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Hajj‐Boutros G, Sonjak V, Faust A, Balram S, Lagacé J, St‐Martin P, Divsalar DN, Sadeghian F, Liu‐Ambrose T, Blaber AP, Dionne IJ, Duchesne S, Kontulainen S, Theou O, Morais JA. Myths and Methodologies: Understanding the health impact of head down bedrest for the benefit of older adults and astronauts. Study protocol of the Canadian Bedrest Study. Exp Physiol 2024; 109:812-827. [PMID: 38372420 PMCID: PMC11061626 DOI: 10.1113/ep091473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 01/23/2024] [Indexed: 02/20/2024]
Abstract
Weightlessness during spaceflight can harm various bodily systems, including bone density, muscle mass, strength and cognitive functions. Exercise appears to somewhat counteract these effects. A terrestrial model for this is head-down bedrest (HDBR), simulating gravity loss. This mirrors challenges faced by older adults in extended bedrest and space environments. The first Canadian study, backed by the Canadian Space Agency, Canadian Institutes of Health Research, and Canadian Frailty Network, aims to explore these issues. The study seeks to: (1) scrutinize the impact of 14-day HDBR on physiological, psychological and neurocognitive systems, and (2) assess the benefits of exercise during HDBR. Eight teams developed distinct protocols, harmonized in three videoconferences, at the McGill University Health Center. Over 26 days, 23 participants aged 55-65 underwent baseline measurements, 14 days of -6° HDBR, and 7 days of recovery. Half did prescribed exercise thrice daily combining resistance and endurance exercise for a total duration of 1 h. Assessments included demographics, cardiorespiratory fitness, bone health, body composition, quality of life, mental health, cognition, muscle health and biomarkers. This study has yielded some published outcomes, with more forthcoming. Findings will enrich our comprehension of HDBR effects, guiding future strategies for astronaut well-being and aiding bedrest-bound older adults. By outlining evidence-based interventions, this research supports both space travellers and those enduring prolonged bedrest.
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Affiliation(s)
- Guy Hajj‐Boutros
- Research Institute of McGill University Health CentreMcGill UniversityMontréalQuebecCanada
| | - Vita Sonjak
- Research Institute of McGill University Health CentreMcGill UniversityMontréalQuebecCanada
| | - Andréa Faust
- Research Institute of McGill University Health CentreMcGill UniversityMontréalQuebecCanada
| | - Sharmila Balram
- Research Institute of McGill University Health CentreMcGill UniversityMontréalQuebecCanada
| | - Jean‐Christophe Lagacé
- Faculté des Sciences de l'activité physique, Centre de recherche sur le VieillissementUniversité de SherbrookeSherbrookeQuebecCanada
| | - Philippe St‐Martin
- Faculté des Sciences de l'activité physique, Centre de recherche sur le VieillissementUniversité de SherbrookeSherbrookeQuebecCanada
| | - Donya Naz Divsalar
- Department of Biomedical Physiology and KinesiologySimon Fraser UniversityGreater VancouverBritish ColumbiaCanada
| | - Farshid Sadeghian
- Department of Biomedical Physiology and KinesiologySimon Fraser UniversityGreater VancouverBritish ColumbiaCanada
| | - Teresa Liu‐Ambrose
- Aging, Mobility and Cognitive Neuroscience Laboratory, Department of Physical Therapy, Faculty of MedicineUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Health Research InstituteVancouverBritish ColumbiaCanada
- Centre for Hip Health and MobilityVancouver Coastal Health Research InstituteVancouverBritish ColumbiaCanada
| | - Andrew P. Blaber
- Department of Biomedical Physiology and KinesiologySimon Fraser UniversityGreater VancouverBritish ColumbiaCanada
| | - Isabelle J. Dionne
- Faculté des Sciences de l'activité physique, Centre de recherche sur le VieillissementUniversité de SherbrookeSherbrookeQuebecCanada
| | - Simon Duchesne
- Department of Radiology and Nuclear MedicineUniversité LavalQuebec CityQuebecCanada
- CERVO Brain Research CenterQuebec CityQuebecCanada
| | - Saija Kontulainen
- College of KinesiologyUniversity of SaskatchewanSaskatoonSaskatchewanCanada
| | - Olga Theou
