Study Finds that US Adolescents Have Low Adherence to the Mediterranean Diet

Despite the known health benefits of the Mediterranean diet, a recent study found very low adherence among U.S. adolescents.

The Mediterranean diet is high in fresh vegetables, fruits and whole grains. It also includes oily fish (i.e., salmon, mackerel, anchovies and sardines); nuts (i.e., walnuts, pistachios and almonds); olive oil; legumes; and white milk (for children and adolescents). The Mediterranean diet is low in processed or convenience foods, added sugars, red meat and saturated fats.

“Promoting this diet could have important public health benefits, and may improve the health of children and their families,” says, Roy Kim, MD, MPH, Director of the Center for Pediatric Endocrinology at Cleveland Clinic Children’s and first author of the study.

Assessing the diets of US adolescents

Dr. Kim’s study used data obtained from the National Health and Nutrition Examination Survey (NHANES). The NHANES is an annual survey given to a random sample of U.S. residents; participants are interviewed about their nutritional intake, demographic information, physical activity and health-promoting habits.

“Importantly for our study, the NHANES also measures the participants’ height, weight, waist circumference and blood pressure,” says Roy Kim, MD. “It also collects a fasting blood sample to establish participants’ cholesterol, insulin and blood sugar levels.”

Dr. Kim and his colleagues used these data to determine the level to which U.S. adolescents (N = 4,223) were eating foods from a Mediterranean diet. Essentially, the participants reported what they eat normally, and the diet histories were then scored for adherence to the Mediterranean diet.

Adherence was very low overall, according to the study. The only demographic factors significantly associated with Mediterranean diet adherence were higher income and self-identifying as Mexican-American. Lower adherence was identified in Black adolescents.

No significant association between metabolic syndrome and Mediterranean diet in adolescents

The research team then analyzed the data to elucidate the relationship between adherence to the Mediterranean diet and metabolic syndrome. Metabolic syndrome, a condition identifying patients at high risk for developing type 2 diabetes and cardiovascular disease, is a combination of several factors: a large waist circumference, insulin resistance, high blood pressure, an abnormal cholesterol panel (especially a high triglyceride level).

“At the outset, we hypothesized that following the Mediterranean diet would be linked to lower rates of metabolic syndrome. This hypothesis was not confirmed. Although we found that adherence to the Mediterranean diet was related to lower systolic blood pressure, as well as higher HDL cholesterol, or “good” cholesterol, it was not associated with metabolic syndrome overall,” says Dr. Kim.

This was a surprising result for Dr. Kim, who speculates that perhaps the low overall adherence in the group made it difficult to ascertain a trend. Perhaps, he says, if there were more teens with higher adherence, they might have seen some difference in the rates of metabolic syndrome.

Other diet choices are associated with metabolic syndrome

The analysis found that skipping breakfast and eating pulses (dry beans and peas, chick peas and lentils) were linked to metabolic syndrome. “We expected to find the inverse – that higher levels of pulse consumption would be associated with lower levels of metabolic syndrome. We can’t explain this association with our limited data, though we speculate that preparation may be a factor. If the pulses are prepared with animal fat or salt, that might diminish their health benefits,” Dr. Kim suggests.

Recommendations

“There’s a lot of research that shows the health benefits of the Mediterranean diets, and pediatricians should promote it, especially for patients who have higher weights, insulin resistance or high triglycerides. Just expanding the range of foods that kids eat can help a great deal, especially if limiting food and drink that contain added sugars. I’d say we have the most success cutting sugars from drinks, and from trying to add other foods, like fruits, vegetables, nuts and nut butters as snacks. It’s never too late to start trying new foods and trying to get kids to accept healthier foods,” he says.

In addition to promoting this diet, parents should be counseled to introduce the foods gradually and in ways that children will find palatable, according to Dr. Kim. If the foods aren’t normally consumed by the family, pediatricians may need to recommend recipes. It’s also important to be sensitive about how much the foods cost, as the recommended foods often cost more than other items that generally comprise the diets of U.S. adolescents.