Study Finds Daily Olive Oil Consumption Linked to Lower Risk of Dementia and Cardiovascular Disease, Harvard University Researchers Say

Is olive oil really good for your health? Or is it just a sign of healthy eating habits? A study recently published in JAMA Network Open has started this debate. An observational study led by researchers at the Harvard TH School of Public Health examined two groups of US health professionals and found that daily consumption of olive oil was associated with a lower risk of death from dementia.

■ Truth

– This study found that people who ate more than half a spoonful of olive oil per day had a 28% lower risk of death from dementia compared to people who ate very little olive oil.

– Participants who consumed more olive oil had a lower risk of death from dementia, regardless of diet level or whether they adhered to a Mediterranean diet (including fruit fresh, vegetables, whole grains, nuts, and moderate amounts of fish and poultry).

– Researchers found that replacing 1 teaspoon of margarine and mayonnaise with an equal amount of olive oil reduced the risk of death from dementia by 8 to 14 percent.

– The study followed two groups of more than 92,000 American male and female medical professionals over 28 years. About 65% of the participants were women, and 4,751 people died of dementia during the study period.

■ Background information

Olive oil consumption is associated with a reduced risk of cardiovascular disease. Olive oil is a major part of the Mediterranean diet. A study published in 2014 found that extra virgin olive oil, in particular, was associated with a lower risk of cardiovascular disease in older adults.

The recently published study found that from 2022 on the same two groups, compared to people who ate very little olive oil, more olive oil was associated with about a 19% lower risk die of cardiovascular disease lost.

Olive oil also “appears to have a beneficial effect on cognitive decline” when used in the Mediterranean diet, said Marta Guasch-Perre, professor of nutrition at the Harvard School of Public Health and co-author two studies of the two populations Ferre said.

A randomized clinical trial conducted in Barcelona in 2015 also found that a Mediterranean diet containing olive oil could “prevent age-related cognitive decline” in older adults. “Olive oil is rich in monounsaturated fat and contains antioxidant compounds that protect the brain,” says Guache-Perret.

Anne-Julie Tessier, a nutrition researcher at Harvard’s TH Chan School of Public Health and senior author of the study, said olive oil “can cross the blood-brain barrier and benefit the brain directly . ” on heart health and indirectly supports the brain.

■ How to research

More than 92,000 participants in two groups answered questions about how often they ate different foods every four years over a 28-year period starting in 1990. Respondents recorded how often they using olive oil at home when making food such as salad dressing, bread, baking or frying.

Researchers reviewed the death certificates of participants who died during the study period to determine whether depression was the cause of death, and found that 4,751 participants died of depression, said Tessier.

What we don’t know

Although observational studies have found an association between olive oil consumption and a relatively lower risk of death from dementia, researchers have not found a causal relationship.

“Interventional studies are needed to determine causal relationships and optimal olive oil intake,” explained Guache-Perret, adding that future studies could try to examine the mechanisms by which olive oil consumption reducing the risk of death from dementia. The study also looked at the diet of health professionals, so the results may not generalize to a wider and more diverse population.

In addition, the researchers were not able to distinguish between different types of olive oil, such as virgin or extra virgin, which contained more antioxidants, said Guache-Perret.

■ Other expert opinions

David Knobman, professor of neurology at the Mayo Clinic in Rochester, Minnesota, said this was a very good observational study, but noted that people who eat more olive oil may be more health conscious.

“This limitation is one of the real problems in interpreting dietary data,” said Knobman, who added that the results are “consistent with our preconceived notions of what should be in healthy diet.” There are many lifestyle factors that affect cardiovascular health and mental health, including exercise, diet, sleep, and smoking, and these factors are interrelated.

“The only way to prove the cause of a therapeutic intervention is through a randomized clinical trial,” said Knobman, who said he was “highly skeptical” that a single nutrient is the key to better health.

Vasilis Vasiliou, professor and chair of the Department of Environmental Health Sciences at the Yale School of Public Health, said the Harvard study was “carefully done” and did not explain why the oil might have cardiovascular or cognitive health benefits. olive or other parts of the plant. He said major efforts were underway to “find the mechanism.”

“We don’t think it’s one or two compounds. “Olive oil contains phenolic antioxidants, which are very important in protecting against oxidative stress,” explained Vasiliou, “but there are many others,” he admits.

■ What we can do

Guache-Perret said choosing olive oil over processed fats such as margarine or mayonnaise is a safe choice and may reduce the risk of fatal dementia. Tessie also said that if you can afford it, it’s a good idea to choose vegetable oil, especially olive oil or extra virgin olive oil.

“Extra virgin olive oil is actually higher in polyphenols,” she says, “components that are beneficial for brain health than processed fats.”

Vasiliou said he drinks two tablespoons of olive oil, which is high in polyphenols, every morning and cooks with olive oil every day “You can laugh, but sometimes I even sprinkling olive oil on top of ice cream. ”

By Teddy Amenabar>