Diet quality, nutrient adequacy, and symptom associations in ADHD: A case-control study of Australian adolescents

Nutrition may influence attention-deficit/hyperactivity disorder (ADHD) symptom severity however evidence is limited. This study examined adherence to a healthy dietary pattern, nutrient intakes, and associations with symptoms and cognitive performance in Australian adolescents with ADHD. This case-control study included 39 adolescents (18 ADHD; 21 healthy controls) aged 13-18 years. Groups were compared on dietary variables including Mediterranean diet (MedDiet) adherence (KIDMED) and energy-adjusted nutrient intakes, and on nutrient adequacy against nutrient reference values (NRVs). Associations between dietary variables and self-reported ADHD symptoms (Adult ADHD Self-Report Scale) and cognitive performance (Test of Variables of Attention) were examined. Combined (ADHD-C) and inattentive (ADHD-I) subtypes were also analysed. Dietary variables and nutritional adequacy did not significantly differ between groups, however sweets consumption was greater in ADHD ( p = .002). Group x age interactions were observed for KIDMED ( p = .022, η 2 p = .15), magnesium ( p = .011, η 2 p = .20), and iron ( p = .010, η 2 p = .20), and a group x gender interaction for beta-carotene ( p = .032, η 2 p = .14). The strongest correlations involved KIDMED, vitamin B12, and omega-6:omega-3 with cognitive outcomes (positive), and KIDMED with symptoms (negative). Among subtypes, ADHD-C met more NRVs than ADHD-I (69.2% vs. 38.5%, p = .014). Although few dietary differences were observed between ADHD and controls, symptom and cognitive performance associations highlight the clinical relevance of dietary factors. Larger studies are needed to further examine nutrition in ADHD, particularly the potential moderating effects of age, gender, and subtype. • ADHD and controls displayed similar suboptimal nutrient adequacy and Mediterranean diet adherence. • No overall nutrient intake differences between ADHD and controls. • Several nutrient intakes showed age or gender interactions with group. • Mediterranean diet adherence linked to lower ADHD symptoms. • Mediterranean diet adherence, vitamin B12, and omega-6:omega-3 ratio linked to better cognitive performance