A Challenge to a Dubious Claim
"Canola oil is appealing because it is less expensive than other vegetable oils, and it is advertised as being healthy," says researcher Domenico Praticò who directs the Alzheimer's Center at the Lewis Katz School of Medicine at Temple University. "Very few studies, however, have examined that claim, especially in terms of the brain." Now, previously, in lab research on animals who are prone to brain problems, the Temple researchers have studied how extra-virgin olive oil influences the formation of what are called amyloid plaques and phosphorylated tau. These are destructive proteins in the brain that hamper the function of neurons and can contribute to the frightening disappearance of memory during Alzheimer's disease. In those studies, they found that olive oil shrinks the amount of both amyloid plaques and phosphorylated tau and improves memory.1 But the results with canola oil are quite different. The first obvious change in the lab animals consuming canola oil for six months was significantly more weight gain than the other animals experienced. The second development: their learning abilities and working memories were sharply reduced.2Good Amyloid, Bad Amyloid
Their brains do not improve - they get worse. They have lower amounts of "protective amyloid beta" - a more soluble form of amyloid beta that defends the brain from the destructive insoluble form, amyloid beta 1-42. According to the Temple scientists, the canola diet allows more neurons to be swallowed up by the plaque-forming amyloid beta 1-42. This mucks up neuronal synapses - the contacts between neurons that lets them communicate with each other. The communication breakdown erases memory. "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," says Praticò. "In our model, this change in ratio resulted in considerable neuronal damage, decreased neural contacts, and memory impairment." The idea that there are different types of amyloid beta proteins, with different functions, is an interesting sidelight of this article. Other cutting-edge researchers in dementia, such as Dr. Dale Bredesen of the Buck Institute, hold that the amyloid proteins are a protective reaction to toxins and inflammation - not themselves the cause of Alzheimer's. This Temple University research seems to confirm that view.More Types of Damage Likely to be Discovered
The Temple researchers also suspect that canola oil's possible harm to the brain isn't just restricted to Alzheimer's developments. "There is a chance that the consumption of canola oil could also affect the onset and course of other neurodegenerative diseases or other forms of dementia," warns Praticò. My advice is to stick with olive oil and coconut oil when you cook. Avoid processed foods that list canola oil on the label. Your brain - and other organs - will thank you by functioning better. Olive oil is not particularly good at high temperatures - for instance, frying - because it has a lower smoke point, the point at which a cooking oil forms toxic compounds. Coconut oil is best for high-temperature cooking.