The traditional Mediterranean diet provides substantial protection against type 2 diabetes, according to a study published on bmj.com.

The Mediterranean diet is rich in olive oil, grains, fruits, nuts, vegetables, fiber   and fish, but low in meat, dairy products and alcohol. Current evidence suggests that such a diet has a protective role in cardiovascular disease, but little is known about its role on the risk of developing diabetes in healthy populations.

The Sun Prospective Cohort Study 

The SUN prospective cohort study involved over 13 000 graduates from the University of Navarra in Spain with no history of diabetes, who were recruited between December 1999 and November 2007, and whose dietary habits and health were subsequently tracked.

Participants initially completed a 136 item food frequency questionnaire designed to measure the entire diet. The questionnaire also included questions on the use of fats and oils, cooking methods and dietary supplements.

Every two years participants were sent follow-up questionnaires on diet, lifestyle, risk factors, and medical conditions. New cases of diabetes were confirmed through medical reports.

During the follow-up period (median 4.4 years) the researchers from the University of Navarra found that participants who stuck closely to the Mediterranean diet had a lower risk of diabetes.  A high adherence to the Mediterranean diet was associated with an 83% relative reduction in the risk of developing diabetes.

Interestingly, those participants who stuck strictly to the Mediterranean diet also had the highest prevalence of risk factors for diabetes such as older age, a family history of diabetes, and a higher proportion of ex-smokers. This group of participants was therefore expected to have a higher incidence of diabetes, but this was not the case.  If fact, say the authors, they had a lower risk of diabetes, suggesting that the Mediterranean diet might provide substantial protection.

The major protective characteristics of the Mediterranean diet include a high intake of fiber and vegetable fat, a low intake of trans fatty acids, and a moderate intake of alcohol. In addition, a key element of the diet is the abundant use of virgin oil for cooking, frying, spreading on bread, and dressing salads.

The authors conclude by calling for larger cohorts and trials to confirm their findings.

About Type 2 Diabetes

Type 2 diabetes is also referred to as non-insulin dependent diabetes mellitus (NIDDM), or adult onset diabetes mellitus (AODM).

Type 2 diabetes is characterized by high levels of blood sugar, caused by the body's inability to utilize insulin to move blood sugar into the cells for energy. In type 2 diabetes, patients can still produce insulin, but do so relatively inadequately for their body's needs, particularly in the face of insulin resistance as discussed above. In many cases this actually means the pancreas produces larger than normal quantities of insulin.

A major feature of type 2 diabetes is a lack of sensitivity to insulin by the cells of the body (particularly fat and muscle cells). In addition to the problems with an increase in insulin resistance, the release of insulin by the pancreas may also be defective and suboptimal. High plasma levels of insulin and glucose due to insulin resistance often lead to metabolic syndrome and type 2 diabetes, including its complications.