Dysmetabolic Iron Overload Syndrome: Raised Ferritin With Metabolic Syndrome


A ferritin result above the laboratory range is a common finding on a routine blood test (13% of middle-aged adults in one Austrian cohort), and the most common setting for it is not inherited iron disease but excess weight, high blood pressure, abnormal blood fats, high blood sugar or a fatty liver. In 1997 a French team described people in this setting whose livers also held extra iron, a pattern later named dysmetabolic iron overload syndrome (DIOS). This page sets out how the research defines it, how often it turns up, how it differs from inherited hemochromatosis, what the leading explanations are and how strong each one is, and what happened when doctors tried removing blood to treat it, including the trials that found no benefit. The Hemochromatosis page covers the inherited disease and the Iron Overload: Liver Problems page covers how iron injures the liver; this page stays with the metabolic form.


Table of Contents

  1. What the Name Describes
  2. How Common It Is
  3. How It Differs From HFE Hemochromatosis
  4. What a High Ferritin Does and Does Not Mean
  5. Proposed Mechanisms, Sorted by Type of Evidence
  6. Findings Reported Alongside It
  7. Bloodletting Trials: Results in Both Directions
  8. What Happens After Iron Is Removed
  9. Diet, Weight and Lifestyle Findings
  10. What Is Not Known
  11. Key Research Papers
  12. Connections
  13. Featured Videos

What the Name Describes

The syndrome was first described in The Lancet in 1997. Moirand and colleagues in Rennes, France, studied 65 people who had unexplained iron in the liver and a normal transferrin saturation (the share of the blood's iron-carrying protein that is loaded with iron). Their median liver iron concentration was 65 µmol/g of dry liver, against a normal value below 36 µmol/g; their median ferritin was 566 µg/L; and their median transferrin saturation was 32%. Ninety-five per cent had one or more of obesity, raised blood fats, abnormal glucose handling or high blood pressure. The authors called it "a new non-HLA-linked iron-overload syndrome" and wrote that it "suggests a link between iron excess and metabolic disorders".

Two years later the same group described 161 people with unexplained liver iron who did not carry two copies of the C282Y variant of the HFE gene. Most (94%) had features of the insulin-resistance syndrome, defined in that study as a body mass index above 25, diabetes or raised blood fats. Liver iron ranged from 38 to 332 µmol/g (median 90). Transferrin saturation was raised in 35% of them, with a median of 42%. The authors called the pattern insulin resistance-associated hepatic iron overload.

A 2017 review by three of the Rennes researchers gives the definition most later papers repeat. Dysmetabolic iron overload syndrome is:

A related label, dysmetabolic hyperferritinemia, describes the raised ferritin and the metabolic features without proof of extra iron in the liver. A 2020 review asked whether the two are "two related conditions or different entities" and noted that their clinical presentation "overlaps almost completely". In 2023 a multidisciplinary global panel of researchers published a consensus statement proposing an updated definition and a provisional staging system for metabolic hyperferritinemia (a raised ferritin with metabolic dysfunction). A 2024 validation study applied it using three ferritin grades: grade 1 from 200 µg/L in women or 300 µg/L in men up to 550 µg/L; grade 2 from 550 to 1,000 µg/L; and grade 3 above 1,000 µg/L. The panel wrote that "validated criteria for the non-invasive diagnosis of metabolic hyperferritinaemia and the staging of iron overload are still lacking".

An Italian biopsy study of 81 people with unexplained liver iron, published in 2008, found that two or more features of metabolic syndrome together with a fatty liver marked out a group with moderate iron overload, iron sitting mainly in the liver's lining (sinusoidal) cells, and a normal transferrin saturation. People with a transferrin saturation of 60% or more had heavier iron loading, few or no metabolic abnormalities and a pattern that resembled hemochromatosis.

How Common It Is

Counts vary widely, mainly because studies define the condition differently and few measure liver iron directly.

The 2020 review calls dysmetabolic iron overload syndrome "the most frequent iron overload condition". The Basque studies, described further down, found that many people with a high ferritin and metabolic syndrome had little or no measurable extra liver iron, which is why the raised-ferritin counts above are larger than the number with true iron overload.

How It Differs From HFE Hemochromatosis

Hereditary hemochromatosis, mostly caused by two copies of the C282Y variant of the HFE gene, is described on the Hemochromatosis page. The studies on this page compare the two conditions in four ways.

