A study has linked 7g of olive oil a day to a huge reduction in dementia-related death, highlighting its benefit to not only heart health, but also brain health.

Researchers from Harvard University found that people who consumed just over half a tablespoon daily have a 28 per cent lower risk of dementia-related death than those who never or rarely consumed it.

Anne-Julie Tessier, a postdoctoral fellow at the Harvard TH Chan School of Public Health and the study’s lead author, said that opting for olive oil instead of margarine and mayonnaise may reduce the chances of dying from dementia.

“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support heart health but potentially brain health,” she said last year when the results of the study were released, but not peer reviewed.

“Some antioxidant compounds in olive oil can cross the blood-brain barrier, potentially having a direct effect on the brain.”

Peer review is the process in which a researcher can have their draft paper assessed by other academics before it is submitted to be published in a scientific journal.

The study

The study examined the self-reported results of 60,000 women and 32,000 men from 1990 to 2018.

From 1990, participants of a decades-old health survey run by nurses measured their dietary intake every four years.

By measuring the results until 2018, and excluding participants with cardiovascular disease or cancer from the baseline, the study found that for “adults, particularly women, consuming more olive oil was associated with lower risk of dementia-related mortality, regardless of diet quality”.

“This association remained significant after adjustment for diet quality scores including adherence to the Mediterranean diet,” the study said.

“Olive oil consumption may lower dementia mortality by improving vascular health.”

In their conclusion, the authors wrote that “the findings extend the current dietary recommendations of choosing olive oil and other vegetable oils to the context of cognitive health and related mortality”.

Health benefits and risks

Several clinical trials have also found similar results, while the Harvard study found the association was significant in both sexes.

The health benefits include reduced risk of heart disease and strokes, anti-inflammatory properties and fats that aren’t saturated.

Olives are either pressed or crushed and separated to extract the oil.

Olives originated from the area around modern-day Iran, Iraq and Syria about 6000 years ago. Photo: Getty

Olive oil has been extracted and used in many cultures, with the earliest known oils being created about 4000BC.

Extra virgin is generally considered the most healthy type of olive oil, above both refined or virgin.

Its anti-inflammatory properties come from a high amount of antioxidants, and olive oils also contain healthy fats that help the heart.

Extra virgin olive oils are generally high in calories and some people may have allergies.