Clinical Research Directory

The Effects of Acute Erythropoietin on Hepcidin and Dietary Iron Absorption Following Military-relevant Exercise in Energy Deficit: Pilot Study

Military personnel frequently experience declines in iron status during training and when in the field, which may compromise performance. The overall purpose of this study is to determine why the decline in iron status occurs and potential countermeasures. Participants will be given an acute dose of erythropoietin (EPO) or placebo and will complete a 90-minute load carriage exercise test. Prior to the main trial, this pilot study will determine the optimal approach to assess iron absorption following exercise (red blood cell incorporation or plasma isotope appearance), the percentage of iron incorporated into red blood cells with EPO compared to placebo, and the timing of the intervention.

Dietary Iron Requirements

Dietary Reference Intakes (DRIs) for iron are based on a relatively small number of studies in European populations. This research study will determine iron needs in a representative sample of adults living in the US using the iron isotope dilution technique. Following administration and equilibration of a stable iron isotope, participants will be followed for a 12 week study period. Blood will be collected every 4 weeks and the isotopic composition will be determined. Results will help update dietary iron guidelines making sure they better match the specific needs of the US population.

Impact of a Cricket and Black Soldier Fly Larvae-Fortified Cracker on the Gut Microbiome and Iron Status in Malagasy Schoolchildren

The purpose of this study is to determine the health impacts of consistent consumption of insect-fortified crackers among school-aged children in Madagascar. Specifically, in this RCT, the investigators will assess whether the insect-fortified crackers can improve the health status of Malagasy school children. The investigators' objectives are to: (1) Assess changes in gut microbiome composition that occur after 6 and 14 weeks of cracker consumption through 16S rRNA sequencing. (2) Assess changes in intestinal and systemic inflammation after 6 and 14 weeks of cracker consumption through quantification of fecal calprotectin, lactoferrin, myeloperoxidase (MPO), and alpha-1-antitrypsin (AAT) and circulating pro-inflammatory cytokines. (3) Assess changes in iron status after 14 weeks of cracker consumption through quantification of hemoglobin (Hb), inflammation-adjusted serum ferritin, and soluble transferrin receptor (sTfR).

Zinc and Iron Absorption From Common Beans in Young Adult Women

Fifteen female study participants will be enrolled in a randomized crossover study to measure fractional and total zinc and iron absorption from four common bean (Phaseolus vulgaris) varieties with varying phytate and polyphenolic contents. Phytate, the storage form of phosphorus in plants, and polyphenols, which contribute to the varied colors of common beans, are natural components of the beans and can reduce zinc and iron bioavailability from these foods.

Iron Absorption From Plant Heme Iron

Heme, an iron protoporphyin IX complex, consists of a ferrous ion captured in a porphyrin ring acting as a tetradentate ligand. The unique features of heme iron -its unusually high absorption in foods and its resistance to luminal inhibitors of iron absorption- make it a potentially interesting iron fortificant. This study aims to compare fractional iron absorption from two plant-derived heme iron compounds-iron chlorophyllin and soy hemoglobin-with ferrous sulfate (negative control) and porcine hemoglobin (positive control) in iron-deficient women. All four compounds will be intrinsically labeled with stable iron isotopes. Fractional absorption will be assessed 14 days after test meal administration via erythrocyte iron incorporation. Absorption will be tested in two matrices: water and maize porridge (an inhibitory matrix). Each participant will consume all test conditions in a randomized order, allowing for within-subject comparisons.

Determination of Iron Absorption and Losses in People Living at High Altitude to Investigate the Requirements in This Population Group Using a Newly Developed Technique

Iron is an essential micronutrient responsible for a whealth of biological processes of the human body. Iron plays a fundamental role especially in oxygen transport, by binding to hemoglobin in the blood circulation. Iron intake from the diet needs to be in balance the unavoidable losses that occur daily via different pathways. The recommended daily requirement of iron is based on the balance between absorption and losses and is calculated to maintain a balance so that the absorption equals losses. At higher altitudes, the absorption of iron may be higher due to adaptation mechanisms in response to low oxygen concentration, and to maintain a larger erytroid compartement. However, the long-term effects of altitude on iron balance are unknown. Filling this knowledge gap is important to better understand iron deficiency in populations living at high and moderate altitudes. Therefore, the investigators plan to study people that live at two different altitudes and measure iron absorption and losses over the long term. This will be useful to formulate specific recommendations for this population groups, to expand the knowledge base to better prevent iron deficiency in Switzerland but also worldwide. Participants will be asked to consume a dose of stable iron isotopes. After one year from isotope administration, the isotopes will be equally distributed in all body compartments and any change in the isotope abundance with the normal occurring body iron can be detected. From this point onwards, the investigators can observe the iron turnover and calculate iron absorption and losses per unit of time. At 4 different visits blood samples will be taken from each participant.