One finding cuts the other way. A 2001 study of 56 phlebotomised patients with insulin resistance-associated iron overload reported that they gave up a similar total amount of iron as C282Y homozygotes, while their ferritin was three times higher. The authors concluded that ferritin overestimated their iron stores. A 2015 case-control study measured the iron removed by bloodletting: 2.5 g in 12 people with dysmetabolic iron overload syndrome against 0.8 g in 12 overweight people with normal ferritin.

The two conditions also look alike in some respects. In a 2024 study of 20 people with each condition, the pattern of oxidised fat molecules in the blood (oxylipins) did not separate the two groups, apart from one molecule, 20-hydroxyeicosatetraenoic acid, which was higher in the metabolic group and tracked with high blood pressure.

What a High Ferritin Does and Does Not Mean

Ferritin is the protein that stores iron inside cells, and a small amount of it circulates in the blood. Its level tracks iron stores, but it also rises for reasons that have nothing to do with extra iron. The studies found that a high ferritin in someone with metabolic features is often not a sign of iron overload.

For this reason the Liver Problems page describes transferrin saturation as the more specific test, and the studies above confirmed extra liver iron with magnetic resonance imaging or biopsy. The Ferritin Test and Iron Panel pages explain the blood tests themselves.

Proposed Mechanisms, Sorted by Type of Evidence

Why iron would build up in people with insulin resistance is still debated. The 2017 Rennes review calls it "a multifactorial and dynamic process triggered by an excessively rich diet, facilitated by environmental and genetic cofactors and implying a cross-talk between the liver and visceral adipose tissue". That is the authors' interpretation, not a tested finding. The pieces below are grouped by the kind of evidence behind them.

Hepcidin is raised, not lowered (measured in people)

Hepcidin is the liver hormone that limits how much iron the gut absorbs and how much iron storage cells release; the Iron Absorption and the Hepcidin Gate animation shows how it works. In hemochromatosis hepcidin is too low. In the metabolic syndrome the human measurements point the other way:

Hepcidin resistance (a small challenge study in people)

A 2016 Milan study gave an oral iron dose to 18 people with dysmetabolic iron overload syndrome, 18 with fatty liver, 23 healthy people and 10 with hemochromatosis. The metabolic group made more hepcidin than any other group, but that hepcidin spike was less able to hold down the rise in transferrin saturation early in the test. The authors proposed "a hepcidin resistance state" and wrote that "further studies are required" to find the molecular cause.

Inflammation and fat tissue (human tissue and laboratory work)

In liver and fat tissue from severely obese patients, hepcidin was made in fat tissue as well as in the liver, and more of it was made in the fat of obese patients. Fat-tissue hepcidin tracked with interleukin-6 and C-reactive protein, two markers of inflammation, and interleukin-6 raised hepcidin in fat tissue in the laboratory. Sixty-eight per cent of these patients had a low transferrin saturation. The authors called hepcidin "a proinflammatory adipokine" and linked it to the low blood iron of inflammation in obesity, not to iron build-up.

Insulin resistance (association in people)

The tie to insulin resistance comes mainly from how often the two occur together: 94% of Mendler's patients and 95% of Moirand's had metabolic features. In the absorption study, iron absorption fell as insulin resistance rose. These are associations. Whether insulin resistance causes the iron build-up, the iron worsens insulin resistance, or both come from a shared cause is not settled. The bloodletting trials below were partly a test of the second idea.

Diet (animal work and review opinion)

The "excessively rich diet" trigger in the Rennes review is an interpretation. No human study read for this page tested it.

Findings Reported Alongside It

These are associations from observational studies and do not show that the iron caused the finding.

Bloodletting Trials: Results in Both Directions

Removing blood (phlebotomy or venesection) is the standard treatment for hemochromatosis. Whether it helps people with metabolic iron excess has been tested many times. The results split by study design: uncontrolled and matched studies were mostly positive, while the two largest randomized trials were null.

Studies that reported a benefit

Studies that found no benefit

The 2018 analysis is the larger of the two meta-analyses (nine studies and 820 patients, against four studies and 438). The 2017 Rennes review states that phlebotomy "cannot be currently considered as a valuable option" in this syndrome, and the 2023 consensus panel found "no clear evidence of a benefit for iron depletion therapy". By contrast, the 2001 Rennes paper and the 2020 Milan review regard bloodletting with diet and lifestyle change as a treatment approach. A 2019 systematic review stated that phlebotomy works only where iron sits in the liver cells themselves, not where a high ferritin reflects inflammation. In the 2026 Spanish review of 179 people in a bloodletting programme, metabolic syndrome with a high ferritin accounted for 33% of them. Only 48% fitted the authors' standard of hemochromatosis with significant liver iron, and the authors wrote that "a high percentage do not benefit from it".

