Cited by 490Phytochemicals and Antioxidant ActivitiesIron Metabolism and DisordersCoffee research and impacts

The DOI matches its Crossref record; 61 of the 61 references it cites were found in a registry or an index; 6 of the 21 sources its claims cite were checked for support.

Inhibition of non-haem iron absorption in man by polyphenolic-containing beverages

Open access
Hurrell, Richard F., Reddy, Manju, Cook, James D.·1999·British Journal of Nutrition

Abstract

The effects of different polyphenol-containing beverages on Fe absorption from a bread meal were estimated in adult human subjects from the erythrocyte incorporation of radio-Fe. The test beverages contained different polyphenol structures and were rich in either phenolic acids (chlorogenic acid in coffee), monomeric flavonoids (herb teas, camomile ( Matricaria recutita L.)), vervain ( Verbena officinalis L.), lime flower ( Tilia cordata Mill.), pennyroyal ( Mentha pulegium L.) and peppermint ( Mentha piperita L.), or complex polyphenol polymerization products (black tea and cocoa). All beverages were potent inhibitors of Fe absorption and reduced absorption in a dose-dependent fashion depending on the content of total polyphenols. Compared with a water control meal, beverages containing 20–50 mg total polyphenols/serving reduced Fe absorption from the bread meal by 50–70 %, whereas beverages containing 100–400 mg total polyphenols/serving reduced Fe absorption by 60–90 %. Inhibition by black tea was 79–94 %, peppermint tea 84 %, pennyroyal 73 %, cocoa 71 %, vervain 59 %, lime flower 52 % and camomile 47 %. At an identical concentration of total polyphenols, black tea was more inhibitory than cocoa, and more inhibitory than herb teas camomile, vervain, lime flower and pennyroyal, but was of equal inhibition to peppermint tea. Adding milk to coffee and tea had little or no influence on their inhibitory nature. Our findings demonstrate that herb teas, as well as black tea, coffee and cocoa can be potent inhibitors of Fe absorption. This property should be considered when giving dietary advice in relation to Fe nutrition.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

In adult volunteers, polyphenol-containing beverages—black tea, herb teas, coffee and cocoa—strongly inhibited non-haem iron absorption from a bread meal in a dose-dependent manner. Black tea was generally most inhibitory, and adding milk had little or no effect.

Key findings

  • All test beverages inhibited Fe absorption dose-dependently: beverages with 20–50 mg total polyphenols/serving reduced absorption by 50–70%, while those with 100–400 mg/serving reduced absorption by 60–90%.
  • Compared with water control meals, absorption ratios were black tea 0.06–0.21, peppermint 0.16, pennyroyal 0.27, cocoa 0.29, vervain 0.41, lime flower 0.48 and camomile 0.53; corresponding inhibition was black tea 79–94%, peppermint 84%, pennyroyal 73%, cocoa 71%, vervain 59%, lime flower 52% and camomile 47%.
  • At identical total polyphenol concentrations, black tea was more inhibitory than cocoa and the herb teas camomile, vervain, lime flower and pennyroyal, but equal to peppermint tea. Even 5% black tea, containing only 20 mg polyphenol/serving, reduced Fe absorption by almost 70% (absorption ratio 0.34).
  • Adding milk had little or no influence: milk slightly increased Fe absorption from tea (0.71% to 0.96%; ratio 1.36, P<0.05) but had no effect on coffee (ratio 1.04, P>0.05). Coffee was less inhibitory than tea (2.81% vs 0.71% in study 6).

Methods

  • Eight separate Fe absorption studies were performed in 77 volunteers (23 males, 54 females, aged 19–40 years), with 8–10 subjects per study; all were healthy and non-anaemic, serum ferritin ranged from 9 to 193 g/l, and five female subjects were Fe-deficient (serum ferritin ≤12 g/l).
  • Fe absorption was measured by the extrinsic tag radio-Fe technique using 55Fe and 59Fe, with test meals of Fe-fortified bread rolls plus beverages or water, and absorption estimated from erythrocyte incorporation at 2 weeks; four measurements were made per subject.
  • Total polyphenols in tea, herb teas and cocoa were measured by the Folin-Ciocalteau method with catechin as standard; coffee was analysed for chlorogenic acid by the AOAC method; Fe was determined by atomic absorption spectroscopy. Statistical analysis used log-transformed absorption values and paired tests.

