Olive oil, known for its health benefits as a superior alternative to seed oils, has also shown promise in protecting against cognitive decline and associated mortality, according to a 28-year study involving approximately 92,000 individuals.

"Higher olive oil intake was associated with a lower risk of dementia-related mortality, irrespective of diet quality," according to a Harvard T.H. Chan School of Public Health team, whose findings were published in an American Medical Association (AMA) journal.

Participants were asked every four years about their olive oil intake and their general diet, while death records were used where applicable to check for causation, including dementia.

Those who rarely or never used olive oil were more likely to develop conditions such as Alzheimer’s disease, according to the researchers, who said the results of their long-running study "suggest that olive oil intake represents a potential strategy to reduce dementia mortality risk."

"Substituting olive oil intake for margarine and mayonnaise was associated with lower risk of dementia mortality and may be a potential strategy to improve longevity free of dementia," the team concluded.

Higher in antioxidants and lightly processed, the oil from pressed olives is closer to nature than vegetable or seed counterparts, which usually see nutrients and taste diminished by processing and blending.

The team said they did not find anything to link vegetable oils or butter and other dairy goods with cognitive decline.

The findings suggested that regular consumers of olive oil were less likely to develop diabetes than those who were more inclined to use vegetable or seed oils and that it was "plausible" that cooking with olive oil "could be indicative of a healthier diet."

Olive oil prices have soared in recent years, putting it potentially out of reach for many hard-pressed lower-income shoppers, who have faced food, fuel, heating and transport inflation since mid-2021.

In January, according to the European Union's statistics agency, the price of olive oil in the bloc was 50% higher than in 2023.