A healthy quality Mediterranean diet partially alters the relationship between obesity and cardiovascular mortality. That's according to a new study published this week in PLOS Medicine by Karl Michaëlsson of Uppsala University, Sweden and colleagues.
Higher body mass (BMI) caused 4.0 million deaths worldwide in 2015, and more than two-thirds of those deaths were due to cardiovascular disease (CVD). Studies have shown that other factors, including healthy eating habits, could alter the higher risk of CVD associated with a higher BMI. In the new study, the researchers looked at the BMI, diet and mortality of 79,003 Swedish adults who were included in the Swedish mammography cohort and the cohort of Swedish men. Adherence to a Mediterranean Diet (mMED) was rated on a scale from 0 to 8, taking into account information about intake of fruits and vegetables, legumes, nuts, unrefined or high fiber grains, fish, red and processed meat, and olive oil. Information was also available on the age, physical activity, smoking, and socio-economics of the cohort participants.
Over 21 years of follow-up, 30,389 (38% of participants) died. Among overweight subjects, those with high mMED (HR 0.94; 95% CI 0.90-0.98 compared to subjects of normal weight and high mMED) were the group with the lowest hazard ratio (HR) for all-cause mortality. Overweight subjects with high mMED did not have a significantly higher mortality than subjects with normal weight and high mMED (HR 1.03; 95% CI 0.96-1.11). Conversely, people with a normal BMI but low mMED had a higher mortality (HR 1.60; 95% CI 1.48-1.74) than people with a normal weight and high mMED. For CVD mortality, which accounted for 12,064 deaths, the results were broadly similar. Although the CVD morale associated with high BMI was lowered by following a Mediterranean diet, it was not completely counteracted. In addition, a lower BMI did not counteract the increased CVD mortality associated with a low mMED.
"These results suggest that following healthy diets such as a Mediterranean diet may be a more appropriate focus than avoiding obesity to prevent all-cause mortality," say the authors. "Even so, a healthy diet cannot fully counteract the higher CVD mortality associated with obesity."