Mice with a similar condition who were starved for 48 hours not only had fewer symptoms, but their brains showed fewer signs of the advance of the illness.

This is the latest study to suggest that diet can have an impact on MS.

And the researchers concede that the effect they have noticed may be due to the removal of just one ingredient from the diet - but they do not yet know which one.

MS is a neurological condition in which the body's own immune system attacks the vital coating of nerve fibres in the brain.

We have to remember that the animal model of MS used here doesn't necessarily mean that same effect would be found in humans Spokesman, Multiple Sclerosis Society of Great Britain

This leads to the appearance of "lesions", and disabling attacks.

MS experts generally advise patients to simply eat a healthy, balanced diet wherever possible, although prior studies have suggested that a reduction in dietary fat, and the addition of various supplements may have benefits in reducing the severity or frequency of attacks.

Two day fast

The latest study, published in the Journal of Clinical Investigation, was carried out at the University of Napoli Federico II in Italy.

Mice bred with a neurological condition very similar to MS were deprived of food for 48 hours.

They still went on to develop the disease and have attacks, but they had fewer brain lesions and their physical symptoms were less severe.

Professor Guiseppe Matarese wrote: "Using a nutritional approach together with other drugs might offset the progression of MS."

It is uncertain why starvation might have a positive response on MS, but some scientists believe that a chemical called leptin, released by the body to reduce appetite after a meal, may be somehow involved in the immune response that causes MS.

A spokesman for the Multiple Sclerosis Society of Great Britain told BBC News Online that a healthy balanced diet was the best current advice.

He said: "We have to remember that the animal model of MS used here doesn't necessarily mean that same effect would be found in humans."