ObesityNCT05220735
Omega-3 Fatty Acid Supplementation and Fractional Iron Absorption in Obese South African Women
A study testing Omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) in people with Obesity, run by Swiss Federal Institute of Technology at 1 site in South Africa.
Trial summary
In South Africa the prevalence of obesity in women of reproductive age is high; these women also have a high risk for iron deficiency (ID). Obesity is associated with low-grade systemic inflammation, which was shown to increase the expression of hepcidin, leading to a reduction in duodenal iron absorption. Read more about this study
- Who is it for?
- Ages 18 to 35 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Obesity
- What is being tested?
- Omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA)
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 33 participants
- Where
- 1 siteSouth Africa
- Study dates
- 7 Mar 2022to 30 Sep 2023
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 35 years
- Women only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Self-classified women from African descent and of reproductive age (18 - 35 years)
- BMI ≥ 28kg/m2 (indicating obesity)
- Midly- or non-anaemic (Hb ≥11 g/dl)
- Low n-3 LCPUFA status (RBC omega-3 index < 6%)
- Low grade systemic inflammation (HS-CRP ≥ 2 mg/l but ≤ 20 mg/l)
- Be able to read and understand English
Who cannot join
- Treated chronic disease or gastrointestinal disorders
- Regular use of medication (except oral contraceptives, others after approval by the investigator) and women receiving treatment for high blood pressure
- Current consumption of iron or n-3 LCPUFA or ascorbic acid-containing supplements other than the supplements provided (Participants will be asked to discontinue use three weeks prior to enrolment)
- Subject on a weight loss diet or planning to start a weight loss diet during the duration of the study
- Pregnancy or lactation
- Subjects who cannot be expected to comply with the study protocol
Show all 11Show fewer
- Subjects who are smoking
- Difficulty drawing blood due to poor quality veins
- Individuals that have a fear of needles or suffer from vaso-vagal episodes when exposed to blood
- Subjects with fish allergies
- Participants who plan to start or stop the use of contraceptives in the following 4 months.
Trial locations and contacts
1 site in 1 country.
South Africa1 site
Centre of Excellence for Nutrition, North-West University
Potchefstroom
About this study
Official title: Effects of Omega-3 Fatty Acid Supplementation on Fractional Iron Absorption in South African Women Living With Obesity: A Stable Iron Isotope Study
In South Africa the prevalence of obesity in women of reproductive age is high; these women also have a high risk for iron deficiency (ID). Obesity is associated with low-grade systemic inflammation, which was shown to increase the expression of hepcidin, leading to a reduction in duodenal iron absorption. Thus, alleviating the sub-clinical inflammation associated with obesity could improve iron absorption and status. Supplementation with n-3 long-chain polyunsaturated fatty acids (LCPUFA) has been shown to reduce inflammation in obese individuals. A stable iron isotope study will be performed to investigate the effect of n-3 LCPUFA supplementation on fractional iron absorption in obese South African women.
Read the detailed description
Iron deficiency (ID) and iron-deficiency anaemia (IDA) remain a major public health problem in low- and middle-income countries (LMICs). Women of reproductive age are at high risk of developing ID due to loss of iron through menstruation. Furthermore, inadequate iron status at conception and during pregnancy can have detrimental effects on the developing offspring. In addition to ID, the prevalence of obesity is increasing globally, including in LMICs. South Africa is a country with a high prevalence of obesity, especially in women of reproductive age (36 %), and a persistent burden of ID despite a mandatory maize meal and wheat flour fortification programme. Obesity is a condition associated with low-grade systemic inflammation. Inflammation increases the expression of hepcidin, leading to a reduction in duodenal iron absorption. Previous studies have shown that iron absorption differs between normal weight and obese individuals, and that the enhancing effect of ascorbic acid on iron absorption is lower in obese subjects. A possible explanation is the different sites of action of ascorbic acid and hepcidin on the enterocytes: Ascorbic acid enhances iron transport into enterocytes at the luminal side (via divalent metal transporter-1), while hepcidin reduces iron absorption by ferroportin inhibition at the basolateral membrane of the enterocyte. Thus, in obese individuals, an intervention at the basolateral membrane of the enterocyte will be needed. Supplementation with n-3 long-chain polyunsaturated fatty acids (LCPUFA) has been shown to exert cardiometabolic benefits, and to reduce inflammation in obese individuals.