- Physiotherapy and Geriatric MedicineDalhousie UniversityHalifaxNova ScotiaCanada
| | - José A. Morais
- Division of Geriatric Medicine, McGill University Health CentreMcGill UniversityMontréalQuebecCanada
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Schmidt WFJ, Hoffmeister T, Wachsmuth NB, Byrnes WC. The effect of posture and exercise on blood CO kinetics during the optimized carbon monoxide rebreathing procedure. Scand J Clin Lab Invest 2023:1-8. [PMID: 37154842 DOI: 10.1080/00365513.2023.2204402] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
An indispensable precondition for the determination of hemoglobin mass (Hbmass) and blood volume by CO rebreathing is complete mixing of CO in the blood. The aim of this study was to demonstrate the kinetics of CO in capillary and venous blood in different body positions and during moderate exercise. Six young subjects (4 male, 2 female) performed three 2-min CO rebreathing tests in seated (SEA) & supine (SUP) positions as well as during moderate exercise (EX) on a bicycle ergometer. Before, during, and until 15 min after CO rebreathing cubital venous and capillary blood samples were collected simultaneously and COHb% was determined. COHb% kinetics were significantly slower in SEA than in SUP or EX. Identical COHb% in capillary and venous blood were reached in SEA after 5.0 ± 2.3 min, in SUP after 3.2 ± 1.3 min and in EX after 1.9 ± 1.2 min (EX vs. SEA p < .01, SUP vs. SEA p < .05). After 7th min, Hbmass did not differ between the resting positions (capillary: SEA 766 ± 217 g, SUP 761 ± 227 g; venous: SEA 759 ± 224 g, SUP 744 ± 207 g). Under exercise, however, a higher Hbmass (p < .05) was determined (capillary: 823 ± 221 g, venous: 804 ± 226 g). In blood, the CO mixing time in the supine position is significantly shorter than in the seated position. By the 6th minute complete mixing is achieved in either position giving similar Hbmass determinations. CO-rebreathing under exercise conditions, however, leads to ∼7% higher Hbmass values.
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Affiliation(s)
- Walter F J Schmidt
- Department of Sports Medicine/Sports Physiology, University of Bayreuth, Bayreuth, Germany
- Division of Exercise Physiology & Metabolism, University of Bayreuth, Bayreuth, Germany
| | - Torben Hoffmeister
- Department of Sports Medicine/Sports Physiology, University of Bayreuth, Bayreuth, Germany
| | - Nadine B Wachsmuth
- Division of Exercise Physiology & Metabolism, University of Bayreuth, Bayreuth, Germany
| | - William C Byrnes
- Department of Integrative Physiology, University of Colorado, Boulder, CO, USA
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Royal JT, Fisher JT, Mlinar T, Mekjavic IB, McDonnell AC. Validity and reliability of capillary vs. Venous blood for the assessment of haemoglobin mass and intravascular volumes. Front Physiol 2022; 13:1021588. [PMID: 36505074 PMCID: PMC9730879 DOI: 10.3389/fphys.2022.1021588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 11/14/2022] [Indexed: 11/25/2022] Open
Abstract
Objectives: Haemoglobin mass (Hbmass) assessment with the carbon monoxide rebreathing method is a more accurate estimate than other measures of oxygen-carrying capacity. Blood may be collected by several means and differences in the measured variables may exist as a result. The present study assessed the validity and reliability of calculated Hbmass and intravascular volumes obtained from capillary blood (CAP) when compared to venous blood (VEN) draws. Methods: Twenty-two adults performed a carbon monoxide rebreathing procedure with paired VEN and CAP draws at baseline, pre-rebreathing and post-rebreathing (POST). Thirteen of these participants performed this protocol on two occasions to assess the data reliability from both blood sampling sites. In a second experiment, 14 adults performed a 20-min seated and a 20-min supine rest to assess for the effect of posture on haematological parameters. Results: Haemoglobin mass (CAP = 948.8 ± 156.8 g; VEN = 943.4 ± 157.3 g, p = 0.108) and intravascular volume (CAP = 6.5 ± 1 L; VEN = 6.5 ± 0.9 L, p = 0.752) were statistically indifferent, had low bias (Hbmass bias = 14.45 ± 40.42 