Opting for olive oil may reduce the risk of fatal dementia

A new study suggests that incorporating olive oil into your diet could help reduce the risk of dying from dementia. As many countries face rising rates of Alzheimer's disease and other forms of dementia, the study offers hope that healthy lifestyle factors such as diet can help to prevent or slow the progression of these devastating conditions.

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. 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."

Anne-Julie Tessier, RD, PhD, postdoctoral fellow, Harvard T.H. Chan School of Public Health

Tessier will present the findings at NUTRITION 2023, the flagship annual meeting of the American Society for Nutrition held July 22–25 in Boston.

Dementia includes a range of conditions in which impairments in thinking or memory affect a person's daily activities. Alzheimer's, a progressive and fatal disease affecting an estimated 5.7 million Americans, is the most common form of dementia.

The study is the first to investigate the relationship between diet and dementia-related death. Scientists analyzed dietary questionnaires and death records collected from more than 90,000 Americans over three decades, during which 4,749 study participants died from dementia.

The results indicated that people who consumed more than half a tablespoon of olive oil per day had a 28% lower risk of dying from dementia compared with those who never or rarely consumed olive oil. In addition, replacing just one teaspoon of margarine and mayonnaise with the equivalent amount of olive oil per day was associated with an 8-14% lower risk of dying from dementia.

Research suggests that people who regularly use olive oil instead of processed or animal fats tend to have healthier diets overall. However, Tessier noted that the relationship between olive oil and dementia mortality risk in this study was independent of overall diet quality. This 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."

Previous studies have linked higher olive oil intake with a lower risk of heart disease. Incorporating olive oil as part of a Mediterranean dietary pattern has also been shown to help protect against cognitive decline.

Tessier cautioned that the research is observational and does not prove that olive oil is the cause of the reduced risk of fatal dementia. Additional studies such as randomized controlled trials would be needed to confirm the effects and determine the optimal quantity of olive oil to consume in order to reap these benefits. Overall, however, the study aligns with dietary recommendations and bolsters the evidence that using olive oil in place of margarine or mayonnaise can help to support a healthy diet.