Reference: Tessier A-J, Cortese M, Yuan C, et al. Consumption of olive oil and dietary quality and risk of dementia-related death. JAMA Network Open. 2024;7(5):e2410021. doi:10.1001/jamanetworkopen.2024.10021.
A recently published analysis of two large, long-term studies found that consuming half a tablespoon or more of olive oil per day lowered the risk of dying of dementia by up to 34% in both women and men. The protective effect of olive oil consumption was even greater in women.
More than 92,000 participants from the Nurses’ Health Study (NHS) and the Health Professionals Follow-Up Study (HPFS) were included in this analysis. The NHS started in 1976 and enrolled 121,700 female registered nurses (ages 30–55). The HPFS began in 1986 as a similar study in men, enrolling 51,525 male healthcare professionals (ages 40–75).
Study participants responded every other year to detailed food frequency questionnaires (FFQ) about their consumption of specific foods. Questions about olive oil were added in 1990. Total olive oil intake was determined by three responses: olive oil used for salad dressings, olive oil added to food or bread, and olive oil used for baking or frying at home.
Olive oil intake frequency was categorized as follows:
• Never, or less than once per month
• Less than 4.5 grams (about one teaspoon) per day
• Between 4.5 and 7 grams per day
• More than 7 grams (about half a tablespoon) per day
About two-thirds of the study participants (65.6%) were women, about a third (34.4%) were men, and the average age at the start of the study was 56 years. Each participant’s FFQs from 1990 to 2014 (or for as long as the participant remained in the study) were totaled and averaged. Average olive oil intake was 1.3 grams per day in both studies.
Participants in the highest olive oil intake group—half a tablespoon or more of olive oil per day— reduced their risk of dying of dementia by 28% to 34%, compared to study participants who never or very rarely consumed olive oil. These results were regardless of other dietary habits and factored in socio-demographic and lifestyle differences.
Deaths due to dementia were confirmed by physician’s review of medical records, autopsy reports, or death certificates of study participants.
It has been proposed that consuming olive oil may lower the risk of dementia-related death by improving blood vessel health, yet the results of this analysis were not impacted by hypertension or high cholesterol in participants.
Limitations of this analysis include its predominantly non-Hispanic white population of healthcare professionals, which reduces the ability to generalize these results across more diverse populations. Also, the FFQs did not dis-tinguish among types of olive oil, which differ in their amounts of polyphenols and other bioactive compounds.