Nutrition knowledge and Mediterranean diet adherence in the southeast United States: Validation of a field-based survey instrument

The Mediterranean diet (MD) can reduce chronic disease risk and is a recommended diet for prevention and management of diabetes. Adherence to the MD in the southeast United States where obesity and diabetes are highly prevalent is unknown. The purpose of the present study was to: 1) construct a survey instrument relevant to the general population integrating both MD related nutrition knowledge and adherence questions from previously validated instruments, and 2) assess MD related nutrition knowledge and adherence in a sample population in the southest United States. Adherance was assessed using the validated short MD Adherence Screener (MEDAS). A MD nutrition knowledge (MDNK) questionnaire was developed from previously validated general nutrition knowledge questionnaires and was validated using 127 university students enrolled in three courses with varying levels of nutrition education. Cronbach's α for internal validity of MDNK was acceptable for a short questionnaire (0.653). Test-retest reliability was established (r = 0.853). Field validation of the three-part survey instrument (MEDAS, MDNK and demographic questions) was subsequently performed in 230 adults shopping at supermarkets and farmers markets in eastern Alabama. Total MDNK and MEDAS scores were significantly higher in students with formal nutrition education and in patrons of farmers markets. Greater MD adherence, assessed by dividing MEDAS scores into thirds, was found with increasing formal nutrition education in university students (p = 0.002) and in farmers market participants (p < 0.001). There was a weak but significant association between MDNK and MEDAS scores within university students and participants in the field. Together, the MDNK-MEDAS survey instrument is an effective tool for assessing baseline knowledge and adherence and can be used to target nutritional interventions to improve MD adherence for prevention and management of diabetes and other chronic disease.