Bloodletting has measured downsides in these trials: fatigue in a quarter of bled patients in the largest trial, and a small weight gain. The Berberine and Iron Overload page also reports the 274-person trial.

What Happens After Iron Is Removed

A Rennes follow-up study traced 58 patients who had finished bloodletting between 1998 and 2003 and had no treatment afterwards. They had started with a mean liver iron of 80 µmol/g and had 2.2 g of iron removed. After a mean of 71 months, 64% had iron overload again. The ferritin level at diagnosis was the only factor linked to recurrence. The authors suggested periodic follow-up to find those who might need maintenance treatment.

Diet, Weight and Lifestyle Findings

In the absorption studies, people with the syndrome absorbed less iron than controls and far less than people with hemochromatosis. No study read for this page tested a diet aimed at cutting iron absorption in them apart from the procyanidin meal; the diet and lifestyle findings concern weight and metabolic health. The Metabolic Syndrome, Insulin Resistance and Fatty Liver Disease pages cover that research.

What Is Not Known

Key Research Papers

  1. Moirand R, Mortaji AM, Loréal O, Paillard F, Brissot P, Deugnier Y. A new syndrome of liver iron overload with normal transferrin saturation. Lancet. 1997;349(9045):95-7. PubMed PMID: 8996422
  2. Mendler MH, Turlin B, Moirand R, Jouanolle AM, Sapey T, Guyader D, et al. Insulin resistance-associated hepatic iron overload. Gastroenterology. 1999;117(5):1155-63. PubMed PMID: 10535879
  3. Riva A, Trombini P, Mariani R, Salvioni A, Coletti S, Bonfadini S, et al. Revaluation of clinical and histological criteria for diagnosis of dysmetabolic iron overload syndrome. World J Gastroenterol. 2008;14(30):4745-52. PubMed PMID: 18720534
  4. Deugnier Y, Bardou-Jacquet É, Lainé F. Dysmetabolic iron overload syndrome (DIOS). Presse Med. 2017;46(12 Pt 2):e306-e311. PubMed PMID: 29169710
  5. Valenti L, Corradini E, Adams LA, Aigner E, Alqahtani S, Arrese M, et al. Consensus Statement on the definition and classification of metabolic hyperferritinaemia. Nat Rev Endocrinol. 2023;19(5):299-310. PubMed PMID: 36805052
  6. Chen LY, Chang SD, Sreenivasan GM, Tsang PW, Broady RC, Li CH, et al. Dysmetabolic hyperferritinemia is associated with normal transferrin saturation, mild hepatic iron overload, and elevated hepcidin. Ann Hematol. 2011;90(2):139-43. PubMed PMID: 20721554
  7. Ruivard M, Lainé F, Ganz T, Olbina G, Westerman M, Nemeth E, et al. Iron absorption in dysmetabolic iron overload syndrome is decreased and correlates with increased plasma hepcidin. J Hepatol. 2009;50(6):1219-25. PubMed PMID: 19398238
  8. Rametta R, Dongiovanni P, Pelusi S, Francione P, Iuculano F, Borroni V, et al. Hepcidin resistance in dysmetabolic iron overload. Liver Int. 2016;36(10):1540-8. PubMed PMID: 26998752
  9. Martinelli N, Traglia M, Campostrini N, Biino G, Corbella M, Sala C, et al. Increased serum hepcidin levels in subjects with the metabolic syndrome: a population study. PLoS One. 2012;7(10):e48250. PubMed PMID: 23144745
  10. Bekri S, Gual P, Anty R, Luciani N, Dahman M, Ramesh B, et al. Increased adipose tissue expression of hepcidin in severe obesity is independent from diabetes and NASH. Gastroenterology. 2006;131(3):788-96. PubMed PMID: 16952548
  11. Jézéquel C, Lainé F, Laviolle B, Kiani A, Bardou-Jacquet E, Deugnier Y. Both hepatic and body iron stores are increased in dysmetabolic iron overload syndrome. A case-control study. PLoS One. 2015;10(6):e0128530. PubMed PMID: 26030828
