Higher dietary phytochemical index is associated with anthropometric indices in children and adolescents: The weight disorders survey of the CASPIAN-IV study

Objectives: The present study aimed to determine the association of total dietary phytochemical intake with generalized and abdominal obesity in children and adolescents. Material and methods: This nationwide cross-sectional study was conducted in 4296 students aged 6-18 years. Dietary phytochemical index (DPI) was calculated as a percentage of daily energy derived from phytochemical-rich foods divided by total daily energy intake. Results: The mean +/- standard error of DPIs in the first, second, third and fourth quartiles were 12.70 +/- 3.28, 20.36 +/- 1.84, 27.52 +/- 0.08 and 41.10 +/- 0.26, respectively. Anthropometric measures including weight Z-score (-0.04 vs. 0.05, P = 0.023), body mass index (BMI) Z-score (-0.05 vs. 0.06, P = 0.013), waist circumference (WC) (65.80 cm vs. 66.95 cm P = 0.022), hip circumference (HC) (80.20 cm vs. 81.37 cm, P = 0.046), and neck circumference (NC) (30.06 cm vs. 30.45 cm, P = 0.031) were significantly lower among participants in the upper DPI quartile compared to those in the lower quartiles. In overweight and obese children, higher adjusted DPI scores had inverse correlation with BMI, WC, HC, wrist circumference, and NC (beta s = -0.077, -0.10, -0.119, -0.01, and -0.032, respectively; P < 0.05). Comparison of the fourth quartile with the first quartile of DPI revealed beneficial effects of higher phytochemical intake on reducing the risk of obesity/overweight and abdominal obesity. However, these results were not statistically significant (P = 0.073). Conclusion: Higher DPI score was associated with lower risk of generalized and abdominal obesity in children and adolescents. However, the results were not statistically significant. Consuming phytochemical-rich foods can be encouraged to prevent childhood obesity.