g, LoA -64.78 g-93.67 g) and were highly correlated between sampling techniques. Reliability analysis demonstrated no difference in the mean change in variables calculated from both sampling sites and good to excellent intraclass correlation coefficients (>0.700), however, typical measurement error was larger in variables measured using CAP (VEN Hbmass TE% = 2.1%, CAP Hbmass TE% = 5.5%). The results indicate that a supine rest prior to the rebreathing protocol would have a significant effect on haemoglobin concentration and haematocrit values compared to a seated rest, with no effect on carboxyhaemoglobin %. Conclusion: The present study demonstrates that CAP and VEN were comparable for the calculation of Hbmass and intravascular volumes in terms of accuracy. However, reduced reliability and increased error in the CAP variables indicates that there are methodological considerations to address when deciding which blood drawing technique to utilise. To reduce this CAP error, increased replicate analyses are required.
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Affiliation(s)
- Joshua T. Royal
- Department of Automation, Biocybernetics, and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia,Jozef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Jason T. Fisher
- Department of Automation, Biocybernetics, and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia,Jozef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Tinkara Mlinar
- Department of Automation, Biocybernetics, and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia,Jozef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Igor B. Mekjavic
- Department of Automation, Biocybernetics, and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia,Department of Biomedical Physiology and Kinesiology, Simon Fraser University Burnaby, Burnaby, BC, Canada
| | - Adam C. McDonnell
- Department of Automation, Biocybernetics, and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia,*Correspondence: Adam C. McDonnell,
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Wang J, Ji Y, Zhou L, Xiang Y, Heinonen I, Zhang P. A New Method to Improve Running Economy and Maximal Aerobic Power in Athletes: Endurance Training With Periodic Carbon Monoxide Inhalation. Front Physiol 2019; 10:701. [PMID: 31244675 PMCID: PMC6562501 DOI: 10.3389/fphys.2019.00701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 05/20/2019] [Indexed: 11/14/2022] Open
Abstract
Background Altitude training stimulates erythropoietin hormone (EPO) release and increases blood hemoglobin (Hb) mass, which may result in improved oxygen (O2) transport capacity. It was hypothesized in the present study that periodic inhalation of carbon monoxide (CO) might elicit similar physiological adaptations compared to altitude training. Methods Twelve male college student athletes, who were well-trained soccer players, participated. They performed a 4-week treadmill-training program, five times a week. Participants were randomly assigned into an experimental group with inhaling CO (INCO) (1 mL/kg body weight for 2 min) in O2 (4 L) before all training sessions and a control group without inhaling CO (NOCO). CO and EPO concentrations in venous blood were first measured acutely at the 1st, 2nd, 4th, 6th, and 8th hour after INCO, and total hemoglobin mass (tHb), running economy and VO2max were measured before and after the 4 weeks training intervention. Results HbCO% increased from 0.7 to 4.4% (P < 0.05) after 1 h of CO inhalation and EPO increased from 1.9 to 2.7 mIU/mL after 4 h post CO inhalation (P < 0.05) acutely before the intervention. After the training, the tHb and VO2max in the INCO group increased significantly by 3.7 and 2.7%, respectively, while no significant differences were observed in the NOCO condition. O2 uptake at given submaximal speeds declined by approximately 4% in the INCO group. Conclusion Acutely, EPO increased sharply post CO inhalation, peaking at 4 h post inhalation. 4-weeks of training with CO inhalation before exercise sessions improved tHb and VO2max as well as running economy, suggesting that moderate CO inhalation could be a new method to improve the endurance performance in athletes.
