Healthy diet scores and ultra-processed foods with incident coronary heart disease: a prospective study

The extent to which adherence to healthy dietary patterns impacts the association between ultra-processed food (UPF) intake and coronary heart disease (CHD) remains uncertain, particularly in Middle Eastern populations undergoing rapid nutritional transitions. We examined the independent and joint associations of several healthy diet scores and UPF consumption with incident CHD in Iranian adults.

We analyzed 2,921 men and women from the Tehran Lipid and Glucose Study who were free of cardiovascular disease at baseline. Diet was assessed using a food-frequency questionnaire, and the Mediterranean diet (MeDi), Dietary Approaches to Stop Hypertension (DASH), the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND), and the healthful Plant-based Diet Index (hPDI) scores were calculated. UPF intake was also calculated. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

Over a median follow-up of 10.6 years, higher UPF intake was associated with increased CHD risk (HR: 1.57; 95% CI: 1.02-2.43); in contrast, higher MeDi, DASH, and MIND scores were inversely associated with CHD. The associations for the hPDI were weaker. Joint analyses revealed that participants with low UPF consumption in combination with healthy diet scores had a significantly reduced risk of CHD. The hazard ratios were 0.47 (95% CI: 0.29-0.75) for the MeDi, 0.56 (95% CI: 0.37-0.85) for the DASH, 0.59 (95% CI: 0.38-0.90) for the MIND, and 0.59 (95% CI: 0.38-0.93) for the hPDI scores. Furthermore, high MeDi (HR: 0.50; 95% CI: 0.31-0.83) and high DASH (HR: 0.58; 95% CI: 0.36-0.92) scores were associated with a lower CHD risk even among participants with high UPF intake.

In this Iranian cohort, MeDi, DASH, and MIND were more informative than hPDI for CHD risk. The favorable CHD risk profile was shown in participants with high adherence to the MeDi and DASH scores combined with either low or high UPF intake. Adherence to the MIND and hPDI scores is effective only in those with low UPF consumption.