An interventional study of Normobaric hypoxia (NH) and Normobaric normoxia (NN) in Obesity (Disorder), sponsored by Pennington Biomedical Research Center. Recruiting at 1 site in United States. Open to participants aged 22 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-04-21.
Sponsored by Pennington Biomedical Research Center · Not applicable, Interventional, and Treatment
Declines in iron status are common in those with obesity and may be due to obesity-related chronic inflammation; however, the effects of reducing inflammation following diet-induced weight loss on iron metabolism are poorly understood. Low environmental oxygen exposure increases dietary iron absorption and availability to supply iron for erythropoiesis but has not yet been tested in the context of weight loss. This study is designed to investigate diet-induced weight loss (inflammation reduction) and overnight low oxygen exposure (erythropoiesis stimulating agent) as strategies to improve dietary iron absorption in obesity.
Those with obesity are at increased risk for iron deficiency, which can worsen obesity-related comorbidities and add considerably to national health-care budgets. Declines in iron status in those with obesity may be due to adiposity-related inflammation. Adipokines, such as interleukin 6, increase hepcidin, an iron regulatory hormone secreted by the liver that functions to reduce iron absorption and iron availability. Elevated hepcidin and reduced dietary iron absorption may explain why those with obesity are more susceptible to iron deficiency and more resistant to treatment with iron supplements. However, the effects of reducing inflammation on iron absorption in those with obesity are poorly understood. In addition, low environmental oxygen exposure may be an alternative to optimize iron metabolism in obesity since hypoxia stimulates the synthesis of erythropoietin, which strongly suppresses hepcidin and increases iron absorption. The proposed study aims to capitalize on the ongoing Low Oxygen and Weight Status (LOWS) randomized, double-blind, parallel-arm, controlled-feeding trial (R01DK127162; Berryman) to understand the mechanism by which obesity increases risk for iron deficiency and potential countermeasures. In LOWS, adults with obesity are randomized to 8 weeks of controlled-feeding energy restriction (-500 kcal/day) plus intermittent exposure to normobaric hypoxia (8 h/night, 15% FiO2) or normoxia (8 h/night, 21% FiO2) using a commercially available, in-home tent system. This study aims at assessing dietary iron absorption at baseline and following 8 weeks of energy restriction in normoxia or intermittent hypoxia. Results of this project will serve as a foundation to the development of interventions to prevent and treat declines in iron status in obesity.
Exclusion Criteria:
8 weeks of overnight exposure (8 hrs/night) to NH conditions (\~15% oxygen; achieved with nitrogen dilution, equivalent to \~8500 feet elevation) using a commercially available tent and generator system (Hypoxico, Inc., New York, NY).
Other: Normobaric hypoxia (NH)
8 weeks of overnight exposure (8 hrs/night) to NN conditions (\~21% oxygen; sea level) using a commercially available tent and generator system (Hypoxico, Inc., New York, NY).
Other: Normobaric normoxia (NN)
Low oxygen exposure to mimic \~8500 feet elevation (experimental)
Normal oxygen exposure to mimic sea level conditions (sham comparator).
Change in iron absorption
Fractional iron absorption will be measured during the baseline weight maintenance phase (day -7) and at the end of the study (day 42). Change in fractional iron absorption will be calculated as: fractional iron absorption on day 42 - fractional iron absorption on day -7.
Time frame: 7 weeks
Plan to share: No
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Pennington Biomedical Research Center