The benefits of iron supplementation following blood donation vary with baseline iron status

Abstract

Whole blood donation rapidly removes approximately 10% of a donor's blood volume and stimulates substantial changes in iron metabolism and erythropoiesis. We sought to identify donors who benefit from iron supplementation, describe the nature of the benefit, and define the time course for recovery from donation. Blood samples were collected over 24 weeks following whole blood donation from 193 participants, with 96 participants randomized to 37.5 mg daily oral iron. Changes in total body, red blood cell (RBC), and storage iron, hepcidin, erythropoietin, and reticulocyte count were modeled using semiparametric curves in a mixed model. and the changes were compared among six groups defined by baseline ferritin (<12; 12‐50; ≥50 ng/mL) and iron supplementation. The effect of oral iron on storage and RBC iron recovery was minimal in donors with baseline ferritin ≥50 ng/mL, but sizeable when ferritin was <50 ng/mL. Iron initially absorbed went to RBC and storage iron pools when ferritin was <12 ng/mL but went mostly to RBCs when ferritin was ≥12 ng/mL. Donors with ferritin ≥12 ng/mL had a “ripple” increase in reticulocytes ~100 days after donation indicating physiological responses occur months following donation. Thus, iron supplements markedly enhance recovery from whole blood donation in donors with ferritin <50 ng/mL. However, full recovery from donation requires over 100 days when taking iron. The findings also highlight the value of the study of blood donors for understanding human hemoglobin and iron metabolism and their usefulness for future studies as additional biomarkers are discovered.

A computational model for prediction of ferritin and haemoglobin levels in blood donors

“…This result echoes findings that a donation interval of 56 days is insufficient time for the donor to replete the iron loss through donation, and that iron deficiency in high-frequency donors is common. [33][34][35][36][37][38] Maintaining a threshold of 15 ng/ml for ferritin levels would imply mean donation frequencies of 1.9 per year for women and 4.1 per year for men. Currently maximum donation frequencies are three and five per year, which implies that such a target would have a substantial impact on donor availability.…”

Donation‐induced iron depletion is significantly associated with low hemoglobin at subsequent donations

“…There is mounting evidence that rates of donor deferral due to low-Hb are considerably less in those taking iron supplements, both at the first donation visit and at subsequent donations. [44][45][46][47][48] Only providing donors with information about their (low) ferritin level does not seem to increase their iron intake. 15 The beneficial effects of iron supplementation may be counteracted by more frequent adverse events in donors who receive iron supplementation, which is likely to limit acceptability and compliance.…”

Demographic, clinical, and biochemical predictors of pica in a large cohort of blood donors

“…We previously found that donors with ferritin <12, 12-50, and >50 ng/ml have distinctly different responses to oral iron supplementation following whole blood donation suggesting that these ferritin strata define different degrees of functional iron deficiency. 24 Therefore, these strata were used to correlate donor iron status with pica behaviors (Table 2). Among those chewing ice, 27% (331 of 1240) had ferritin <12 ng/ml, while 18% (1818 of 10,102) of those not chewing ice had ferritin <12 ng/ml (χ 2 = 56.89, p < .001).…”

“…Similar trends were observed among those eating greater than 8 oz of ice at least once a day (χ 2 = 48.12, p < .001). Non-ice substances chewing that were reported include, but not limited to (may overlap), clay (9), dirt (7), starch (15), raw pastas (73), chalk (8), coal (1), paper (38), or other substances (24). Among those chewing non-ice substances, 30% (38 of 129) had ferritin <12 ng/ml, while 19% (2108 of 11,212) of those not chewing non-ice substances had ferritin <12 ng/ml (χ 2 = 10.69, p = .005).…”

“…, starch(15), raw pastas (73), chalk(8), coal (1), paper (38), or other substances(24). Ten donors reported non-ice substance eating and ice eating (> 8 oz) at least once a day.…”