Maximizing the Benefits of Iron in Ready-to-Use Therapeutic Foods for Malnourished Children in Kenya

Reports from the Kenya Red Cross Society (KRCS) in Kwale County, southern Kenya, indicate a limited impact of Ready-to-Use Therapeutic Foods (RUTFs) on malnutrition or anemia. The current RUTF formulation may have an excessively high iron content. In severely acutely malnourished (SAM) children, iron cannot be properly absorbed, leading to life-threatening diarrhea. The overall aim of this project is to develop an improved RUTF treatment that addresses acute malnutrition and anemia in children, ensuring both safety and efficacy. Specifically, to assess the impact of malnutrition on fractional iron absorption (FIA) from RUTFs in children, by comparing healthy children to those with acute malnutrition and by tracking changes in FIA in malnourished children over the course of treatment.

The Immediate and Long-term Effects of a Novel Marine-based Iron Supplement in Adult Females

The goal of this study is to identify how well a fish-based iron supplement is absorbed and to learn how many, if any, digestive related side effects are caused by ingesting the supplement.

The Effects of Repeated Operational Stress and Limited Recovery on Resilience Capacity

This longitudinal study will examine the effects of repeated bouts of operational stress and limited recovery on integrated MPS, whole-body protein balance, iron absorption, and aerobic performance. Following baseline characterization measures, active adults (n=24) representative of normal weight phenotype (NW; n=12) and overweight phenotype (OW; n=12) will complete a 48h balance phase preceding two rounds of repeated 72h energy deficit exposure each immediately followed by a 48h recovery phase. NW cutoff will be defined ≤ 22% body fat for males and ≤ 32% body fat for females. OW cutoff will be defined as \>22% body fat for males and \>32% body fat for females. These body composition cutoffs are informed by the maximum allowable percent body fat standards outlined in current Army Regulation 600-9. Additional details for determining % body fat are outlined in the experimental procedures section of the protocol.

Guatemala Biofortified Maize Study

Zinc (Zn) and iron (Fe) deficiencies are common in Guatemala, and maize is a staple food throughout the country. The primary aim of this study is to demonstrate if utilizing nixtamalized biofortified maize has the potential to increase dietary Zn and Fe intake and improve the amount of Zn and Fe absorbed when compared to diets incorporating traditional maize (control). This is a randomized, double blinded, comparison study of biofortified vs control maize prepared as tortillas from nixtamalized masa. This study will enroll up to 56 school aged children (10-14 yrs old) living in agricultural communities in the Western Highlands of Guatemala (28/group x 2 groups). Researchers will utilize Zn and Fe stable isotopes to measure total absorbed Zn and Fe. Participants will be active in the study for 27 days. During this time, they will have anthropometric measurements taken and collect 2 blood samples, 1 stool sample, and 9 urine samples.

Iron Absorption and Requirements in Pregnancy and Lactation

Iron requirements increase significantly during pregnancy. Current recommendations for iron intake in pregnant and lactating women (PLW) are mainly based on factorial estimates and extrapolated from non-PLW. High-quality quantitative data on iron requirements in PLW are lacking, particularly in Sub- Saharan Africa where anaemia and infections are common. The primary objective of this study is to use the stable iron isotope technique to determine iron requirements and assess iron absorption and losses in PLW living in Kenya. In this prospective observational study, we will enrol pregnant women in the first trimester (n = 250) from a previous study cohort (n=1000) who participated in an iron absorption study at least 12 months ago and received the stable iron (Fe) isotope 57Fe. This 57Fe has now distributed and equilibrated throughout the women's body iron. Once enrolled in the present study, following Kenyan guidelines, women will receive standard prenatal care, including routine daily iron and folate supplementation. We will collect venous blood samples in each trimester and at delivery, and during the first 6 months of lactation in the mothers and infants (heel prick samples). To directly assess dietary iron absorption, in a randomly selected subset of women (n=35), oral and intravenous stable iron isotope tracers (54Fe, 58Fe) will be administered in the 2nd and 3rd trimesters.