Limitations

  • The authors state that their studies used a simple bread meal and may not extrapolate directly to more complex meals containing a wider range of Fe absorption inhibitors and enhancers; they also note that different herb tea concentrations contained different polyphenol types, which may explain the less clear polyphenol–absorption relationship for herb teas.
  • The authors state that the important public-health question is whether regular consumption affects Fe status, but their single-meal studies cannot resolve this, and population evidence is mixed.
  • Evident from the text: the findings are short-term absorption measurements rather than clinical iron-status outcomes, each study had only 8–10 subjects, and the wide serum ferritin range with five Fe-deficient women may influence absorption responses.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1017/s0007114599000537

Cites

61 of 61 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Verification

Claims the paper makes

31 Own result · 7 No full text of the sources · 5 Own interpretation · 2 Supported · 2 Supported so far · 2 Partly supported · 2 Not checked yet · 2 Own method · 1 Sources not found · 1 No basis given · accuracy not yet measured

Show all 41 claims

  • It may state two separate claims as one. 9
  • Probably not a substantial claim. 5
14 of 14
  • The paper relies on this without support.

    Polyphenol compounds can complex with Fe in the intestinal lumen, making Fe unavailable for absorption.

    “The phenolic compounds are released from the food or beverage during digestion, and can complex with Fe in the intestinal lumen making it unavailable for absorption.”
1 of 1

Citations

Cites

Show all 60 references

Research works printed but not linked: 1

  1. 1989, Recommended Dietary Allowances

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Metadata

Authors
Hurrell, R. F., Reddy, M., & Cook, J. D.
Affiliations
  • ETH Zurich (CH)
  • Iowa State University (US)
  • University of Kansas Medical Center (US)
Corresponding author
Hurrell, Richard F.
Venue
British Journal of Nutrition
Published
1999-04
Volume
81
Issue
4
Pages
289-295
ISSN
  • 0007-1145 (ISSN-L)
  • 1475-2662
OpenAlex
W2148247285
Cited by
490
References
60
Citations by year
2026: 23 · 2025: 15 · 2024: 17 · 2023: 16 · 2022: 19 · 2021: 23 · 2020: 20 · 2019: 19 · 2018: 18 · 2017: 20 · 2016: 16 · 2015: 22 · 2014: 22 · 2013: 35 · 2012: 21
FWCI
5.29
Type
journal article
Language
en
Open access
Locations
  • British Journal Of Nutrition (publishedVersion)
  • PubMed (publishedVersion)
  • reroDoc Digital Library (submittedVersion)
  • Repository for Publications and Research Data (ETH Zurich) (submittedVersion, other-oa)
  • Iowa State University Digital Repository (Iowa State University) (submittedVersion)
  • ETH Zürich Research Collection
Topics
  • Health Sciences › Medicine › Biochemistry (medical) › Phytochemicals and Antioxidant Activities
  • Health Sciences › Medicine › Hematology › Iron Metabolism and Disorders
  • Health Sciences › Medicine › Pharmacology (medical) › Coffee research and impacts
Keywords
polyphenols, iron absorption inhibition, black tea, Theobroma cacao, coffee, peppermint tea, Mentha pulegium, Verbena officinalis, chamomile, flavonoids, phenolic acids, chlorogenic acid, dietary iron, milk
MeSH terms
Adult, Animals, Beverages, Bread, Coffee, Dose-Response Relationship, Drug, Erythrocytes, Female, Humans, Intestinal Absorption, Iron, Male, Milk, Phenols, Tea

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