An interventional study of polyphenols and Placebo in Dysmetabolic Iron Overload Syndrome, Genetic Hemochromatosis and Iron Absorption, sponsored by University Hospital, Clermont-Ferrand. Completed at 1 site in France. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-08-03.
Sponsored by University Hospital, Clermont-Ferrand · Not applicable, Interventional, and Prevention
Dysmetabolic iron overload syndrome and genetic hemochromatosis are frequent causes of iron overload. Polyphenols are efficient iron-chelators. Investigator hypothesize that polyphenol supplementation can reduce iron absorption in iron overload disease. Iron absorption can be studied by the area-under-the-curve of serum iron after iron oral loading. The primary outcome is the decrease of post-prandial serum iron after rich-iron meal, due to polyphenol supplementation.
Iron overload diseases are highly prevalent. Dysmetabolic iron overload syndrome involves 15% of men with metabolic syndrome X. Genetic hemochromatosis is the most common genetic disease in Northern Europe. Both are due to a lack of regulation in iron absorption. To date, there is no nutritional study for those patients.
Polyphenols, particularly flavanols, have shown as good iron-chelating abilities as pharmacological chelators. However, no human study in iron-overload disease have been so far conducted.
The aim of POLYFER-study is to demonstrate that oral polyphenol intake reduces iron absorption in patients with genetic or metabolic iron-overload diseases.
POLYFER is a cross-over randomized controlled trial comparing the effect of polyphenol supplementation versus placebo on iron absorption after loading dose of iron given through a rich-iron meal. Iron absorption will be studied by the area under the curve of serum iron after the meal. Serum iron will be collected after the meal à 0 minute, 30 minutes, 1 hour, 2 hours, 3 hours et 4 hours.
Because of the nycthemeral variations of serum iron, it is essential to obtain a collection of serum iron data in the basal state (after fasting), allowing the calculation for each subject of a "relative" AUC after iron-rich meal with placebo and after iron-rich meal with polyphenols. The endpoint will be the difference between "relative" AUC after meal rich in iron alone and after polyphenols.
In order to improve the underlying mechanism of atherosclerosis which is highly prevalent in those diseases, we will conduct an ancillary study. Recent studies showed interesting results linking some oxylipins levels and inflammation. Investigator will study basal oxylipin level and post-prandial oxylipin level by lipidomic analysis in both diseases.
55 studies on the registry are indexed under Hemochromatosis; 4 are open to participants now.
This study's enrollment of 41 is below the median of 61 across 30 interventional studies indexed under Hemochromatosis.
Browse Hemochromatosis studies →University Hospital, Clermont-Ferrand is the lead sponsor of 859 studies on the registry; 179 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
patients will receive during the meal, 2 capsules of Oligopin® containing 50 mg of polyphenols each. They will take the two capsules simultaneously with a glass of water, after the starter. Each capsule of Oligopin® contains two excipients: 150 mg of maltodextrin and 30 mg of magnesium stearate.
Dietary Supplement: polyphenols
patients will receive during the meal, 2 capsules of placebo, visually identical to Oligopin®. The patient will take the two capsules simultaneously with a glass of water, after the starter. Each capsule of placebo contains two excipients: 218.9 mg of maltodextrin and 1.1 mg of magnesium stearate.
Other: Placebo
After 6 hours of fasting, each patient will eat a complete meal course, containing 40 mg of iron, at two different days (wash-out period: 3 days between each meal). During each meal, each patient will receive, two capsules containing polyphenols or two placebo capsules (cross-over methodology). The meal in which each patient will receive either polyphenol or placebo will be randomized. The diet consists of : * Starter: duck gizzard salad. * Main course: black pudding and pasta. * French cheese. * Fruits: kiwi fruit. This diet contain approximately 40 mg of iron, with low polyphenol intake. Patients will be asked to eat the whole gizzard and black pudding to ensure the highest iron intake. At the end of the meal, blood samples will be collected at 0 minute, 30 minutes, 1 hour, 2 hours, 3 hours and 4 hours, to assess serum iron level, in order to measure the area under the curve of iron kinetic.
After 6 hours of fasting, each patient will eat a complete meal course, containing 40 mg of iron, at two different days (wash-out period: 3 days between each meal). During each meal, each patient will receive, two capsules containing polyphenols or two placebo capsules (cross-over methodology). The meal in which each patient will receive either polyphenol or placebo will be randomized. The diet consists of : * Starter: duck gizzard salad. * Main course: black pudding and pasta. * French cheese. * Fruits: kiwi fruit. This diet contain approximately 40 mg of iron, with low polyphenol intake. Patients will be asked to eat the whole gizzard and black pudding to ensure the highest iron intake. At the end of the meal, blood samples will be collected at 0 minute, 30 minutes, 1 hour, 2 hours, 3 hours and 4 hours, to assess serum iron level, in order to measure the area under the curve of iron kinetic.
Decrease of post-prandial iron absorption after dietary polyphenol supplementation
decrease of intestinal iron absorption after standardized oral loading dose through rich-iron meal, expressed by area-under-the-curve of serum iron, due to concomitant administration of a single dose of dietary polyphenos (nutrient complement) versus placebo administration. This outcome is a quantitative variable, treated and analysed as such.
Time frame: at day 3
Post-prandial changes of circulating oxylipin in iron overload diseases after iron-rich meal and effects of polyphenols supplementation
comparison of oxylipin levels, through lipidomic analyses by spectrophotometry
Time frame: at day 1 (fasting versus 3 hours after rich-iron meal, versus 3 hours after rich-iron meal with polyphenol supplementation)
Comparison of oxylipin levels between DIOS, genetic hemochromatosis and healthy subjects after 6 hours of fasting.
comparison of oxylipin levels, through lipidomic analyses by spectrophotometry. Healthy subjects datas comes from a previous study (MEPHISTO).
Time frame: at baseline
This study is completed, as verified in Jul 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Polyphenols
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