Although health professionals and scientists have been extolling the virtues of a vegan diet in recent years, it still hasn’t managed to replace the Mediterranean diet in terms of health benefits.

Renowned for its variety of foods rich in seasonal produce and low in refined products and red meat, this diet – also known as the “Cretan diet” – is said to be beneficial for balanced intestinal transit, cardiovascular health, and even mental wellbeing.

And now, Harvard researchers are going one step further: in a study presented last July at the annual meeting of the American Society for Nutrition, the conclusions of which were published just this month in the journal Jama Network Open, they suggest that regular consumption of olive oil may be associated with a reduced risk of death from dementia.

This finding was established after analysing a wealth of data, including dietary questionnaires, involving 92,383 adults over 28 years. During this period, over 4,700 participants died of dementia.

In detail, the results revealed that consuming more than half a tablespoon of olive oil per day was associated with a 28% lower risk of dying from dementia.

The researchers also noted that replacing one teaspoon of margarine and mayonnaise with an equivalent amount of olive oil per day is associated with an 8-14% reduction in the risk of dying from dementia, irrespective of the diet followed.

The scientists noted that people who regularly consumed olive oil instead of processed or animal fats tended to have a healthier diet overall.

“Our study reinforces dietary guidelines recommending vegetable oils such as olive oil, and suggests that these recommendations not only support heart health but potentially brain health, too.

“Opting for olive oil, a natural product, instead of fats such as margarine and commercial mayonnaise is a safe choice and may reduce the risk of fatal dementia,” concluded Anne-Julie Tessier from the Harvard TH Chan School of Public Health.

This is only an observational study, meaning there is no evidence to prove that olive oil is the cause of the reduced risk of fatal dementia. This is an important detail, one which researchers say would require additional study.

According to data from the World Health Organization (WHO), more than 55 million people worldwide are living with dementia, with some 10 million new cases every year. Alzheimer’s disease is the most common form of dementia, accounting for 60-70% of cases.