Two tablespoons of canola oil daily may worsen memory, learning ability as well as cause weight gain in people with Alzheimer's disease, claims a study.
The study, conducted on mice, suggested that the long-term consumption of the vegetable oil which is often promoted as a healthy cooking oil may actually harm the brain.
Mice fed on the canola oil-enriched diet weighed significantly more than mice on the regular diet. Canola oil, or canola for short, is a vegetable oil derived from rapeseed.
Consuming canola oil for over a period of six months also led to impairments in working memory. Additionally, maze tests showed that short-term memory and learning ability also suffered damages.
"Even though canola oil is a vegetable oil, we need to be careful before we say that it is healthy," said Domenico Pratico, Professor at the Temple University in Pennsylvania.
"Based on the evidence from this study, canola oil should not be thought of as being equivalent to oils with proven health benefits," Pratico said, in the paper published in the journal Scientific Reports.
Moreover, brain tissues from the mice on canola diet revealed that these animals had greatly reduced levels of amyloid beta 1-40.
Amyloid beta 1-40 is the more soluble form of the amyloid beta proteins and is generally considered to serve a beneficial role in the brain. It acts as a buffer for the more harmful insoluble form, amyloid beta 1-42.
"Amyloid beta 1-40 neutralizes the actions of amyloid 1-42, which means that a decrease in 1-40, like the one observed in our study, leaves 1-42 unchecked," Pratico explained.
"In our model, this change in ratio resulted in considerable neuronal damage, decreased neural contacts, and memory impairment."
Conversely, Alzheimer mice fed a diet enriched with extra-virgin olive oil had reduced levels of amyloid plaques and phosphorylated tau and experienced memory improvement, the researchers said.