Effects of coffee consumption on iron, zinc and copper status in nonpregnant and pregnant Sprague-Dawley rats

To investigate the influence of coffee consumption on iron, zinc and copper status, 64 Sprague-Dawley female rats were assigned to four treatment groups: nonpregnant-given coffee, nonpregnant-given water, pregnant-given coffee and pregnant-given water. The coffee groups received a freeze-dried coffee solution (1.1% w/v) as the sole source of liquids during the 18-day study period; all groups were provided a purified diet marginal in iron ad libitum. On day 18 (of gestation in the pregnant rats), rats were intubated with 0.033 MBq ⁵⁹Fe after an 8 h fast and killed 4, 8, 12 or 24 h post-gavage. Fluid intake was significantly lower in the coffee groups. Coffee did not affect food consumption, weight gain, hemoglobin or hematocrit in either pregnant or nonpregnant rats. In nonpregnant rats, the percentage of ⁵⁹Fe was lower in plasma and higher in the spleen and erythrocytes in the coffee group than in controls; in pregnant rats the coffee group had a higher percentage of ⁵⁹Fe in the stomach (at 4 h only), blood, spleen and bone than controls. There were no significant effects of coffee on tissue concentrations of Fe, Zn or Cu in the nonpregnant group, but pregnant rats given coffee had high concentrations of Fe in the liver, bone and placenta, and low placenta Zn concentrations compared to controls. In fetuses, there were trends towards lower weight, length, and percentage ⁵⁹Fe, but higher liver Fe, in the coffee group than in the controls. The results suggest that coffee intake leads to (a) increased attempts at erythropoeisis, an indication of iron deficiency, in both nonpregnant and pregnant rats, and (b) impaired placental Fe transport.