That’s the idea behind a supplement created by Swiss scientists, who say it could provide an alternative approach to managing iron-loading diseases such as hereditary haemochromatosis, for which current treatments are highly invasive.
The supplement, which contains black tea, cocoa powder, and grape juice, was shown in clinical trials to decrease iron absorption by as much as 40%, according to Michael Zimmermann, professor emeritus at the department of health sciences and technology at ETH Zürich.
“Not only might this supplement of polyphenols given to haemochromatosis patients be beneficial in terms of reducing iron absorption accumulation, but it might also have beneficial systemic health benefits,” he told an audience at last week’s 16th World Congress on Polyphenols Applications 2023.
Iron-loading diseases affect millions worldwide
Iron-loading diseases like hereditary haemochromatosis and iron-loading thalassaemia affect millions of people worldwide and are major causes of disability.
Haemochromatosis, an iron storage disorder that results in excess absorption of dietary iron, is one of the most common genetic diseases in Caucasian populations, mainly in people of Northern European origin.
It is caused by a range of genetic mutations, all of which disrupt the production of hepcidin – the major regulator of iron metabolism in the body – by the liver. When there is too little hepcidin circulating in the body, there is uncontrolled excess dietary iron absorption, Zimmermann explained.
“Iron is one of these rare trace elements where we don't have any way of actively excreting [it] from the body,” he said. “So we carefully control our body iron levels simply by regulating absorption. And when hepcidin can't limit absorption, then we get accumulation of iron.”
Iron accumulation in the body results in widespread disease: high levels in the liver lead to cirrhosis, high pancreatic iron results in diabetes, and in people with uncontrolled haemochromatosis, so much iron accumulates in the body that their skin becomes bronze.
Polyphenol supplements: An alternative to invasive treatments?
Currently, the medical management of haemochromatosis patients consists of phlebotomy – drawing blood to remove the extra iron. When patients are first diagnosed, this is required weekly or bi-weekly; depending on how severe their disorder is, they might need serial phlebotomy every two to four months for the rest of their lives.
There is “very little evidence” to support dietary modifications in haemochromatosis, Zimmermann said. The haemochromatosis diet focuses on limiting intakes of heme iron from meat, as well as limiting intakes of foods rich in vitamin C in meals containing non-heme iron, as the nutrient is an enhancer of non-heme iron absorption. But vegetarian patients, for example, don't have lower iron stores.
However, haemochromatosis patients are advised to increase intakes of coffee and tea because of their rich polyphenol content, with the aim of inhibiting iron absorption from foods and supplements.
Zimmermann gave an example of a study that his team carried out in Zurich which showed that in participants receiving high-dose iron supplements (100 mg), consuming just one cup of instant coffee reduced iron absorption by as much as 50%.
This gave them the idea for a polyphenol supplement, to be taken with meals, specifically formulated to be very potent iron binder. They hypothesised that this might reduce iron absorption from diets and allow haemochromatosis patients to avoid tissue damage from excess iron; they hoped it would also limit the number of phlebotomy sessions required.
Polyphenol supplements reduce iron absorption by 40%
The researchers performed in vitro iron digestion experiments to determine iron precipitation from 12 polyphenol-rich dietary sources, and formulated a supplement containing black tea powder, cocoa powder, and grape juice extract.
A multi-centre, single-blind, placebo-controlled crossover study was carried out in collaboration with Portuguese colleagues to assess the effect of the supplement on iron absorption among hereditary haemochromatosis patients via a test meal and drink.
“The polyphenol supplements actually reduced iron absorption for the meal by 40% and from the drink by about 40%,” Zimmermann said.
Although he conceded it was a “very small study”, his team is soon due to publish findings from their research in iron-loading thalassaemia patients in Thailand, for which the preliminary results look “very similar”.
“This might be a supplement which would not only be useful for hemochromatosis patients, but also for the hundreds of millions of patients in South-East Asia who are affected by iron-loading thalassaemia,” he said.