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Affiliation(s)
- Jun Wang
- The Belt and Road Joint Laboratory for Winter Sports, Department of Exercise Physiology, Beijing Sport University, Beijing, China
| | - Yunhui Ji
- Department of Physical Education, Shanxi Medical University, Taiyuan, China
| | - Li Zhou
- The Belt and Road Joint Laboratory for Winter Sports, Department of Exercise Physiology, Beijing Sport University, Beijing, China
| | - Yang Xiang
- School of Physical Education, Yan'an University, Yan'an, China
| | - Ilkka Heinonen
- Turku PET Centre, Department of Clinical Physiology and Nuclear Medicine, University of Turku, Turku, Finland.,Rydberg Laboratory for Applied Sciences, Department of Environmental and Biosciences, Halmstad University, Halmstad, Sweden
| | - Peng Zhang
- Department of Exercise Science, East Stroudsburg University of Pennsylvania, East Stroudsburg, PA, United States
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Cepeda-Lopez AC, Zimmermann MB, Wussler S, Melse-Boonstra A, Naef N, Mueller SM, Toigo M, Herter-Aeberli I. Greater blood volume and Hb mass in obese women quantified by the carbon monoxide-rebreathing method affects interpretation of iron biomarkers and iron requirements. Int J Obes (Lond) 2019; 43:999-1008. [PMID: 29907846 PMCID: PMC6760578 DOI: 10.1038/s41366-018-0127-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 04/04/2018] [Accepted: 04/22/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND/OBJECTIVE Iron deficiency (ID) is common in overweight and obese individuals (OW/OB) but the mechanism is uncertain. Greater blood volume (BV) in OW/OB may increase hemoglobin (Hb) mass and iron requirements, and confound iron biomarkers by hemodilution. Quantification of BV/PV changes in OW/OB is challenging and a formula to estimate BV/PV based on anthropometric indices would be valuable. In normal weight (NW) and OW/OB women, we aimed at: (1) measure BV and assess whether differences in BV affect concentrations and total circulating mass of Hb and iron biomarkers; (2) develop an algorithm describing BV in OW/OB. SUBJECTS/METHODS In a cross-sectional study, we measured BV in NW, OW, and OB non-anemic women (n = 62) by using the carbon monoxide-rebreathing method, body composition by dual energy X-ray absorptiometry, and iron and inflammatory status. RESULTS OW and OB women had 11 and 16% higher mean BV and PV compared to NW (P < 0.05), respectively. In OW/OB compared to NW, total circulating masses of IL-6, hepcidin, Hb, and sTfR were higher, while total mass of serum iron was lower (for all, P < 0.05). An equation including height, body mass and lean mass to estimate BV in all BMI groups (R2 = 0.76). CONCLUSION An equation based on anthropometric indices provides a good estimate of increased BV in OW/OB women. In OW/OB women, there is an increase in Hb mass that likely increases iron requirements for erythropoiesis and circulating TfR mass. At the same time, higher hepcidin concentrations may lower serum iron mass. Both these mechanisms may increase risk for ID in OW/OB women.
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Affiliation(s)
- Ana C Cepeda-Lopez
- Division of Human Nutrition, Wageningen University (WU), Wageningen, The Netherlands.
- Health Sciences Division, University of Monterrey (UDEM), Monterrey, Mexico.
