[Column] Olive oil and dementia mortality risk

Is increasing olive oil consumption beneficial, even if you don’t follow the Mediterranean diet? A new study suggests it could be. Researchers from the Harvard School of Public Health, in a study published in May 2024, found that daily olive oil intake is linked to a lower risk of death from dementia.

Those who consumed 7 grams or more of olive oil daily had a 28 percent lower risk of death from dementia compared to those with little or no olive oil consumption. Regardless of the participants' overall diet quality or adherence to the Mediterranean diet, higher olive oil intake was associated with a lower risk of dementia death. This suggests that instead of prioritizing fruits, vegetables, whole grains, nuts, fish, and chicken, simply adding 1.5 tablespoons of olive oil—even to something like ice cream—reduced the risk of dementia death.

The study surveyed more than 92,000 participants every four years for 28 years, starting in 1990, asking how often they consumed various foods. Participants were asked to report how frequently they used olive oil in salad dressings, on food or bread, or for baking or frying at home over the past year. Of the participants, 65 percent were women and nurses, while the men were health professionals such as dentists, pharmacists, and veterinarians. Over the 28-year study, 4,751 participants were identified as having died from dementia. Analysis of these deaths revealed an association between olive oil consumption and a lower risk of dementia-related death.

However, the study had several limitations. First, it focused solely on a specific group—health professionals—making it difficult to generalize the findings to the broader population. Additionally, as an observational study, it cannot prove that olive oil consumption directly caused a lower risk of dementia death. While replacing 5 grams of margarine or mayonnaise per day with the same amount of olive oil was linked to an 8-14 percent lower risk of dementia death, no significant difference was found when replacing butter or other vegetable oils with olive oil. To definitively confirm that olive oil reduces the risk of dementia death, a randomized controlled trial would be necessary. However, such a trial would be impractical due to the time and cost involved in providing one group with daily olive oil capsules and another with regular cooking oil and then comparing dementia death rates over many years.

Olive oil’s potential benefits may stem from its higher content of monounsaturated fatty acids and antioxidants, such as polyphenols, which have been linked to a lower risk of dementia death. However, it's also possible that those who consume more olive oil tend to be more health-conscious overall. More studies are needed to clarify the relationship. In the meantime, there's no need to choose between the two approaches. You can use olive oil in your cooking whenever possible while also adopting a more health-conscious lifestyle. Taking care of your health may be simpler than you think.

Jeong Jae-hoon is a food writer and pharmacist. He covers a variety of subjects, including trends in food, wellness and medications. This column was originally published in Korean in Joongang Ilbo on Aug. 15, 2024. – Ed.