Fig. 1.

High-iron consumption impaired growth, caused cardiac hypertrophy, and increased mortality, but higher dietary copper prevented these abnormalities. Weanling C57BL/6 mice were fed 1 of 6 diets varying only in iron and copper content for 5 wk ad libitum. Final body weight (A) and growth rates (B) were subsequently determined. Heart weight normalized to body weight (C) was also determined at euthanasia. Data are presented as box plots representing 4 (heart weight) or 7–12 (final body weight and growth rate) mice per group. Data were analyzed by 2-way ANOVA on ranks analysis. Significant iron main effects were noted for final body weights (P < 0.0001), growth rates (P = 0.0019), and heart weights (P = 0.0097). A copper main effect was also noted in regard to heart weights (P = 0.0115). Two-way Fe × Cu interactions were also noted (as indicated in A–C). Since significant 2-way interactions were observed, Tukey’s multiple comparisons post hoc test was utilized to determine differences among individual groups for each parameter; labeled means without a common letter differ (P < 0.05). Mortality (D) was also monitored since some mice died during the 5-wk feeding trial (n = 12 per group). L, low; Ad, adequate; H, high. Note that these same abbreviations are used in all figures.