The aim of this study is to investigate the effect of n-3 LCPUFA supplementation on fractional iron absorption in obese South African women of reproductive age. As a secondary objective, this study will determine association between omega-3 fatty acid status, inflammation and iron status in obese South African women. The hypothesises are: 1) fractional iron absorption will increase following n-3 LCPUFA supplementation; 2) iron absorption will further increase in the presence of ascorbic acid following n-3 LCPUFA supplementation.
After screening, apparently healthy, non-anaemic, obese South African women of African descent, aged 18 to 35 years, with low-grade inflammation and a low n-3 LCPUFA status, will receive daily oral fish oil (2.1 g of n-3 LCPUFA) capsules for three months. Iron status indices, inflammatory markers, hepcidin and omega-3 fatty acid index will be assessed at screening. The same variables will be emasured again at baseline and endpoint, in addition to erythrocyte total phospholipid fatty acid composition. Iron absorption will be determined from test meals with and without ascorbic acid using the oral stable isotope method, before (baseline) and after (endpoint) supplementation with n-3 LCPUFA.
- Conditions
- Obesity
- Being tested
- Omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA)
- Keywords
- Fractional iron absorption, Inflammation, Omega-3 fatty acids
- Medical subject headings
- Obesity, Inflammation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA)Dietary supplement
3 three fish oil capsules providing 2.1 g n-3 PUFA; 1.27 g Docosahexanoic acid (DHA) and 0.86 g Eicosapentanoic acid (EPA) capsules.
The absorption study test meals will consist of white bread with butter and honey, 6mg of labeled iron as ferrous sulfate and 300 g of distilled water. The meal will be given on two days without and with ascorbic acid. The test meals without ascorbic acid will contain 6 mg 57Fe as ferrous sulfate whereas the meals containing ascorbic acid will contain 6 mg 58Fe as ferrous sulfate.
| Study group | Role | What they receive |
|---|---|---|
| Experimental | Experimental | Participants will receive three fish oil capsules daily for 14 weeks, and fractional iron absorption from test meals provided without and with ascorbic acid will be determined at baseline and endpoint. Receives: Dietary Supplement: Omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Fractional iron absorption (%)
Fractional iron absorption will be assessed from labeled meals consumed without and with ascorbic acid, before and after intervention with n-3 LCPUFA.
Measured: Change between baseline and 3 months (days 17 and 118)
Secondary outcomes (12)
Haemoglobin (g/dL)
Haemoglobin will be measured in whole blood to determine presence of anaemia.
Measured: Screening, days 1 and 102
Ferritin (µg/L )
Ferritin will be measured in plasma to determine the presence of iron deficiency.
Measured: Screening, days 1 and 102
Soluble transferrin receptor (mg/L)
Soluble transferrin receptor will be measured in plasma to determine the presence of iron deficiency.
Measured: Screening, days 1 and 102
Hepcidin concentration
Hepcidin, a major regulator of iron absorption and influenced by inflammation, will be measured in plasma.
Measured: Screening, days 1 and 102
C-reactive protein (mg/L)
C-reactive protein will be measured in plasma to determine the presence of acute inflammation.
Measured: Screening, days 1 and 102
Alpha-1-acid glycoprotein (g/L)
Alpha-1-acid glycoprotein will be measured in plasma to determine the presence of chronic inflammation.
Measured: Screening, days 1 and 102
Intestinal fatty acid-binding protein
Intesinal fatty acid-binding protein will be measured in plasma as a marker of intestinal damage.
Measured: Screening
Omega-3 fatty acid index (%)
Omega-3 fatty acid index, a measure of eicosapentanoic and docosahexanic acids will be measued in red blood cells.
Measured: Screening
Cytokines (pg/ml)
Cytokines: Interleukin (IL) IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, Interferon gamma and Tumor necrosis factor-beta will be measured in plasma as markers of inflammation.
Measured: Screening, days 1 and 102
Erythrocyte fatty acid composition
Fatty acid composition and status will be determined in erythrocyte phospholipids.
Measured: Days 1 and 102
Lipid mediators (mol/mL or pmol/mL)
The following lipid mediators will be measured in plasma: 17-Hydroxydocosahexanoic acid, 5-, 8-, 11-, 12-, 15- and 18-Hydroxyeicosapentanoic acid (HEPE); 5-, 8-, 11-, 12- and 15-Hydroxyeicosatetraenoic acids (HETE); Prostaglandinds E2, E3 and D2; Protectin D1 and Resolvin D1 and E1.
Measured: Days 1 and 102
Genetic variants in genes associated with fatty acid metabolism
Single nucleotide polymorphism (SNP) analyses of genes involved in fatty acid metabolism will be measured from stored buffy coat.
