Diet is a contributing factor to CVD risk, but how diet quality changes over the long term and contributes to CVD risk is less well studied. Diet data were analysed from parents and offspring from the Princeton Lipid Research Study (24-h recall in the 1970s; Block FFQ in 1998). Diet quality was assessed using an 8-point Dietary Approaches to Stop Hypertension nutrient-based scoring index, including a new method for scoring in children, as well as examining twelve key macro/micronutrients. Outcomes included blood glucose, blood pressure, serum lipids and BMI. The analysis included 221 parents (39 % male, mean age 38·9 ± 6·5 at baseline and 66·6 ± 6·6 at follow-up) and 606 offspring (45 % male, 11·9 ± 3·2 at baseline and 38·5 ± 3·6 at follow-up). Parents’ Dietary Approaches to Stop Hypertension score increased slightly from baseline to follow-up (1·4 ± 1·0 and 2·1 ± 1·3, respectively, P < 0·001), while offspring remained consistent (1·6 ± 0·9 and 1·6 ± 1·1, respectively, P = 0·58). Overall, the Dietary Approaches to Stop Hypertension score, adjusted for age, race, sex and BMI, was not significantly associated with any examined outcomes. Of the macro/micronutrients at follow-up, saturated and total fat were associated with increased diabetes and dyslipidaemia in parents, while the inverse was seen with niacin. Among offspring, niacin was associated with lower rates of hypertension and dyslipidaemia. In conclusion, no relationship was detected between Dietary Approaches to Stop Hypertension adherence and disease outcomes. However, both saturated fat and niacin were associated with components of CVD risk, highlighting the need for improved diet quality overall.