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Association of Consumption of Olive Oil and Diet Quality With the Risk of Dementia-Related Death
abstract
This abstract is available on the publisher's site.
Access this abstract nowIMPORTANCE
Age-standardized dementia mortality rates are on the rise. Whether long-term consumption of olive oil and diet quality are associated with dementia-related death is unknown.
OBJECTIVE
To examine the association of olive oil intake with the subsequent risk of dementia-related death and assess the joint association with diet quality and substitution for other fats.
DESIGN, SETTING, AND PARTICIPANTS
This prospective cohort study examined data from the Nurses' Health Study (NHS; 1990-2018) and Health Professionals Follow-Up Study (HPFS; 1990-2018). The population included women from the NHS and men from the HPFS who were free of cardiovascular disease and cancer at baseline. Data were analyzed from May 2022 to July 2023.
EXPOSURES
Olive oil intake was assessed every 4 years using a food frequency questionnaire and categorized as (1) never or less than once per month, (2) greater than 0 to less than or equal to 4.5 g/d, (3) greater than 4.5 g/d to less than or equal to 7 g/d, and (4) greater than 7 g/d. Diet quality was based on the Alternative Healthy Eating Index and Mediterranean Diet score.
MAIN OUTCOME AND MEASURE
Dementia death was ascertained from death records. Multivariable Cox proportional hazards regressions were used to estimate hazard ratios (HRs) and 95% CIs adjusted for confounders including genetic, sociodemographic, and lifestyle factors.
RESULTS
Of 92 383 participants, 60 582 (65.6%) were women and the mean (SD) age was 56.4 (8.0) years. During 28 years of follow-up (2 183 095 person-years), 4751 dementia-related deaths occurred. Individuals who were homozygous for the apolipoprotein ε4 (APOE ε4) allele were 5 to 9 times more likely to die with dementia. Consuming at least 7 g/d of olive oil was associated with a 28% lower risk of dementia-related death (adjusted pooled HR, 0.72 [95% CI, 0.64-0.81]) compared with never or rarely consuming olive oil (P for trend < .001); results were consistent after further adjustment for APOE ε4. No interaction by diet quality scores was found. In modeled substitution analyses, replacing 5 g/d of margarine and mayonnaise with the equivalent amount of olive oil was associated with an 8% (95% CI, 4%-12%) to 14% (95% CI, 7%-20%) lower risk of dementia mortality. Substitutions for other vegetable oils or butter were not significant.
CONCLUSIONS AND RELEVANCE
In US adults, higher olive oil intake was associated with a lower risk of dementia-related mortality, irrespective of diet quality. Beyond heart health, the findings extend the current dietary recommendations of choosing olive oil and other vegetable oils for cognitive-related health.
Additional Info
Disclosure statements are available on the authors' profiles:
Consumption of Olive Oil and Diet Quality and Risk of Dementia-Related Death
JAMA Netw Open 2024 May 01;7(5)e2410021, AJ Tessier, M Cortese, C Yuan, K Bjornevik, A Ascherio, DD Wang, JE Chavarro, MJ Stampfer, FB Hu, WC Willett, M Guasch-FerréFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Oliver oil and risk of dementia mortality
The Nurses’ Health and the Health Professionals Follow-Up cohorts were followed for 28 years. Every 4 years, 92,383 participants were asked to share the amount of olive oil consumed daily. Death from dementia was the primary outcome. Compared with those who never or rarely consumed olive oil, using more than 7 g/day was associated with a 28% reduction in risk of dementia-related death. Substituting 5 g of mayonnaise or margarine was associated with an 8% reduction in dementia mortality.
A single tablespoon is equivalent to 13.5 g of olive oil; 7 g is about half a tablespoon, or 1.5 teaspoons daily. The authors suggest that olive oil has neuroprotective benefits through its phenolic compounds, which reduce inflammation and oxidation, protecting the blood–brain barrier. Olive oil has been found to improve endothelial function through improved lipid metabolism and coagulation. Extra-virgin olive oil has a higher percentage of phenols.
Olive oil, as part of a Mediterranean diet can help prevent dementia, but other foods can increase the risk. The Three-City Study used network science to show that red and processed meat along with simple carbohydrates found in bread were associated with an increased risk.1 The UK Biobank study showed that ultra-processed food was associated with dementia. If 20% of these foods were replaced with unprocessed whole foods, the risk would be reduced by 34%.2 The UK Biobank also showed that drinking more than 15 g of alcohol daily (about a pint of beer) has a linear dose correlation with loss of gray matter over time with MRI monitoring.3
The studies mentioned above were all done in Europe where the nutritional habits are generally healthier than in America. This study was done in America showing significant potential with only one food source in a nation whose dietary habits have room for improvement.
The effectiveness of the medications we have for treating dementia is small at best. But the growing evidence of the benefits and risks of nutrition give credence to the adage, let food be thy medicine.
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