| | | | - Sophia Wussler
- Laboratory of Human Nutrition, ETH Zürich, Zürich, Switzerland
| | - Alida Melse-Boonstra
- Division of Human Nutrition, Wageningen University (WU), Wageningen, The Netherlands
| | - Nicole Naef
- University Hospital Balgrist, Balgrist Move>Med, Zurich, Switzerland
| | - Sandro Manuel Mueller
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland
- Institute of Human Movement Sciences, ETH Zurich, Zurich, Switzerland
| | - Marco Toigo
- Institute of Human Movement Sciences, ETH Zurich, Zurich, Switzerland
- University Hospital Balgrist, Laboratory for Muscle Plasticity, Zurich, Switzerland
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Tucker MA, Butts CL, Satterfield AZ, Six A, Johnson EC, Ganio MS. Spot Sample Urine Specific Gravity Does Not Accurately Represent Small Decreases in Plasma Volume in Resting Healthy Males. J Am Coll Nutr 2017; 37:17-23. [PMID: 28985131 DOI: 10.1080/07315724.2017.1323692] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND Urine specific gravity (USG) is often used to assess hydration status, particularly around athletic competition, but it is unknown whether high USG is indicative of plasma volume (PV) reduction (i.e., hypohydration). We tested the hypothesis that if high USG is reflective of reduced PV, subsequent fluid ingestion would increase PV. PURPOSE The purpose of this study was to examine 24-hour changes in USG and PV in individuals presenting with high and low spot USG. METHODS Nineteen healthy males were provided food and water over 24 hours with a total water volume of 35 ml·kg-1 body mass. Absolute PV and blood volume (BV), measured using the CO-rebreathe technique, along with USG were measured before and after a 24-hour intervention period. Based on a preintervention morning spot USG, subjects were post hoc assigned to groups according to USG (≤1.020 or >1.020; low and high USG, respectively). RESULTS Despite presenting with an elevated spot USG (1.026 ± 0.004), subsequent fluid ingestion over 24 hours did not lead to changes (∆) in PV (-75 ± 234 ml) or BV (-156 ± 370 ml) in the high USG group (p > 0.05). However, a spot USG after the 24-hour intervention in this group decreased (p = 0.018) to a level indicating improved hydration status (1.017 ± 0.007). In the low USG group, there were no changes in PV (-39 ± 274 ml), BV (-82 ± 396 ml), or USG (0.003 ± 0.007) over the 24-hour fluid intervention (all p > 0.05). CONCLUSIONS Despite a high preintervention USG and subsequent decrease after 24-hour fluid intake, measures of PV and BV were not indicative of this seemingly improved hydration status. This suggests that a highly concentrated spot sample USG and subsequent changes are not accurately representative of PV or BV.
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Affiliation(s)
- Matthew A Tucker
- a Department of Health , Human Performance, and Recreation, University of Arkansas , Fayetteville , Arkansas , USA.,b Georgia Prevention Institute, Augusta University , Augusta , Georgia , USA
| | - Cory L Butts
- a Department of Health , Human Performance, and Recreation, University of Arkansas , Fayetteville , Arkansas , USA
| | - Alf Z Satterfield
- a Department of Health , Human Performance, and Recreation, University of Arkansas , Fayetteville , Arkansas , USA
| | - Ashley Six
- a Department of Health , Human Performance, and Recreation, University of Arkansas , Fayetteville , Arkansas , USA
| | - Evan C Johnson
- a Department of Health , Human Performance, and Recreation, University of Arkansas , Fayetteville , Arkansas , USA.,c Division of Kinesiology and Health , University of Wyoming , Laramie , Wyoming , USA
| | - Matthew S Ganio
- a Department of Health , Human Performance, and Recreation, University of Arkansas , Fayetteville , Arkansas , USA
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Keiser S, Meinild-Lundby AK, Steiner T, Trösch S, Rauber S, Krafft A, Burkhardt T, Hilty MP, Siebenmann C, Wehrlin JP, Lundby C. Detection of blood volumes and haemoglobin mass by means of CO re-breathing and indocyanine green and sodium fluorescein injections. Scandinavian Journal of Clinical and Laboratory Investigation 2017; 77:164-174. [PMID: 28276723 DOI: 10.1080/00365513.2016.1271908] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The main aim of the present study was to quantify the magnitude of differences introduced when estimating a given blood volume compartment (e.g. plasma volume) through the direct determination of another compartment (e.g. red cell volume) by multiplication of venous haematocrit and/or haemoglobin concentration. However, since whole body haematocrit is higher than venous haematocrit such an approach might comprise certain errors. To test this experimentally, four different methods for detecting blood volumes and haemoglobin mass (Hbmass) were compared, namely the carbon monoxide (CO) re-breathing (for Hbmass), the indocyanine green (ICG; for plasma volume [PV]) and the sodium fluorescein (SoF; for red blood cell volume [RBCV]) methods. No difference between ICG and CO re-breathing derived PV could be established when a whole body/venous haematocrit correction factor of 0.91 was applied (p = 0.11, r = 0.43, mean difference -340 ± 612 mL). In contrast, when comparing RBCV derived by the CO re-breathing and the SoF method, the SoF method revealed lower RBCV values as compared to the CO re-breathing method (p < 0.05, r = 0.95, mean difference -728 ± 184 mL). However, compared to the ICG and the SoF methods, the typical error (%TE) and hence reliability of the CO re-breathing method was lower for all measured parameters. Therefore, estimating blood volume compartments by the direct assessment of another compartment can be considered a suitable approach. The CO re-breathing method proved accurate in determining the induced phlebotomy and is at the same time judged easier to perform than any of the other methods.
