Mediterranean staple may reduce risk of death from dementia, study finds

A daily tablespoon of olive oil could reduce the risk of dying from dementia, according to a new study by Harvard scientists.

For more than 92,000 adults observed over 28 years, consuming at least 7 grams (a little more than half a tablespoon) of olive oil daily was associated with a 28% lower risk of dementia-related death, compared to those who never or they rarely ate olives. oil, the study published Monday in the journal JAMA Network Open found.

The study is the finalized, peer-reviewed version of an abstract—initial research that the authors presented in July 2023 at the American Society for Nutrition annual meeting. To the authors’ knowledge, they were also the first to investigate whether the staple food of the Mediterranean diet is related to the risk of death from this disease.

“Our study reinforces dietary guidelines that recommend vegetable oils such as olive oil and suggests that these recommendations not only support heart health but potentially also brain health,” said study co-author Anne-Julie Tessier, a research associate at nutrition at the TH Chan School of Harvard University. of Public Health, in a press release from last year’s summary. “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.”

At the beginning of the study, research participants had an average age of 56 years. The group included nearly 60,600 women who had participated in the Nurses’ Health Study from 1990 to 2018, and nearly 32,000 men who had been in the Health Professionals Follow-up Study during the same period. The first study investigated risk factors for major chronic diseases among women in North America, while the second investigates the same issues but for men.

The authors of the latest study evaluated participants’ diets every four years using a questionnaire and the Alternative Healthy Eating Index, which assigns scores to foods and nutrients that predict chronic diseases. The higher someone scores on this index, the better.

Replacing 5 grams (about 1.2 teaspoons) of margarine or mayonnaise consumed daily with olive oil was associated with an 8% to 14% lower risk of death from dementia. The authors found that the results of substitution with other vegetable oils or butter were not significant.

Participants with the APOE e4 gene, the strongest known genetic risk factor for Alzheimer’s disease, were five to nine times more likely than non-carriers to die from dementia, but the olive oil findings held up after that the authors took this factor into account.

Duane Mellor, a registered dietitian who was not involved in the study, said in July that the research does not prove a cause-and-effect relationship, but rather an association.

“More research is needed,” Mellor, director of nutrition and evidence-based medicine at Aston Medical School at Aston University in the United Kingdom, said in a news release.

Reduce the risk of dementia

The potential benefits of olive oil for brain health could be due to antioxidant compounds that can cross the blood-brain barrier and directly affect the brain, Tessier said.

“It is also possible that olive oil has an indirect effect on brain health by benefiting cardiovascular health,” he added.

Although the overall quality of the participants’ diet did not make a difference in the findings, those who consume olive oil may have healthier lifestyles overall.

“There are many, many differences between people who consume olive oil and those who don’t, and it is never possible to fully explain all the potential confounding factors,” said David Curtis, honorary professor of genetics, evolution and the environment at University College. . London, he said in a July press release.

Additionally, the way the Mediterranean diet was scored, as part of the diet quality assessment, had “only” nine points and is based on the average intake of the population, Mellor told CNN in an interview in May. .

“It may be more accurate to use a dietary assessment that looks at a broader number of foods, since more than (nine) items make up a healthy diet,” Mellor added.

Another important point to keep in mind is that about half of dementia cases are caused by vascular disease, Curtis added.

“Anything that improves cardiovascular health, such as not smoking, would be expected to reduce the risk of dementia,” he said. “Olive oil consumption has been shown to be associated with better cardiovascular health, so one would expect it to also be associated with a lower risk of dementia.”

Olive oil has been found to be helpful for heart, brain, bone health, and more. In addition to cooking with olive oil, you can also use it to make salad dressings or vinaigrettes, mayonnaise, pesto, or bread sauce. People should also remember that when it comes to food and brain function, it’s not just about what we eat, but how we eat, Mellor said.

“Staying sociable at mealtimes and eating with others can benefit our short-term mental health and cognitive function as we age,” Mellor added.

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