Concentrations of iron similar to those delivered in standard
treatments can trigger DNA damage within 10 minutes, when given to
cells in the lab.
This is the finding of scientists from Imperial College London,
who suggest that researchers need to look carefully at the amount
of iron given in standard treatments, such as tablets and
infusions, and the effects this could be having on the body.
Iron is essential for the body to function and has a crucial
role in transporting oxygen - low levels cause anaemia which leads
to tiredness and lethargy. Iron tablets, which are available over
the counter or on prescription, are taken by millions of people in
the UK - with six million prescriptions issued each year for iron
tablets in England and Wales alone.
In the study the team used human endothelial cells, which line
blood vessels, and added a placebo or an iron solution of 10
micromolar (a similar concentration to that seen in the blood after
taking an iron tablet).
Through looking at genes used within cells, and then examining
the cells in more detail, they found that within ten minutes, cells
treated with the iron solution had activated DNA repair systems.
These were still activated six hours later.
Dr Claire Shovlin of the National Heart and Lung Institute at
Imperial said: "We already knew that iron could be damaging to
cells in very high doses. However, in this study we found that when
we applied the kinds of levels of iron you would find in the blood
stream after taking an iron tablet, this also seemed to be able to
trigger cell damage - at least in the laboratory. In other words,
cells seem more sensitive to iron than we previously thought."
Dr Shovlin added: "This is very early stage research, and we
need more work to confirm these findings and investigate what
effects this may have on the body. We are still not sure how these
laboratory findings translate to blood vessels in the body."
She stressed that prescribed iron supplements are essential for
many patients: "We're not at the stage yet where we would advise
doctors to change their approach to prescribing iron supplements.
Many people need extra iron - it is crucial to allow our bodies to
function properly - and anyone with any concerns about their iron
supplements should talk to their healthcare provider.
"However, this study helps to open the conversation about how
much iron people take. At the moment, each standard iron tablet
contains almost 10 times the amount of iron men are recommended to
eat each day - and these dosages haven't changed for more than 50
years. This research suggests we may need to think more
carefully about how much iron we give to people, and try and tailor
the dose to the patient."
The team initially started researching this area after finding
that a small proportion of people using iron tablets for the
condition hereditary haemorrhagic telangiectasia, which causes
abnormalities in the blood vessels, reported their nose bleeds got
worse after iron treatment.
The paper, Low dose iron treatments induce a DNA damage response in human
endothelial cells within minutes, is published in PLOS
ONE.