  12. Castiella A, Urreta I, Zapata E, Zubiaurre L, Alústiza JM, Otazua P, et al. Liver iron concentration in dysmetabolic hyperferritinemia: Results from a prospective cohort of 276 patients. Ann Hepatol. 2020;19(1):31-35. PubMed PMID: 31587985
  13. Castiella A, Zapata E, Zubiaurre L, Iribarren A, Alústiza JM, Otazua P, et al. Liver iron concentration is not raised in patients with dysmetabolic hyperferritinemia. Ann Hepatol. 2016;15(4):540-544. PubMed PMID: 28869748
  14. Castiella A, Zapata E, Zubiaurre L, Ma Alustiza J, De Juan MD, Iribarren A, et al. Impact of H63D mutations, magnetic resonance and metabolic syndrome among outpatient referrals for elevated serum ferritin in the Basque Country. Ann Hepatol. 2015;14(3):333-9. PubMed PMID: 25864213
  15. Gensluckner S, Wernly B, Koutny F, Strebinger G, Zandanell S, Stechemesser L, et al. Prevalence and Characteristics of Metabolic Hyperferritinemia in a Population-Based Central-European Cohort. Biomedicines. 2024;12(1):207. PubMed PMID: 38255312
  16. Souza M, Lima LCV, Villela-Nogueira CA. Prevalence and Characteristics of Hyperferritinemia in Metabolic Dysfunction-Associated Steatotic Liver Disease: A Meta-Analysis. Liver Int. 2026;46(4):e70569. PubMed PMID: 41873565
  17. Moris W, Verhaegh P, Jonkers D, Deursen CV, Koek G. Hyperferritinemia in Nonalcoholic Fatty Liver Disease: Iron Accumulation or Inflammation? Semin Liver Dis. 2019;39(4):476-482. PubMed PMID: 31330553
  18. Kowdley KV, Belt P, Wilson LA, Yeh MM, Neuschwander-Tetri BA, Chalasani N, et al. Serum ferritin is an independent predictor of histologic severity and advanced fibrosis in patients with nonalcoholic fatty liver disease. Hepatology. 2012;55(1):77-85. PubMed PMID: 21953442
  19. Whitfield JB, Zhu G, Heath AC, Powell LW, Martin NG. Effects of alcohol consumption on indices of iron stores and of iron stores on alcohol intake markers. Alcohol Clin Exp Res. 2001;25(7):1037-45. PubMed PMID: 11505030
  20. Risca G, Pelucchi S, Mariani R, Botti M, Capitoli G, Di Gennaro F, et al. Transferrin Saturation and Serum Ferritin Are Main Predictors of Liver Iron Content in Subjects With Hyperferritinemia. Clin Gastroenterol Hepatol. 2026;24(1):141-149.e6. PubMed PMID: 40398831
  21. Lainé F, Ruivard M, Loustaud-Ratti V, Bonnet F, Calès P, Bardou-Jacquet E, et al. Metabolic and hepatic effects of bloodletting in dysmetabolic iron overload syndrome: A randomized controlled study in 274 patients. Hepatology. 2017;65(2):465-474. PubMed PMID: 27685251
  22. Adams LA, Crawford DH, Stuart K, House MJ, St Pierre TG, Webb M, et al. The impact of phlebotomy in nonalcoholic fatty liver disease: A prospective, randomized, controlled trial. Hepatology. 2015;61(5):1555-64. PubMed PMID: 25524401
  23. Valenti L, Fracanzani AL, Dongiovanni P, Rovida S, Rametta R, Fatta E, et al. A randomized trial of iron depletion in patients with nonalcoholic fatty liver disease and hyperferritinemia. World J Gastroenterol. 2014;20(11):3002-10. PubMed PMID: 24659891
  24. Valenti L, Fracanzani AL, Dongiovanni P, Bugianesi E, Marchesini G, Manzini P, et al. Iron depletion by phlebotomy improves insulin resistance in patients with nonalcoholic fatty liver disease and hyperferritinemia: evidence from a case-control study. Am J Gastroenterol. 2007;102(6):1251-8. PubMed PMID: 17391316
  25. Valenti L, Moscatiello S, Vanni E, Fracanzani AL, Bugianesi E, Fargion S, et al. Venesection for non-alcoholic fatty liver disease unresponsive to lifestyle counselling--a propensity score-adjusted observational study. QJM. 2011;104(2):141-9. PubMed PMID: 20851820
  26. Guillygomarc'h A, Mendler MH, Moirand R, Lainé F, Quentin V, David V, et al. Venesection therapy of insulin resistance-associated hepatic iron overload. J Hepatol. 2001;35(3):344-9. PubMed PMID: 11592595
