Whether substituting high-fat dairy with low-fat dairy changes the risk of attention-deficit hyperactivity disorder: A case–control study

Background Attention-deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder in children, with potential influences from modifiable dietary factors. Evidence on the differential effects of low-fat and high-fat dairy on ADHD risk is limited. Aim To examine associations between total, low-fat, and high-fat dairy intake and ADHD risk, and to assess the impact of substituting high-fat dairy with low-fat dairy in children. Methods A case–control study was conducted on 150 Iranian children aged 4–12 years, including 62 with ADHD and 88 controls. Dietary intake was assessed using a validated semi-quantitative food frequency questionnaire. Logistic regression was used to examine the association between dairy intake and ADHD risk, adjusting for energy intake, body mass index, age, sex, and socioeconomic status. Substitution analysis evaluated the effect of replacing 1 g/day of high-fat dairy with low-fat dairy. Summary Children with ADHD consumed significantly less total and low-fat dairy than controls, whereas high-fat dairy intake did not differ significantly between groups. Higher total and low-fat dairy intakes were inversely associated with ADHD risk (odds ratio (OR) = 0.974 and 0.970, respectively; both P < 0.001). High-fat dairy intake was not significantly associated with ADHD risk after full adjustment. Substituting 1 g/day of high-fat dairy with low-fat dairy was associated with lower odds of ADHD (OR = 0.981; P = 0.029). These findings suggest that greater consumption of total and low-fat dairy, as well as replacing high-fat with low-fat dairy, may be associated with lower ADHD risk in children.