Association between nutrient intake and anemia in Brazilian adolescents.

Aims: The association between the intake of iron, vitamins A and C and calcium and the prevalence of anemia and hemoglobin (Hb) levels was investigated in adolescents.

Methods: A cross-sectional study was developed with 529 Brazilian students. Anemia was defined in terms of Hb concentration. Nutrient intake was assessed by a 3-day food record. The association between the prevalence of inadequate nutrient intake and anemia was estimated by the χ(2) test, and that between nutrient intake and Hb by linear regression.

Results: The prevalence of inadequate nutrient intake did not differ between nonanemic and anemic subjects. Anemic adolescents had a lower mean intake of iron than nonanemic adolescents. Among boys aged 11-13 years, the anemic subjects had lower vitamin C intake than those who were nonanemic (41.1 vs. 62.6 mg, p < 0.01), and among those aged 14-19 years, there was a tendency for a positive association between Hb and heme iron intake (β = 0.64, p = 0.06) and a negative association with calcium intake (β = -0.003, p = 0.02). In females, daily nutrient intake did not differ between anemic and nonanemic individuals.

Conclusions: Heme iron and vitamin C are possible protective factors against anemia in boys. However, the lack of association between inadequate iron intake and anemia, especially in girls, suggests that other factors beyond diet could explain anemia in this age range.