Plasma Aldosterone Concentration Depressed by Iron Deficiency

To investigate effects of iron (Fe) and zinc (Zn) deficiency on blood pressure and plasma aldosterone concentration, forty 4-week-old male Sprague-Dawley rats were assigned into 4 dietary treatment groups of 10 for the 4-week study: Fe-deficient group (30 mg Zn/kg, no supplemental Fe; FD), Zn-deficient group (4.5 mg Zn and 35 mg Fe/kg; ZD), Fe/Zn-deficient group (no supplemental Fe, 4.5 mg Zn/kg; FZD), and control group (AIN-93G; Cont). At day 26–27, blood pressure was measured by tail cuff method. Plasma aldosterone concentration was determined by ELISA. Statistical analysis was performed by two-way ANOVA. Heart weight per body weight was increased by Fe deficiency (P<0.001) and was decreased by Zn deficiency (P<0.05). Compared to Cont, hematocrit was significantly decreased in both FD and FZD, and was significantly increased in ZD (P<0.01). Systolic, diastolic and mean blood pressures were decreased by Fe deficiency (P<0.001). Plasma aldosterone concentration was significantly decreased by Fe deficiency (P<0.001). These results suggest that Fe deficiency decreases blood pressure. Hypotension in Fe deficiency may be caused by decreased plasma aldosterone concentration in addition to the decreased blood viscosity due to the low hematocrit.