Perceived and objective diet quality in US adults: a cross-sectional analysis of the National Health and Nutrition Examination Survey (NHANES).

OBJECTIVE: The Dietary Approaches to Stop Hypertension (DASH) dietary pattern has been shown to reduce cardiometabolic risk. Little is understood about the relationship between objective diet quality and perceived diet quality (PDQ), a potential psychosocial barrier to appropriate dietary intake. We compared PDQ and diet quality measured by a nutrient-based DASH index score in the USA. DESIGN: Cross-sectional study. Participants in the 2005-2006 National Health and Nutrition Examination Survey (NHANES) rated diet quality on a 5-point Likert scale and PDQ scores were generated (low, medium, high). A single 24 h dietary recall was used to estimate DASH index scores (range 0-9 points) by assigning 0, 0·5 or 1 point (optimal) for nine target nutrients: total fat, saturated fat, protein, cholesterol, fibre, Ca, Mg, K and Na. SETTING: Nationally representative sample of the US population. SUBJECTS: Adults aged ≥19 years in 2005-2006 NHANES (n 4419). RESULTS: Participants with high PDQ (33 %) had higher DASH index scores (mean 3·0 (sd 0·07)) than those with low PDQ (mean 2·5 (sd 0·06), P < 0·001), but average scores did not align with targets for intermediate or optimal DASH accordance. Adults with high PDQ reported higher total fat, saturated fat and Na intakes compared with optimal DASH nutrient goals. Differences between those with high v. low PDQ were similar for Whites and Blacks, but there was no difference between PDQ groups for Mexican Americans. CONCLUSIONS: Among Whites and Blacks, but not Mexican Americans, high PDQ may be associated with higher diet quality, but not necessarily a diet meeting DASH nutrient goals. This disconnect between PDQ and actual diet quality may serve as a target in obesity prevention.