Measured: Days 1 and 102
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Feb 2022
- Study start7 Mar 2022
- Primary completion10 Mar 2023
- Study completion30 Sep 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for ObesityStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 33 participants (actual)
Sponsor and investigators
- Lead sponsor
- Swiss Federal Institute of Technology
- Sponsor type
- University, hospital or other
- Collaborators
- North-West University, South Africa
- Responsible party
- Principal investigator, Isabelle Herter-Aeberli, Swiss Federal Institute of Technology
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05220735
- Sponsor's protocol ID
- FeMEGA-3
- Status last verified
- Nov 2023
- First submitted
- 6 Jan 2022
- Last updated
- 22 Nov 2023
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Uyoga MA, Baumgartner J, Malan L, Lewies A, Zandberg L, Zeder C, Smuts CM, Herter-Aeberli I. Omega-3 Long-Chain Polyunsaturated Fatty Acid Supplementation Did Not Reduce Inflammation to Improve Iron Absorption in South African Women Living with Overweight or Obesity. J Nutr. 2026 Feb;156(2):101280. doi: 10.1016/j.tjnut.2025.101280. Epub 2025 Dec 26.
PubMed 41456679
Study at a glance
From the registry record, last updated by the sponsor on 22 Nov 2023. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Omega-3 Fatty Acid Supplementation on Fractional Iron Absorption in South African Women Living With Obesity: A Stable Iron Isotope Study
- ClinicalTrials.gov ID
- NCT05220735
- Acronym / sponsor ID
- FeMEGA-3
- Conditions
- Obesity
- Keywords
- Fractional iron absorption, Inflammation, Omega-3 fatty acids
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 33 participants (actual)
- Lead sponsor
- Swiss Federal Institute of TechnologyUniversity, hospital or other
- Collaborators
- North-West University, South Africa
- Study start
- 7 Mar 2022 (actual)
- Primary completion
- 10 Mar 2023 (actual)
- Study completion
- 30 Sep 2023 (actual)
- First posted
- 2 Feb 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
In South Africa the prevalence of obesity in women of reproductive age is high; these women also have a high risk for iron deficiency (ID). Obesity is associated with low-grade systemic inflammation, which was shown to increase the expression of hepcidin, leading to a reduction in duodenal iron absorption. Thus, alleviating the sub-clinical inflammation associated with obesity could improve iron absorption and status. Supplementation with n-3 long-chain polyunsaturated fatty acids (LCPUFA) has been shown to reduce inflammation in obese individuals. A stable iron isotope study will be performed to investigate the effect of n-3 LCPUFA supplementation on fractional iron absorption in obese South African women.
Detailed description
Iron deficiency (ID) and iron-deficiency anaemia (IDA) remain a major public health problem in low- and middle-income countries (LMICs). Women of reproductive age are at high risk of developing ID due to loss of iron through menstruation. Furthermore, inadequate iron status at conception and during pregnancy can have detrimental effects on the developing offspring. In addition to ID, the prevalence of obesity is increasing globally, including in LMICs. South Africa is a country with a high prevalence of obesity, especially in women of reproductive age (36 %), and a persistent burden of ID despite a mandatory maize meal and wheat flour fortification programme. Obesity is a condition associated with low-grade systemic inflammation. Inflammation increases the expression of hepcidin, leading to a reduction in duodenal iron absorption. Previous studies have shown that iron absorption differs between normal weight and obese individuals, and that the enhancing effect of ascorbic acid on iron absorption is lower in obese subjects. A possible explanation is the different sites of action of ascorbic acid and hepcidin on the enterocytes: Ascorbic acid enhances iron transport into enterocytes at the luminal side (via divalent metal transporter-1), while hepcidin reduces iron absorption by ferroportin inhibition at the basolateral membrane of the enterocyte. Thus, in obese individuals, an intervention at the basolateral membrane of the enterocyte will be needed. Supplementation with n-3 long-chain polyunsaturated fatty acids (LCPUFA) has been shown to exert cardiometabolic benefits, and to reduce inflammation in obese individuals.
The aim of this study is to investigate the effect of n-3 LCPUFA supplementation on fractional iron absorption in obese South African women of reproductive age. As a secondary objective, this study will determine association between omega-3 fatty acid status, inflammation and iron status in obese South African women. The hypothesises are: 1) fractional iron absorption will increase following n-3 LCPUFA supplementation; 2) iron absorption will further increase in the presence of ascorbic acid following n-3 LCPUFA supplementation.
