Olive oil can help prevent strokes in people over 65, a study suggests.
Researchers followed around 7,000 people aged 65 and over living in three French cities, for at least five years.
They found those who used a lot of olive oil in cooking or as a dressing or dip had a lower risk of stroke than those who never used it.
The researchers say older people should be given new dietary advice regarding olive oil, based on the findings, which are published in the journal Neurology.
Lead author, Dr Cecilia Samieri, of the University of Bordeaux, said: "Our research suggests that a new set of dietary recommendations should be issued to prevent stroke in people 65 and older.
"Stroke is so common in older people, and olive oil would be an inexpensive and easy way to help prevent it."
The researchers studied the medical records of 7,625 people aged 65 and older living in Bordeaux, Dijon and Montpelier.
They were asked whether they used olive oil in cooking, on salads or with bread intensively, moderately or never.
Most used extra virgin olive oil, which is common in France.
After around five years, 148 of the men and women had had a stroke.
The study found the stroke risk was 41% lower in those who regularly used olive oil compared with those who abstained, once other factors such as diet, exercise and weight were taken into account.
This works out as a 1.5% risk over six years, compared with 2.6%.
Commenting on the study, published in Neurology, Sharlin Ahmed of the Stroke Association, said: "Olive oil has long been known to have potential health benefits.
"It is believed that it could protect against conditions such as high cholesterol, high blood pressure and heart disease and so 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.
"This is also a study based on responses from the public and not a clinical trial. A lot more research therefore needs to be carried out to scientifically test the effectiveness of olive oil as an ingredient that can protect against stroke."