Related Experiment Video
Updated: Jul 22, 2026
07:12
A Colorimetric Method for Measuring Iron Content in Plants
Published on: September 7, 2018
Summary
Tea consumption significantly inhibits iron absorption from various foods and supplements by forming insoluble iron tannate complexes. This effect can contribute to iron deficiency, especially in diets rich in plant-based foods.
Area of Science:
- Nutritional Science
- Human Physiology
- Food Chemistry
Background:
- Iron deficiency is a prevalent global health issue.
- Dietary factors significantly influence iron absorption.
- Tea is a common beverage worldwide, containing tannins.
Purpose of the Study:
- To investigate the impact of tea consumption on iron absorption in humans.
- To determine the mechanisms behind tea's effect on iron bioavailability.
- To assess the role of ascorbic acid in modulating tea's inhibitory effect.
Main Methods:
- Human volunteer study.
- Assessing iron absorption from various sources (FeCl3, FeSO4, bread, rice meal, haemoglobin).
- Evaluating the effect of tea with and without ascorbic acid, and with cooked vs. uncooked haemoglobin.
Main Results:
- Tea inhibited iron absorption from non-haem iron sources (FeCl3, FeSO4, bread, rice meal) regardless of ascorbic acid presence.
- Tea did not inhibit iron absorption from cooked haemoglobin.
- Inhibition was attributed to the formation of insoluble iron tannate complexes.
Conclusions:
- Tea consumption, due to its tannin content, can significantly reduce non-haem iron absorption.
- The formation of iron tannate complexes is the primary mechanism of inhibition.
- Consuming tea with meals may exacerbate iron deficiency risk in populations with predominantly plant-based diets.
Related Concept Videos
01:28The Early Endosome: Endocytosis of Transferrin
Essential proteins such as insulin or low-density lipoprotein (LDL) and micronutrients such as iron enter a eukaryotic cell through receptor-mediated endocytosis. Subsequently, the early endosomes fuse with the vesicles containing such receptor-ligand complexes and play a vital role in sorting the incoming ligands and receptors. While the ligands are either degraded inside the vesicle or released into the cytosol, their receptors are returned to the plasma membrane for further rounds of...
01:19Drug Absorption: Factors Affecting GI Absorption
The process of oral drug absorption can be influenced by several factors. Weakly acidic drugs tend to be absorbed more readily from the stomach due to their nonionized state. However, absorption may be less efficient in the upper intestine, where drugs are often ionized. Interestingly, despite the stomach's apparent advantage for drug absorption, its mucous layer can hinder diffusion. Its surface area is also smaller than the intestine's, which can further slow down the absorption rate.
In...
In...
01:18Effects of EDTA on End-Point Detection Methods
Different methods, such as visual observance of metal-ion indicators, spectroscopic techniques, and potentiometric methods, can determine the endpoint of an EDTA titration.
In the visual method, metal-ion indicators (metallochromic dyes), which have distinct colors in their free and complex forms, are added to the mixture to signal the titration's end point. They form stable complexes with metal ions, but these complexes are weaker than the corresponding metal–EDTA complexes. As a result, EDTA...
In the visual method, metal-ion indicators (metallochromic dyes), which have distinct colors in their free and complex forms, are added to the mixture to signal the titration's end point. They form stable complexes with metal ions, but these complexes are weaker than the corresponding metal–EDTA complexes. As a result, EDTA...
01:27Mineral, Vitamin and Water Absorption
Electrolytes are essential minerals and ions primarily obtained from the diet and absorbed through the gastrointestinal tract. Most electrolytes are absorbed in the small intestine. While the absorption of iron and calcium primarily occurs in the duodenum, calcium is also absorbed in the jejunum and ileum. In these regions, passive diffusion contributes to its absorption alongside active transport mechanisms in the duodenum. These ions can exit the enterocytes through specialized active...
01:25Factors Influencing Drug Absorption: Disease States and Pharmacology
Multiple disease states can significantly influence the oral drug absorption process by affecting blood flow and the functionality of the gastrointestinal (GI) system. Various GI diseases, including conditions that alter GI motility, such as diarrhea, decreased acid secretions (achlorhydria), and infections, have been associated with reduced drug absorption.
Substances such as alcohol and specific drugs, including antineoplastics, can also negatively impact drug absorption. For instance,...
Substances such as alcohol and specific drugs, including antineoplastics, can also negatively impact drug absorption. For instance,...
01:22Bioavailability: Influencing Factors
Bioavailability refers to the extent and rate at which a drug reaches systemic circulation in its active form. Extent refers to the amount of the drug that makes it into circulation, while rate is the speed at which it enters circulation. It is influenced by several factors critical for optimizing drug formulations, dosing regimens, and therapeutic outcomes.Physicochemical properties of drugs and formulationsThe solubility, stability, and dissolution rate of a drug significantly impact its...