Eating a high amount of polyunsaturated fats and vitamin E may halve the risk of developing motor neurone disease, a study suggests.
Polyunsaturated fats include omega 3, in fish and leafy vegetables and omega 6, in cereals and whole-grain bread.
Dutch researchers found people who had the highest daily intake of the fats had a 60% lower risk of developing MND compared to those who ate the least.
The study will appear in the Journal of Neurology Neurosurgery and Psychiatry.
MND, a progressive fatal condition that causes wasting of the muscles, is thought to be caused by genetic and environmental factors, and diet has been previously implicated in its development.
It affects about 5,000 people in the UK and is most common among people aged 50 to 70.
The researchers from the University Medical Center in Utrecht in the Netherlands looked at 132 patients with potential or definite amyotrophic lateral sclerosis (ALS), one of the disabling conditions known as MND.
They completed a questionnaire, detailing their regular dietary intake before they became ill, of polyunsaturated fats, vitamin E, and a range of other nutrients.
The results were compared with those of 220 healthy people.
Factors such as age, sex, energy intake, weight, and smoking were taken into account.
It was found that total energy intake and consumption of dietary supplements were the same in both groups.
But patients with ALS consumed significantly less polyunsaturated fats and vitamin E than the healthy group.
The highest daily intake of fats - more than 32 g a day - was associated with a 60% lower risk of developing ALS compared with the lowest daily intake of less than 25 g.
In addition, a daily vitamin E intake of between 18 and 22 mg was associated with a 60% lower risk of developing ALS compared with the lowest daily intake of less than 18 mg.
The results were true even after taking account of other influential factors.
No strong associations were found for any of the other nutrients.
Writing in the journal, the researchers led by Dr Jan Veldink, said: "This study showed a higher premorbid [pre-illness] dietary intake of polyunsaturated fats and vitamin E was associated with a 50 to 60% decreased risk of developing ALS."
He said the findings were in line with previous research which has shown polyunsaturated fats can reduce the risk of Alzheimer's disease and Parkinson's disease.
Dr Veldink and his team said it was not clear why there were benefits from eating more polyunsaturated fats and vitamin E, but suggested they might prevent the cell damage and death seen as the disease develops - either directly or indirectly.
Belinda Cupid, research manager at the UK's MND Association, said: "This is promising research.
"The identification of any factors that may help reduce the risk of developing MND represents an important step forward."