Multiple sclerosis could be linked to difficulty in processing iron and aluminium, a study has suggested.
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Scientists at Keele University, Staffordshire, compared levels of the metals in the urine of people with MS and others without the condition.
Significantly higher levels than expected were found in those with MS.
Experts said the research was interesting, but MS was a complex disease and more work was needed before a link could be confirmed.
The study compared 10 MS patients with the relapsing-remitting form of the disease and 10 who had the more advanced secondary progressive form with 20 people who did not have MS.
They looked at iron levels because the metal has been linked with the facilitation and acceleration of oxygenated damage.
It was found that iron levels were significantly higher in people with MS, particularly so in those with the secondary progressive form of the disease.
People with the relapsing-remitting form of the disease were found to have very high levels of aluminium - up to 40 times those seen in the group who did not have MS.
The levels are as high as those seen in people with a condition known as aluminium intolerance.
MS is an autoimmune disease caused by the immune system turning in on itself and attacking the body's own tissues.
In MS, immune cells destroy the myelin sheath that surrounds nerve fibres in the brain and spinal cord and enables them to transmit impulses.
Dr Christopher Exley, a bio-organic chemist at Keele, who ran the study, said: "We know from animal studies that myelin is the preferred target for aluminium.
"As myelin breaks down, something called myelin basic protein is found in urine.
"It could be that aluminium is coming out with that. We are going to do further tests to see if that is the case."
The present understanding is that developing MS is due to a combination of having a genetic susceptibility and environmental factors.
Dr Exley said: "We hypothesise that susceptibility genes may have something to do with how iron is metabolised in the body - something may be going wrong.
"And it may be that aluminium is a previously unrecognised factor that exacerbates that problem, which then manifests itself in some as MS."
Dr Lee Dunster, head of research and information at the MS Society, said, "These are interesting and unexpected findings but MS is a highly complex, multi-factoral disease and further research in a larger study is needed to see how significant they may be."