Letter: Iron in the brain

From Michael John Harris

I know nothing about ink or paper, but found Nicola Jones’s article illuminating from a related if rather different perspective (14 September, p 38).

Researchers now think that oxygen free radicals generated by metals are important in many biological systems, and are frequently involved in degenerative processes, possibly causing such conditions as Alzheimer’s and Parkinson’s disease (26 August 2000, p 36).

The photographs of paper destroyed by ink that accompany your article are of enormous symbolic significance to anybody who knows they are suffering from a degenerative disease caused by free radical reactions, induced by iron or other wayward metals. And although the mechanisms may not be totally analogous, it does beg the question that if iron is doing this to paper, what is it doing over a lifetime to your body?

There could be a connection with Parkinson’s disease. This is a degenerative disease that tends to afflict areas of the brain that are pigmented. The main symptoms of the disease are thus associated with decline of part of the brain called the substantia nigra, which gets its name from its black pigmentation.

The pigmentation is caused by a substance called neuromelanin, which accumulates with age and declines in Parkinson’s disease. The pigment accumulates iron and shields neurons from the metal. The cause of Parkinson’s disease is controversial, but one hypothesis is that it is associated with the release of iron from neuromelanin and other sources and, following this, iron-induced free radical attack.

Peterborough, Cambridgeshire