Jackie L. Boucher.
Definitions vary somewhat, but the Mediterranean dietary pattern – fruits and vegetables, whole grains, fish, olive oil, nuts and legumes, and red wine – is consistent with other nutritional plans for patients with diabetes, including Dietary Approaches to Stop Hypertension (DASH) and the American Diabetes Association (ADA) diet, she said at the annual advanced postgraduate course held by the American Diabetes Association.
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Mediterranean dietary patterns may help mitigate risk factors associated with diabetes.
"I think the Mediterranean-style diet can fit with recommendations for the prevention and treatment of diabetes," said Ms. Boucher, vice president for education and director of the Heart of New Ulm Project for the Minneapolis Heart Institute Foundation.
Both the ADA and Mediterranean eating plans encourage patients to be active and eat foods lower in saturated and trans fats, and combined with the dietary guidance provided by diabetes educators and nutritionists, can help to prevent some of the more dire complications associated with diabetes, she said.
Her presentation coincided with the online publication in the New England Journal of Medicine of a randomized clinical trial from Spain, showing that among persons at high risk for cardiovascular disease, including many with type 2 diabetes, a Mediterranean diet supplemented with extravirgin olive oil or nuts significantly reduced the incidence of major cardiovascular events. The study did not look at the effect of diet on glycemia, however.
Call it an ‘eating pattern’
A Mediterranean diet, as defined in 1993 in a European consensus conference, is rich in plant-based foods (vegetables, fruits, grains, nuts, and seeds); uses minimally processed and seasonal locally grown foods; and includes fruit as the typical daily dessert, supplemented with sweets based on nuts, olive oil, and honey or concentrated sugars on special occasions. Dairy products are eaten in low to moderate quantities, red meat is consumed infrequently, and meals are usually accompanied by wine in low to moderate amounts.
There are different regional flavors of the diet, with Greeks getting about 40% of total energy from fat, compared with about 30% from fat for Italians. Italians eat more pasta than the Greeks or Spaniards, and Spaniards typically eat more fish. Therefore, it makes sense to think of it more as an eating pattern than as a diet, Ms. Boucher said.
Evidence-based studies have hinted that such dietary patterns may protect against coronary heart disease, type 2 diabetes, hypertension, thromboembolic events, osteoporosis, and cancers of the breast, stomach, colorectal tract, and prostate, she said.
However, different study methodologies and definitions of a Mediterranean-style eating pattern have made it hard to tease out specific effects of following such a pattern. Additionally, some studies do not control for physical activity or for social engagement during meals, while others may exclude wine, which has been shown to offset lipid peroxidation from red meat consumption when the wine is taken with the meal.
Mixed results
A recently published systematic review of studies of macronutrients, food groups, and eating patterns in the management of diabetes noted that most studies leave out energy balance and healthy eating patterns, which are considered to be essential components of medical nutrition therapy.
Regarding the question of an optimal macronutrient ration for glycemic management and cardiovascular risk reduction in people with diabetes, the authors found that although "in many instances there were not statistically significant differences between dietary approaches, improvements were often seen from baseline to follow-up in both intervention groups, supporting the idea that several different macronutrient distributions may lead to improvements in glycemic and/or [cardiovascular disease] risk factors."
Although the Mediterranean diet pattern does not appear to have specific benefits on glycemic control when compared with other diet plans or healthy eating patterns, the general principles of eating whole foods, eating in moderation, and eating a variety of plant-based foods can be safely recommended to patients with diabetes, Ms. Boucher said.
She reported having no relevant financial disclosures.