The long-term consumption of canola oil might be bad for the brain, new research suggests.
A US study involving mice has linked the consumption of the vegetable cooking oil with the symptoms of Alzheimer's disease, including worsened memory, worsened learning ability and weight gain.
The Philadephia-based University of Temple researchers started by dividing the mice into two groups at six months of age, before the animals developed signs of Alzheimer's.
One group was fed a normal diet while the others were fed a diet supplemented with the equivalent of about two tablespoons of canola oil a day.
When the mice were assessed 12 months of age, one of the first differences observed was body weight. Animals on the canola oil-enriched diet weighed significantly more than mice on the regular diet.
Maze tests to assess working memory, short-term memory and learning ability uncovered more differences.
Most significantly, the mice that consumed canola oil over the six months suffered impairments in working memory.
Examination of brain tissue from the two groups of mice revealed the canola oil consuming animals had greatly reduced levels of amyloid beta 1-40, which acts as a buffer from the harmful amyloid beta 1-42. Amyloid beta 1-42 is crucially involved in Alzheimer's disease.
"Based on the evidence from this study, canola oil should not be thought of as being equivalent to oils with proven health benefits," the authors said in an article published in the journal Scientific Reports.
While more research was needed the researchers also said there "is a chance" the consumption of canola oil could affect the onset of neurodegenerative diseases or other forms of dementia.