Research has revealed that canola oil consumption is associated with weight gain, reduced learning ability and reduced memory. The researchers had previously made use of an Alzheimer’s disease mouse model to determine the health benefits of olive oil. They discovered that Alzheimer mice consuming an extra-virgin olive oil enriched diet experienced memory improvement and had reduced amyloid plaque and phosphorylated tau levels. For this current study, they wanted to see if canola oil had the same benefits for the brain.
The researchers wanted to see how brain function is affected by canola oil consumption, so the study was focused on the impairment of memory and the formation of neurofibrillary tangles and amyloid plaques in the Alzheimer’s mouse model. Phosphorylated tau and amyloid plaques, responsible for tau neurofibrillary tangle formation, contribute to neuronal degeneration and dysfunction and Alzheimer’s memory loss. The mouse model was developed to reproduce the progress of human Alzheimer’s from an early asymptomatic phase to the late full-blown disease.
At 6 months old, the mice were split up into 2 groups before developing signs of Alzheimer’s. One of the groups consumed a normal diet, and the other group consumed a canola oil supplemented diet which amounted to approximately 2 tbsp of canola oil a day. They were then examined when they were 12 months old. Body weight was one of the differences seen between the 2 groups, the canola oil-enriched diet mice weighed considerably more compared to those on the regular diet. Additional differences were uncovered with maze tests for assessing learning ability, short-term memory and working memory. The most significant finding was that mice consuming canola oil for six months had working memory impairments.
Brain tissue examinations from both groups showed that mice consuming the canola oil supplemented diet had hugely reduced amyloid beta 1-40 levels, which is the more soluble kind of the amyloid beta proteins. Amyloid beta 1-40 is generally believed to play a beneficial part in the brain, acting as a buffer for amyloid beta 1-42, the insoluble and harmful kind. Because of reduced amyloid beta 1-40, the mice on the canola oil enriched diet also experienced an increase in amyloid plaque formation, with neurons surrounded by amyloid beta 1-42. A considerable reduction in the amount of contacts between neurons was also observed, indicating extensive injury of synapses, the areas where neurons make contact with each other, and which play an important part in memory retrieval and formation. The study results therefore suggest that canola oil consumption is detrimental to brain health.