Association of dietary diversity and cognition in preschoolers in rural China

•Dietary diversity is still very low among rural preschoolers in China.•There was a huge difference between children in consumption of most food groups.•Dietary diversity is positively associated with child cognition. We sought to investigate the cognition of preschoolers in rural China and examine the relationship between dietary diversity and cognition. We performed a cross-sectional survey analysis. In 1334 preschoolers ages 3 to 5, from 26 preschools in two nationally designated poverty counties in Hunan Province in China, we calculated the dietary diversity score (DDS) using a 24-h recall method. To measure children's cognitive ability, we assessed the Working Memory Index and Verbal Comprehension Index on the Mandarin-language version of the Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition. Multiple linear regression models were used to estimate the association between DDS and cognitive test scores. A total of 22% of children had a Working Memory Index that was either extremely low or borderline, and 31% of children had a Verbal Comprehension Index that was either extremely low or borderline. The mean (± SD) DDS was 5.65 ± 1.30. Those preschoolers with medium DDS (5 or 6) or high DDS (7 to 9) scored higher on both Working Memory Index—respectively, mean difference (MD), 1.327; 95% confidence interval (CI), 0.246–3.901; and MD, 2.067, 95% CI, 0.261–4.641—and Verbal Comprehension Index—MD, 0.168; 95% CI, 0.072–2.135; and MD, 0.398; 95% CI, 0.032–2.137—than did those with low DDS (0 to 4). Consuming a more diverse diet may contribute to better cognition in preschoolers. Future research is needed to better understand the possible causal effect of dietary diversity on cognitive development.