  27. Lainé F, Reymann JM, Morel F, Langouët S, Perrin M, Guillygomarc'h A, et al. Effects of phlebotomy therapy on cytochrome P450 2e1 activity and oxidative stress markers in dysmetabolic iron overload syndrome: a randomized trial. Aliment Pharmacol Ther. 2006;24(8):1207-13. PubMed PMID: 17014579
  28. Gautier A, Lainé F, Massart C, Sandret L, Piguel X, Brissot P, et al. Liver iron overload is associated with elevated SHBG concentration and moderate hypogonadotrophic hypogonadism in dysmetabolic men without genetic haemochromatosis. Eur J Endocrinol. 2011;165(2):339-43. PubMed PMID: 21646287
  29. Murali AR, Gupta A, Brown K. Systematic review and meta-analysis to determine the impact of iron depletion in dysmetabolic iron overload syndrome and non-alcoholic fatty liver disease. Hepatol Res. 2018;48(3):E30-E41. PubMed PMID: 28593739
  30. Jaruvongvanich V, Riangwiwat T, Sanguankeo A, Upala S. Outcome of phlebotomy for treating nonalcoholic fatty liver disease: A systematic review and meta-analysis. Saudi J Gastroenterol. 2016;22(6):407-414. PubMed PMID: 27976635
  31. Bardou-Jacquet E, Lainé F, Morcet J, Perrin M, Guyader D, Deugnier Y. Long-term course after initial iron removal of iron excess in patients with dysmetabolic iron overload syndrome. Eur J Gastroenterol Hepatol. 2014;26(4):418-21. PubMed PMID: 24557330
  32. Lobbes H, Gladine C, Mazur A, Pereira B, Dualé C, Cardot JM, et al. Effect of procyanidin on dietary iron absorption in hereditary hemochromatosis and in dysmetabolic iron overload syndrome: A crossover double-blind randomized controlled trial. Clin Nutr. 2020;39(1):97-103. PubMed PMID: 30792142
  33. Lobbes H, Dalle C, Pereira B, Ruivard M, Mazur A, Gladine C. Eicosanoids and Oxylipin Signature in Hereditary Hemochromatosis Patients Are Similar to Dysmetabolic Iron Overload Syndrome Patients but Are Impacted by Dietary Iron Absorption. Ann Nutr Metab. 2024;80(3):117-127. PubMed PMID: 38354712
  34. Hanna HWZ, Baz HN, Al-Kzayer LFY, El Haddad HE, El-Mougy F. Assessment of plasma catecholamines in patients with dysmetabolic iron overload syndrome. J Appl Biomed. 2022;20(4):141-145. PubMed PMID: 36708719
  35. de Jesus RN, Callejas GH, David Mendonça Chaim F, Antonio Gestic M, Pimentel Utrini M, Callejas-Neto F, et al. Roux-en-Y Gastric Bypass as a Treatment for Hepatic Iron Overload: An Exploratory Study. Obes Surg. 2022;32(7):2438-2444. PubMed PMID: 35543890
  36. Castiella A, Arteaga A, Garaizabal I, Sánchez-Iturri MJ, Urreta I, Zapata E. Study of the prevalence of hereditary hemochromatosis (HFE) and secondary causes of hyperferritinemia in patients treated in a bloodletting programme. Clin Res Hepatol Gastroenterol. 2026;50(10):102962. PubMed PMID: 42962819
  37. Liu WY, Lian LY, Zhang H, Chen SD, Jin XZ, Zhang N, et al. A Population-Based and Clinical Cohort Validation of the Novel Consensus Definition of Metabolic Hyperferritinemia. J Clin Endocrinol Metab. 2024;109(6):1540-1549. PubMed PMID: 38124275
  38. Rametta R, Fracanzani AL, Fargion S, Dongiovanni P. Dysmetabolic Hyperferritinemia and Dysmetabolic Iron Overload Syndrome (DIOS): Two Related Conditions or Different Entities? Curr Pharm Des. 2020;26(10):1025-1035. PubMed PMID: 32003680

PubMed Topic Searches

  1. PubMed: dysmetabolic iron overload syndrome
  2. PubMed: metabolic hyperferritinemia
  3. PubMed: phlebotomy in fatty liver disease, randomized trials
  4. PubMed: hepcidin and the metabolic syndrome
  5. PubMed: hyperferritinemia and liver iron on magnetic resonance imaging
  6. PubMed: serum ferritin and alcohol intake

Back to Table of Contents

Connections

Back to Table of Contents