Scientists in Japan have indicated that consuming large amounts of monosodium glutamate (MSG) may damage vision. MSG is popularly used to flavour processed and oriental foods.

Rats fed a diet high in MSG developed thinner retinas and began to go blind. Glutamate is an amino acid that acts as a neurotransmitter, a chemical that transmits signals between nerve cells.

However, optical expert in the UK have responded to the research by saying that people would have to have an exceptionally high intake of MSG before they suffered problems. The occasional Chinese takeaway is not expected to cause problems.

Hiroshi Ohgur, who led the research at Hirosaki University, conceded that the research had used large amounts of MSG, and added: "Lesser amounts should be OK - but the precise borderline amount is still unknown."

The research was published in New Scientist magazine. To read it, click here