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 as per BBC news service.
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.
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.
