Association between ultra-processed food intake and biological ageing in US adults: findings from National Health and Nutrition Examination Survey (NHANES) 2003–2010

BACKGROUND: The association between ultra-processed food (UPF) intake and markers of biological ageing has been scarcely investigated, despite the evident adverse health effects associated with UPF. This study aimed to test the association between UPF intake and biological ageing, and evaluate how much of this association is accounted for by overall diet quality. METHODS: This cross-sectional study assessed 16 055 participants aged 20-79 years (51% women, 46 ± 0.3 years) from the National Health and Nutrition Examination Survey (NHANES) 2003-2010. Dietary UPF intake was assessed using the Nova system. Values were expressed as % of total energy intake and were denominated as a continuous variable and in quintiles. Diet quality was assessed with the American Heart Association 2020 and the Healthy Eating Index 2015. Biological ageing was assessed using the PhenoAge algorithm. RESULTS: For each 10% of energy intake accounted for by UPF, participants were 0.21 (95%CI 0.16-0.26) years biologically older in terms of PhenoAge. As compared to participants in the lowest UPF quintile (≤39%), those in the highest UPF quintile (68-100%) were 0.86 (95% CI 0.55, 1.16) years older (P-for-trend across quintiles ≤0.001). Adherence to a healthy diet moderately attenuated the relationship between UPF and PhenoAge (adjusted β = 0.14 per 10% increment of UPF). CONCLUSIONS: Adults with higher UPF tended to be biologically older. This association is partly independent of diet quality, suggesting that food processing may contribute to biological ageing acceleration. Our findings point to a compelling reason to target UPF consumption to promote healthier ageing.