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Affiliation(s)
- Stefanie Keiser
- a Zurich Center for Integrative Human Physiology , Institute of Physiology, University of Zurich , Zurich , Switzerland
| | - Anne-Kristine Meinild-Lundby
- a Zurich Center for Integrative Human Physiology , Institute of Physiology, University of Zurich , Zurich , Switzerland
| | - Thomas Steiner
- b Swiss Federal Institute of Sports , Magglingen , Switzerland
| | - Severin Trösch
- b Swiss Federal Institute of Sports , Magglingen , Switzerland
| | - Sven Rauber
- a Zurich Center for Integrative Human Physiology , Institute of Physiology, University of Zurich , Zurich , Switzerland
| | - Alexander Krafft
- c Foeto-Maternal Haematology Group, Department of Obstetrics , University Hospital of Zurich , Zurich , Switzerland
| | - Tilo Burkhardt
- c Foeto-Maternal Haematology Group, Department of Obstetrics , University Hospital of Zurich , Zurich , Switzerland
| | | | - Christoph Siebenmann
- e Department of Environmental Physiology, School of Technology and Health , Royal Institute of Technology , Solna , Sweden
| | | | - Carsten Lundby
- a Zurich Center for Integrative Human Physiology , Institute of Physiology, University of Zurich , Zurich , Switzerland
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Cepeda-Lopez AC, Melse-Boonstra A, Zimmermann MB, Herter-Aeberli I. In overweight and obese women, dietary iron absorption is reduced and the enhancement of iron absorption by ascorbic acid is one-half that in normal-weight women. Am J Clin Nutr 2015; 102:1389-97. [PMID: 26561622 DOI: 10.3945/ajcn.114.099218] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 09/25/2015] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Iron deficiency is common in overweight and obese individuals. This deficiency may be due to adiposity-related inflammation that increases serum hepcidin and decreases dietary iron absorption. Because hepcidin reduces iron efflux from the basolateral enterocyte, it is uncertain whether luminal enhancers of dietary iron absorption such as ascorbic acid can be effective in overweight and obese individuals. OBJECTIVE In this study, we compared iron absorption from a meal with ascorbic acid (+AA) and a meal without ascorbic acid (-AA) in women in a normal-weight group (NW) with those in overweight and obese groups combined (OW/OB). DESIGN Healthy, nonanemic women [n = 62; BMI (in kg/m(2)): 18.5-39.9] consumed a stable-isotope-labeled wheat-based test meal -AA and a wheat-based test meal +AA (31.4 mg ascorbic acid). We measured iron absorption and body composition with the use of dual-energy X-ray absorptiometry, blood volume with the use of a carbon monoxide (CO)-rebreathing method, iron status, inflammation, and serum hepcidin. RESULTS Inflammatory biomarkers (all P < 0.05) and hepcidin (P = 0.08) were lower in the NW than in the OW/OB. Geometric mean (95% CI) iron absorptions in the NW and OW/OB were 19.0% (15.2%, 23.5%) and 12.9% (9.7%, 16.9%) (P = 0.049), respectively, from -AA meals and 29.5% (23.3%, 38.2%) and 16.6% (12.8%, 21.7%) (P = 0.004), respectively, from +AA meals. Median percentage increases in iron absorption for -AA to +AA meals were 56% in the NW (P < 0.001) and 28% in OW/OB (P = 0.006). Serum ferritin [R(2) = 0.22; β = -0.17 (95% CI: -0.25, -0.09)], transferrin receptor [R(2) = 0.23; β = 2.79 (95% CI: 1.47, 4.11)], and hepcidin [R(2) = 0.13; β = -0.85 (95% CI: -1.41, -0.28)] were significant predictors of iron absorption. CONCLUSIONS In overweight and obese women, iron absorption is two-thirds that in normal-weight women, and the enhancing effect of ascorbic acid on iron absorption is one-half of that in normal-weight women. Recommending higher intakes of ascorbic acid (or other luminal enhancers of iron absorption) in obese individuals to improve iron status may have a limited effect. This trial was registered at clinicaltrials.gov as NCT01884506.
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Affiliation(s)
- Ana C Cepeda-Lopez
- Division of Human Nutrition, Wageningen University, Wageningen, Netherlands; División de Ciencias de la Salud, Universidad de Monterrey (UDEM), Monterrey, Mexico; and
| | | | - Michael B Zimmermann
- Laboratory of Human Nutrition, Institute of Food, Nutrition and Health, Swiss Federal Institute of Technology Zurich, Zurich, Switzerland
| | - Isabelle Herter-Aeberli
- Laboratory of Human Nutrition, Institute of Food, Nutrition and Health, Swiss Federal Institute of Technology Zurich, Zurich, Switzerland
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Turner G, Richardson AJ, Maxwell NS, Pringle JSM. Comparison of total haemoglobin mass measured with the optimized carbon monoxide rebreathing method across different Radiometer™ ABL-80 and OSM-3 hemoximeters. Physiol Meas 2015; 35:N41-9. [PMID: 25420054 DOI: 10.1088/0967-3334/35/12/n41] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A new Radiometer™ hemoximeter (ABL-80) has recently become available to measure carboxyhaemoglobin concentration for the optimized CO-rebreathing method (oCOR-method). Within the English Institute of Sport (EIS), hemoximeters are used in three different laboratories; therefore, precision and agreement of total haemoglobin mass (tHbmass) determination across sites is essential, and comparison to the previous model OSM-3 is desirable. Six male and one female (age 30 ± 6 years, body mass 78.1 ± 10.6 kg) undertook the oCOR-method. Venous blood (~2 ml) was sampled immediately before and at 7 min during the oCOR-method; with seven replicates from each time point simultaneously analysed on five different Radiometer™ hemoximeters [OSM-3(1), OSM-3(2), ABL-80(1), ABL-80(2) and ABL-80(3)]. There were no differences (p > 0.05) between Δ%HbCO or mean tHbmass analysed with five different hemoximeters (OSM-3(1): 886 ± 167 g; OSM-3(2): 896 ± 160 g: ABL-80(1): 904 ± 157 g; ABL-80(2): 906 ± 163 g: ABL-80(3): 906 ± 162 g). However, the Bland-Altman plot revealed that there was closer agreement between ABL-80 machines for tHbmass than for the OSM-3. The variance (i.e. % error) across replicate samples decreased as the number of samples increased, with the error derived from the 'worse-case' scenario (single samples) being 1.2 to 1.6 fold greater in the OSM-3 than the ABL-80. Although there were no differences in the average tHbmass measured with five different hemoximeters, the new ABL-80 were in better agreement with each other compared to the old OSM-3. Previously, five replicates were required to achieve a low error using the OSM-3; however, three replicates are sufficient with the ABL-80 model to produce an error of ≤ 1% in tHbmass.
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