Adherence To a Mediterranean Diet Lowers Risk of Diabetes

The role of the Mediterranean diet: eating healthy and maintaining a healthy body weight can potentially reduce the risk of developing diabetes for the US population.

A Mediterranean diet is one of the few healthy eating methods associated with a significant health improvement. It is rich in fruits, vegetables, whole grains, fish, legumes, and olive oil and is more common in European countries. It is recommended by the American Heart Association, American Diabetes Association, and Dietary Guidelines for Americans to reduce chronic disease risk. In addition, it is associated with a reduced risk of diabetes in Mediterranean and European countries. However, it is unclear that the Mediterranean diet reduces the risk of developing diabetes in the US population. This research evaluated whether a Mediterranean-style eating pattern is associated with diabetes risk in a large US cohort study of Black and white men and women.

This study was a prospective cohort study that included patients in past research, the Atherosclerosis Risk in Communities (ARIC) study, that investigated the causes of heart diseases in over 400,000 adults in the US. In this study, data were collected for 11,991 participants at their first visit. Participants were excluded if they were Asian or Indian due to small sample size; were Black and from Maryland and Minnesota due to inability to decipher the influence of geographic region versus race; if they had prevalent or history of cardiovascular disease, diabetes, or cancer; or if they derived from food frequency questionnaire (FFQ) responses or had ten or more missing FFQ items.

One of the statistical methods was an FFQ questionnaire to capture each patient’s food consumption at their first and third visit. The data recorded from the survey was used in the Alternate Mediterranean Diet (aMed) scores. The scores ranged from 0 to 9 points, where 1 point was given if the patient self-reported the intake of vegetables, fruit, or legumes and 1 point if they reported red or processed meat consumption. The higher the aMed score, the higher the adherence to a Mediterranean-style diet. They also used the Cox proportional hazards regression models to estimate hazard ratios and confidence intervals for the associations between aMed scores and incident diabetes. Incident diabetes was defined as: if the patient received a physician diagnosis, used diabetes-related medication during the previous two weeks, had a fasting blood glucose of 126 mg/dL or above, or non-fasting blood glucose of 200 mg/dL or above. Also, variables were used in the Cox regression analyses, including energy intake, age, sex, race, education level, smoking status and physical activity, and clinical mediators of diabetes. They were all stratified by race and body mass index (BMI).

During a median follow-up of 22 years, this analysis found 4,024 incident cases of diabetes among the 11,991 participants. In summary, the aMed scores and incident diabetes were higher among Blacks than whites but lowered the risk of diabetes in both races by up to 17%. Also, it was found that the associations between aMed scores and incident diabetes were more influential in patients with a healthy BMI at baseline, which shows that having obesity or overweight outweighs the benefit of a healthy Mediterranean diet, as shown in the ARIC study and other US populations. Therefore, the results of this study indicate that implementing a Mediterranean diet in the absence of weight loss may not reduce diabetes risk in overweight or obese populations. While adherence to a Mediterranean diet could affect lowering the risk of diabetes with those with a healthy BMI, discussion of calorie restriction to achieve and maintain a healthy body weight should remain one of the primary vital roles of diabetes prevention. Overall, eating and adhering to a Mediterranean diet lowers the risk of diabetes in a community-based US population, especially for Black and normal-weight individuals. Future studies should be done to determine if a Mediterranean diet, resulting in clinically meaningful weight loss, can reduce future diabetes risk in individuals with overweight or obesity.

Practice Pearls:

• Having a diet rich in fiber, fruits, vegetables, fish, and olive oil is associated with a lower risk of developing diabetes in the US population.
• There are stronger associations between Mediterranean pattern adherence and incident diabetes for Blacks compared to the white population in the US.

O’Connor, L.E., Hu, E.A., Steffen, L.M. et al. Adherence to a Mediterranean-style eating pattern and risk of diabetes in a US prospective cohort study. Nutr. Diabetes 10, 8, (2020). https://doi.org/10.1038/s41387-020-0113-x

Kenya Henderson, 2021 PharmD. Candidate, Florida Agricultural & Mechanical University, College of Pharmacy and Pharmaceutical Sciences