Association of combined ultra-processed food intake (ultra-processed dietary pattern) with cognitive function impairment: a meta-analysis of prospective cohort studies

Abstract

Background: Previous studies on ultra-processed foods (UPF) and cognitive impairment often isolated UPF from overall dietary patterns, limiting real-world interpretation.

Methods: We systematically searched PubMed, Embase, Web of Science, and Cochrane Library up to April 2026 for prospective cohort studies assessing total UPF intake (defined by NOVA) and risk of cognitive impairment (including cognitive dysfunction, dementia, and Alzheimer's disease). A random-effects model was used to pool adjusted hazard ratios (HRs) comparing highest versus lowest UPF consumption.

Results: Eight cohort studies (total > 250,000 participants) were included. High combined UPF intake was associated with a 14% higher risk of cognitive impairment (pooled HR = 1.14, 95%CI 1.04-1.25, I² = 64.6%). The association was more pronounced in participants aged < 60 years (HR = 1.19, 95%CI 1.06-1.33) but not statistically significant in those > 60 years. Large studies (> 10,000) and longer follow-up (> 15 years) showed stable estimates with lower heterogeneity.

Conclusion: Higher consumption of UPF within a ultra-processed dietary context is positively associated with cognitive impairment risk, particularly among middle-aged adults. These findings support dietary guidelines that recommend limiting UPF intake.

Keywords: Alzheimer’s disease; Cognitive function impairment; Dementia; NOVA; Ultra-processed dietary pattern; Ultra-processed food.