In the first study of its kind, scientists found olive oil could reduce the risk of dying from dementia by 28 per cent.
Olive oil has long been held up as an example of a "super food" that can help you to live longer when consumed as part of a healthy diet. Now a new study suggests that olive oil could help to reduce the risk of dying from dementia.
The study, conducted by researchers at Harvard University in the United States, comes at a time when many countries are facing rising rates of Alzheimer’s disease and other forms of dementia, amid ageing populations.
According to the researchers, using olive oil instead of fats such as margarine and commercial mayonnaise could reduce the risk of dying from dementia.
Dementia includes a range of conditions that affect memory and other mental abilities enough to interfere with daily life. The conditions are caused by physical changes in the brain, with Alzheimer's disease being the most common type.
In the first study to investigate the relationship between diet and dementia-related death, scientists analysed the dietary questionnaires and death records of more than 90,000 US citizens over three decades. Of these, 4,749 were recorded as dying from dementia.
They found that those who consumed more than half a tablespoon of olive oil each day had a 28 per cent lower risk of dying from dementia compared with those who never or rarely ate olive oil.
The study showed how replacing a single teaspoon of margarine or mayonnaise with olive oil each day was also associated with a lower risk of dying from dementia of between 8-14 per cent.
“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, as well,” said Anne-Julie Tessier, a postdoctoral fellow at the Harvard TH Chan School of Public Health.
"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".
Olive oil uniquely beneficial for brain health?
Previous research has suggested that people who use olive oil instead of processed or animal fats tend to have healthier diets, and potentially better health outcomes. Some studies have linked higher olive oil intake with a lower risk of heart disease.
For this study, Tessier noted that the relationship between olive oil and dementia mortality risk in this study was independent of overall diet quality - which may suggest that olive oil has properties that are uniquely beneficial for brain health.
"Some antioxidant compounds in olive oil can cross the blood-brain barrier, potentially having a direct effect on the brain," said Tessier.
"It is also possible that olive oil has an indirect effect on brain health by benefiting cardiovascular health".
However, the research at this stage is observational, and Tessier cautioned that it does not yet prove that olive oil is the cause of reduced risk of fatal dementia.
Further studies will be needed to confirm the effect, but the researchers said the study bolsters the evidence that using olive oil in place of other fats can help to support a healthy diet.