After screening, apparently healthy, non-anaemic, obese South African women of African descent, aged 18 to 35 years, with low-grade inflammation and a low n-3 LCPUFA status, will receive daily oral fish oil (2.1 g of n-3 LCPUFA) capsules for three months. Iron status indices, inflammatory markers, hepcidin and omega-3 fatty acid index will be assessed at screening. The same variables will be emasured again at baseline and endpoint, in addition to erythrocyte total phospholipid fatty acid composition. Iron absorption will be determined from test meals with and without ascorbic acid using the oral stable isotope method, before (baseline) and after (endpoint) supplementation with n-3 LCPUFA.
Study design
- Primary purpose
- Prevention
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Experimental | Experimental | Dietary Supplement: Omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA)Participants will receive three fish oil capsules daily for 14 weeks, and fractional iron absorption from test meals provided without and with ascorbic acid will be determined at baseline and endpoint. |
Who may qualify
- Ages
- 18 to 35 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (6 listed)
- Self-classified women from African descent and of reproductive age (18 - 35 years)
- BMI ≥ 28kg/m2 (indicating obesity)
- Midly- or non-anaemic (Hb ≥11 g/dl)
- Low n-3 LCPUFA status (RBC omega-3 index < 6%)
- Low grade systemic inflammation (HS-CRP ≥ 2 mg/l but ≤ 20 mg/l)
Key exclusion criteria (11 listed)
- Treated chronic disease or gastrointestinal disorders
- Regular use of medication (except oral contraceptives, others after approval by the investigator) and women receiving treatment for high blood pressure
- Current consumption of iron or n-3 LCPUFA or ascorbic acid-containing supplements other than the supplements provided (Participants will be asked to discontinue use three weeks prior to enrolment)
- Subject on a weight loss diet or planning to start a weight loss diet during the duration of the study
- Pregnancy or lactation
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA)3 three fish oil capsules providing 2.1 g n-3 PUFA; 1.27 g Docosahexanoic acid (DHA) and 0.86 g Eicosapentanoic acid (EPA) capsules. The absorption study test meals will consist of white bread with butter and honey, 6mg of labeled iron as ferrous sulfate and 300 g of distilled water. The meal will be given on two days without and with ascorbic acid. The test meals without ascorbic acid will contain 6 mg 57Fe as ferrous sulfate whereas the meals containing ascorbic acid will contain 6 mg 58Fe as ferrous sulfate. | Dietary supplement | Experimental |
Primary outcome
Fractional iron absorption (%)
Time frame: Change between baseline and 3 months (days 17 and 118)
Fractional iron absorption will be assessed from labeled meals consumed without and with ascorbic acid, before and after intervention with n-3 LCPUFA.
12 secondary outcomes
Haemoglobin (g/dL)
Time frame: Screening, days 1 and 102
Ferritin (µg/L )
Time frame: Screening, days 1 and 102
Soluble transferrin receptor (mg/L)
Time frame: Screening, days 1 and 102
Hepcidin concentration
Time frame: Screening, days 1 and 102
C-reactive protein (mg/L)
Time frame: Screening, days 1 and 102
Alpha-1-acid glycoprotein (g/L)
Time frame: Screening, days 1 and 102
Intestinal fatty acid-binding protein
Time frame: Screening
Omega-3 fatty acid index (%)
Time frame: Screening
Cytokines (pg/ml)
Time frame: Screening, days 1 and 102
Erythrocyte fatty acid composition
Time frame: Days 1 and 102
Lipid mediators (mol/mL or pmol/mL)
Time frame: Days 1 and 102
Genetic variants in genes associated with fatty acid metabolism
Time frame: Days 1 and 102
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Nov 2023.
- Derived from this study: PubMed 41456679Uyoga MA, Baumgartner J, Malan L, Lewies A, Zandberg L, Zeder C, Smuts CM, Herter-Aeberli I. Omega-3 Long-Chain Polyunsaturated Fatty Acid Supplementation Did Not Reduce Inflammation to Improve Iron Absorption in South African Women Living with Overweight or Obesity. J Nutr. 2026 Feb;156(2):101280. doi: 10.1016/j.tjnut.2025.101280. Epub 2025 Dec 26.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) in people with Obesity, run by Swiss Federal Institute of Technology at 1 site in South Africa.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 11 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 22 Nov 2023. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in South Africa. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Fractional iron absorption (%) (time frame: Change between baseline and 3 months (days 17 and 118)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05220735, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Nov 2023; AzTrials last refreshed its copy on 8 Nov 2026.