Dietary phytochemical intake and asthma in children: a case-control study.

Pediatric asthma is a chronic inflammatory disease marked by bronchial hyperresponsiveness and airflow obstruction. Diet may be associated with asthma risk and severity through anti-inflammatory and antioxidant effects. This research evaluated the connection between the Dietary Phytochemical Index (DPI), which measures the percentage of daily calories from foods high in phytochemicals, and asthma-related outcomes in pediatric populations. In this case-control study with cross-sectional analyses within the asthma group, 300 children aged 5-12 years (150 asthma cases, 150 matched controls) were evaluated. Dietary intake was measured via a validated food frequency questionnaire. DPI was calculated and categorized into tertiles. Clinical outcomes included the Pediatric Asthma Severity Score (PASS), Childhood Asthma Control Test (C-ACT), and Pediatric Asthma Quality of Life Questionnaire (PAQLQ). Serum C-reactive protein (CRP) was measured as an inflammation marker. Children in the highest DPI tertile had lower CRP levels (1.99 vs. 4.02 mg/L), higher PAQLQ scores (4.33 vs. 3.89), lower PASS scores (6.35 vs. 11.14), and higher C-ACT scores (21.45 vs. 13.91; all p < 0.001) than those in the lowest tertile. Higher DPI was associated with lower inflammation (CRP: β = -0.026), higher quality of life (PAQLQ: β = 0.058), lower asthma severity (PASS: β = -0.148), and higher asthma control (C-ACT: β = 0.364; all p < 0.001). The highest DPI tertile was associated with lower odds of asthma (OR = 0.06; 95% CI: 0.03-0.13; p < 0.001) (fully adjusted for age, sex, BMI, physical activity, energy intake, fiber, and vitamin D). Each one-unit DPI increase was associated with 11% lower odds of asthma (OR = 0.89; 95% CI: 0.86-0.91; p < 0.001), with CRP as the primary inflammation marker assessed.

conclusionGreater intake of phytochemical-rich foods is associated with lower odds of asthma, lower inflammation, and better clinical outcomes in children. WHAT IS KNOWN: • Dietary patterns rich in anti-inflammatory foods may benefit children with asthma. • Phytochemicals have antioxidant and immune-modulating effects relevant to asthma. WHAT IS NEW: • Higher Dietary Phytochemical Index was associated with substantially lower odds of pediatric asthma. • Higher DPI was also associated with lower asthma severity, better asthma control, and lower CRP. • This is the first study to apply DPI to a pediatric asthma population.