Dietary share of ultra-processed foods and metabolic syndrome in the US adult population.

ABSTRACT

This study sought to examine the relationship between dietary share of ultra-processed foods and metabolic syndrome among US adults. We studied 6, 385 participants from the cross-sectional National Health and Nutrition Examination Survey 2009-2014, aged 20+ years, with blood tests under fasting conditions and at least one 24-hour dietary recall. Food items were classified according to the extent and purpose of industrial food processing. Ultra-processed foods (UPF) are formulations of many ingredients, mostly of exclusive industrial use, that result from a sequence of industrial processes (hence ultra-processed). Metabolic Syndrome (MetS) was defined according to the 2009 Joint Scientific Statement as meeting three or more of the following criteria (1) elevated waist circumference (2) elevated fasting plasma glucose (3) elevated blood pressure (4) elevated triglycerides (5) reduced high-density lipoprotein (HDL-C). Poisson regression models with robust variance adjusted for age, sex, race/ethnicity, family income, education, physical activity and smoking showed significant linear association between the dietary contribution of UPF and the prevalence of MetS (a 10% increase in contribution was associated with a 4% prevalence increase) (prevalence ratio -PR- = 1.04; 95% CI 1.02, 1.07). A dietary UPF contribution of >71% (5th population quintile) was associated with 28% higher prevalence of MetS compared to a contribution below 40% (1st population quintile) (PR = 1.28; 95% CI 1.09, 1.50). The association was stronger in young adults (PR between upper and lower quintiles = 1.94; 95% CI 1.39, 2.72) and decreased with age. These findings add to the growing evidence that UPF consumption is associated with diet-related non-communicable diseases.