Brief Title
Effect of Altitude on Iron Absorption in Iron Depleted Women
Official Title
Effect of Altitude on Iron Absorption in Iron Depleted Women
Brief Summary
One of the most common nutritional deficiencies worldwide is iron deficiency. Iron deficiency
is considered the main cause of anaemia in developing countries, including those in South
America. The most recent surveys report that the prevalence of anaemia is as high as, 40 and
25% in Peru.
Populations living at higher altitudes may have higher iron requirements, as body iron is
naturally increased in long-term high-altitude residents to compensate for the lower oxygen
in the air at high altitudes. However, the effects of chronic exposure to high altitude on
iron status, body iron compartments and dietary iron requirements are incompletely
understood.
The primary objective of the proposed research is to determine iron bioavailability of iron
from biofortified potatoes at different altitudes in populations of Andean descent. Human
trials will be undertaken with volunteers in the Huancavelica region of Peru (elevation: 3676
meters) as well as in Lima (elevation close to sea level). The aim is to assess the effect of
altitude on the absorption from a promising iron biofortified potato cultivar. These trials
require incorporation of iron stable isotopes into the meals of the bio fortified potato and
the analysis of the isotopes in subsequent blood (red blood cells) samples. Stable iron
istotopes are considered the golden standard to assess human iron absorption and can be
safely used as tracer substances in humans.
The objective of the study is to compare, in volunteer females of childbearing age, the
bioavailability of iron from bio-fortified potatoes in two locations of different altitudes
and quantify the effect of altitude on iron bioavailability from a potato meal consumed over
5 consecutive days.
Detailed Description
Populations living at higher altitudes may have higher iron requirements, as body iron is
naturally increased in long-term high-altitude residents to compensate for the lower oxygen
partial pressure. A residence altitude of 3600 masl implies an increase in Hemoglobin of ≈30
g Hb/l, which would correspond, in a 60 Kg woman to an increase of ≈500 mg red blood cell
iron. Early studies in Bolivia have suggested decreased iron stores in women living at
altitudes >3000 masl, compared to their counterparty living below 3000 masl .
The short-term exposure to high altitudes has profound impacts on iron metabolism. The lower
oxygen partial pressure increases the rate of red blood cell synthesis, which is reflected in
decrease in iron status parameters such as serum iron, serum ferritin, and an increase in
erythropoietin and erythroferrone which in turn downregulate hepcidin, the master regulator
of systemic iron metabolism , affecting iron release from stores and dietary iron absorption
. In addition, intracellular oxygen sensors, the prolyl hydrolases (PHD's), stabilize hypoxia
inducible factors (HIF-1α and HIF2-α) critically controlling transcriptional regulators such
as dimetal transporter-1 (DMT-1) responsible for apical iron absorption in enterocytes .
Early studies in Peru by Huff et al. showed marked short-term increases of serum iron
incorporation in red blood cells in subjects native from Lima (sea level) during
acclimatization at Morococha, at 4540 masl. The opposite was the case in Morococha natives
during acclimatization in Lima, as they had a decreased rate of plasma iron transfer to red
blood cells . Notably however, during the short duration of the study (10 days) no marked
change in red cell volume, hemoglobin or red cell mass could be detected.
Despite these well-described biologic mechanisms and short-term effects on physiological
markers of iron status, the effects of chronic exposure to high altitude on iron status, body
iron compartments and dietary iron requirements are incompletely understood. Genetic factors
as reflected by different ethnicities are considered to play a large role in altitude-induced
adaptations in iron metabolism .
A recent large study (n=71798) conducted in young male and iron replete Swiss army conscripts
suggests a steady increase in hemoglobin and ferritin with increasing altitude, an increase
that was detectable with each 300 masl increase, starting with as low as 300 masl of
altitude. The authors also suggested that in this population, serum ferritin rose with
altitude, independently from the increase in hemoglobin , suggesting a separate biological
mechanism driving iron stores with increasing altitude. This data contrasts with data from
Bolivia in apparently healthy women of reproductive age, where body iron stores were
decreased at altitudes >3000 masl , compared to women living at lower altitudes (<3000 masl),
suggesting that at high altitude, iron availability may be a limiting factor for optimal iron
stores and for anemia prevention. More research is therefore needed on the determinants of
iron balance in function of altitude, namely the interplay between dietary iron absorption,
iron status, and iron status markers.
The primary objective of the proposed research is to determine iron bioavailability of iron
from biofortified potatoes at different altitudes in populations of Andean descent. Human
trials will be undertaken with volunteers in the Huancavelica region of Peru (elevation: 3676
meters) as well as in Lima (elevation close to sea level). The aim is to assess the effect of
altitude on the absorption from a promising iron biofortified potato cultivar. These trials
require incorporation of iron stable isotopes into the meals of the bio fortified and the
analysis of the isotopes in subsequent blood (red blood cells) samples.
Study Type
Interventional
Primary Outcome
Iron absorption
Secondary Outcome
Serum ferritin (SF)
Condition
Iron Deficiency Anemia
Intervention
Biofortified potato, not genetically modified
Study Arms / Comparison Groups
Biofortified potato
Description: 500 g of biofortified, cooked potato, comsumed over 5 consecutive days (500g for each day, for a total of 2500 g of cooked potato). Potato meals will be labelled with a total of 3 mg 57FeSO4.
Publications
* Includes publications given by the data provider as well as publications identified by National Clinical Trials Identifier (NCT ID) in Medline.
Recruitment Information
Recruitment Status
Other
Estimated Enrollment
80
Start Date
August 20, 2022
Completion Date
March 31, 2023
Primary Completion Date
November 15, 2022
Eligibility Criteria
Inclusion Criteria:
- Healthy women aged 18-40 years
- Able to understand study requirements and provide written informed consent.
- Huancavelica study site: having been a Huancavelica or Peruvian highlands resident in
the last 5 years, with at least one parent being from Huancavelica
- Lima study site: having been a Lima resident in the last 5 years, with origins and at
least one parent being from the Peruvian highlands (>3000 masl)
- Serum ferritin at screening < 30 microgram/L
Exclusion Criteria:
- Illness that affects the nutritional status or food intake: gastrointestinal or renal
problems; self-reported metabolic disease based on prior diagnosis, or a prior
screening questionnaire.
- Pregnancy (positive urine test).
- Currently breastfeeding.
- Allergy to any ingredients of the test meal.
- C-reactive protein >5mg/100ml (representing inflammation)
- Smoker (>1 cigarette per day)
Gender
Female
Ages
18 Years - 40 Years
Accepts Healthy Volunteers
Accepts Healthy Volunteers
Contacts
Diego Moretti, PhD, +41 (0)44 512 09 20, [email protected]
Location Countries
Peru
Location Countries
Peru
Administrative Informations
NCT ID
NCT05500014
Organization ID
2022/01
Responsible Party
Sponsor
Study Sponsor
Swiss Distance University of Applied Sciences
Collaborators
ETH Zurich (Switzerland)
Study Sponsor
Diego Moretti, PhD, Principal Investigator, Swiss Distance University of Applied Sciences
Verification Date
October 2022