Adherence to the planetary health diet and cognitive decline: findings from the ELSA-Brasil study

The EAT–Lancet Commission proposed a planetary health diet to improve human health within planetary boundaries; however, little is known about the association between adherence to this diet and cognitive decline. We used data from three waves of the Brazilian Longitudinal Study of Adult Health to evaluate the association between the planetary health diet and cognitive decline using linear mixed-effects models. Here we show that in 11,737 participants (mean (s.d.) age 51.6 (9.0) years, 54% women and 53% white), higher adherence to the planetary health diet was associated with slower memory decline (P = 0.046) and that income was a modifier in this association (P < 0.001). Adherence to the planetary health diet was associated with slower decline of memory (P = 0.040) and global cognition (P = 0.009) in high-income participants. No association was found among low-income participants. The results of our study highlight that the promotion of healthy dietary patterns should take into consideration income barriers as well as differences in dietary habits to achieve high adherence. Using longitudinal data from the ELSA-Brasil study, Gonçalves et al. report that income is a barrier to how adherence to the sustainable planetary health diet is linked to slower cognitive decline.