The study, published in Neurology, reports that higher dietary intakes of olive oil may reduce the risk of developing stroke by over 40 per cent. The researchers also reported that those with the highest levels of plasma oleic acid – a monounsaturated omega-9 fatty acid found at high levels in olive oil – had a 73 per cent reduction in the risk of stroke.
“Our research suggests that a new set of dietary recommendations should be issued to prevent stroke in people 65 and older,” said the study author Dr Cécilia Samieri, of University of Bordeaux and the National Institute of Health and Medical Research (INSERM) in Bordeaux, France.
“Stroke is so common in older people and olive oil would be an inexpensive and easy way to help prevent it,” she added.
The researchers followed 7,625 people with no history of stroke, aged 65 and older from three cities in France: Bordeaux, Dijon and Montpellier.
The participants were categorized by olive oil consumption into one of three groups: ‘no use’, ‘moderate use’ such as using olive oil in cooking or as dressing or with bread, and ‘intensive use’, which included using olive oil for both cooking and as dressing or with bread.
After adjusting their findings to account for diet, physical activity, body mass index and other risk factors for stroke, the researchers reported that people who regularly used olive oil for both cooking and as dressing had a 41 percent lower risk of stroke compared to those who never used olive oil in their diet.
The authors also measured blood plasma oleic acid, finding that high levels were associated with lower stroke incidence.
“Compared to those in the first tertile [with lowest levels], participants in the third tertile [highest levels] of plasma oleic acid had a 73 per cent reduction of stroke risk,” said the authors.
Olive oil has been associated with potentially protective effects against many cardiovascular risk factors. Rich in phenolic compounds, such as oleuropein and cafeic acid, the oil has attracted attention because of their potential anti-diabetic, anti-atherosclerotic and anti-inflammatory properties. Such compounds have been also associated with the antioxidant activity of olive oil.
Commenting on the study Dr Sharlin Ahmed of the Stroke Association, said: “Olive oil has long been known to have potential health benefits.
“It's promising to see that it could have a similar protective function against stroke … However, it's important to note that a person's risk of stroke would only be reduced through consuming olive oil as an alternative to other cooking fats and as part of a healthy balanced diet that is low in saturated fat and salt.
In an accompanying editorial, Dr Nikolaos Scarmeas from Columbia University noted that it is not clear which particular elements of olive oil could be protective, while the effects of olive oil could even be indirect by making other healthy foods tastier.
“Olive oil is usually added to other foods (i.e., fruits and vegetables, legumes, cereals, and fish) and may contribute indirect benefits by increasing the palatability and consumption of foods that may have health-promoting potential,” he said.
Published online before print, doi: 10.1212/WNL.0b013e318220abeb
“Olive oil consumption, plasma oleic acid, and stroke incidence”
Authors: C. Samieri, C. Féart, C. Proust-Lima, E. Peuchant, C. Tzourio, et al