TY - JOUR
T1 - Single versus split dose of iron optimizes hemoglobin mass gains at 2106 m altitude
AU - Hall, Rebecca
AU - Peeling, Peter
AU - Nemeth, Elizabeta
AU - Bergland, Dan
AU - Mccluskey, Walter T.P.
AU - Stellingwerff, Trent
PY - 2019/4/1
Y1 - 2019/4/1
N2 - Purpose: To determine if a single versus a split equivalent daily dose of elemental iron was superior for hemoglobin mass (Hbmass) gains at altitude while minimizing gastrointestinal (GI) discomfort. Methods: Twenty-four elite runners attended a 3.1 ± 0.3 wk training camp (Flagstaff, AZ; 2106 m). A two-group design, randomized and stratified to baseline Hbmass, sex, and ferritin (>30 μ·L -1 ), was implemented daily as: 1) single dose of 1 × 200 mg (pm only, SINGLE) versus 2) split dose of 2 × 100 mg (am and pm; SPLIT) elemental iron (ferrous fumarate). The Hbmass and venipuncture assessments were completed upon arrival and departure (±2 d) from camp for ferritin, hepcidin, and erythroferrone (ERFE) concentrations. Validated food frequency, GI distress, menstrual blood loss (MBL) and training questionnaires were implemented throughout. Univariate analysis was used to compare Hbmass, with baseline ferritin, dietary iron intake, MBL, and training volume used as covariates. Results: Both conditions increased Hbmass from baseline (P < 0.05), with SINGLE (867.3 ± 47.9 g) significantly higher than SPLIT (828.9 ± 48.9 g) (P = 0.048). The GI scores were worse in SINGLE for weeks 1 and 2 combined (SINGLE, 18.0 ± 6.7 points; SPLIT, 11.3 ± 6.9 points; P = 0.025); however, GI scores improved by week 3, resulting in no between-group differences (P = 0.335). Hepcidin significantly decreased over time (P = 0.043) in SINGLE, with a nonsignificant decrease evident in SPLIT (22%). ERFE significantly decreased in both groups (28.5%; P < 0.05). No between-group differences existed for ERFE, hepcidin, food frequency, MBL, or daily training outcomes (P > 0.05). Conclusions: A single nightly 200-mg dose of elemental iron was superior to a split dose for optimizing Hbmass changes at altitude in runners over an approximately 3-wk training camp.
AB - Purpose: To determine if a single versus a split equivalent daily dose of elemental iron was superior for hemoglobin mass (Hbmass) gains at altitude while minimizing gastrointestinal (GI) discomfort. Methods: Twenty-four elite runners attended a 3.1 ± 0.3 wk training camp (Flagstaff, AZ; 2106 m). A two-group design, randomized and stratified to baseline Hbmass, sex, and ferritin (>30 μ·L -1 ), was implemented daily as: 1) single dose of 1 × 200 mg (pm only, SINGLE) versus 2) split dose of 2 × 100 mg (am and pm; SPLIT) elemental iron (ferrous fumarate). The Hbmass and venipuncture assessments were completed upon arrival and departure (±2 d) from camp for ferritin, hepcidin, and erythroferrone (ERFE) concentrations. Validated food frequency, GI distress, menstrual blood loss (MBL) and training questionnaires were implemented throughout. Univariate analysis was used to compare Hbmass, with baseline ferritin, dietary iron intake, MBL, and training volume used as covariates. Results: Both conditions increased Hbmass from baseline (P < 0.05), with SINGLE (867.3 ± 47.9 g) significantly higher than SPLIT (828.9 ± 48.9 g) (P = 0.048). The GI scores were worse in SINGLE for weeks 1 and 2 combined (SINGLE, 18.0 ± 6.7 points; SPLIT, 11.3 ± 6.9 points; P = 0.025); however, GI scores improved by week 3, resulting in no between-group differences (P = 0.335). Hepcidin significantly decreased over time (P = 0.043) in SINGLE, with a nonsignificant decrease evident in SPLIT (22%). ERFE significantly decreased in both groups (28.5%; P < 0.05). No between-group differences existed for ERFE, hepcidin, food frequency, MBL, or daily training outcomes (P > 0.05). Conclusions: A single nightly 200-mg dose of elemental iron was superior to a split dose for optimizing Hbmass changes at altitude in runners over an approximately 3-wk training camp.
KW - ELITE RUNNERS
KW - ERYTHROPOIESIS
KW - LONG-DISTANCE
KW - MIDDLE-DISTANCE
KW - SUPPLEMENTATION
UR - http://www.scopus.com/inward/record.url?scp=85062946157&partnerID=8YFLogxK
U2 - 10.1249/MSS.0000000000001847
DO - 10.1249/MSS.0000000000001847
M3 - Article
C2 - 30882751
AN - SCOPUS:85062946157
SN - 0195-9131
VL - 51
SP - 751
EP - 759
JO - Medicine and Science in Sports and Exercise
JF - Medicine and Science in Sports and Exercise
IS - 4
ER -