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More olive oil, less butter, reduces risk of CVD mortality – large Harvard analysis

Consuming more than 7g (>1/2 tablespoon) of olive oil daily has been linked to a lower risk of cardiovascular disease mortality, cancer mortality, neurodegenerative disease mortality and respiratory disease mortality, according to a study published in the Journal of the American College of Cardiology. The study found that replacing about 10g/day of margarine, butter, mayonnaise and dairy fat with the equivalent amount of olive oil is associated with lower risk of mortality as well.

“Our findings support current dietary recommendations to increase the intake of olive oil and other unsaturated vegetable oils,” said Marta Guasch-Ferré, PhD, a senior research scientist at the Department of Nutrition at Harvard TH Chan School of Public Health and the study’s lead author. “Clinicians should be counseling patients to replace certain fats, like margarine and butter, with olive oil to improve their health. Our study helps make more specific recommendations that will be easier for patients to understand and hopefully implement into their diets.”

Using participants from the Nurses’ Health Study and the Health Professionals Follow-up Study, researchers analysed 60,582 women and 31,801 men who were free of cardiovascular disease and cancer at the study baseline in 1990. During 28 years of follow-up, diet was assessed by a questionnaire every four years. The questionnaire asked how often, on average, they consumed specific foods, types of fats and oils, as well as which brand or type of oils they had used for cooking and added at the table in the previous year.

Olive oil consumption was calculated from the sum of three items in the questionnaire: olive oil used for salad dressings, olive oil added to food or bread, and olive oil used for baking and frying at home. One tablespoon was equivalent to 13.5g of olive oil. The consumption of other vegetable oils was calculated based on the participants’ reported oil brand and type of fat used for cooking at home. Margarine and butter consumption was based on the reported frequency of stick, tub or soft margarine consumption, and the amount of margarine or butter added from baking and frying at home. Intakes of dairy and other fats and nutrients were also calculated. The researchers found olive oil consumption increased from 1.6g /day in 1990 to about 4g /day in 2010, while margarine consumption decreased from about 12g /day in 1990 to about 4g /day in 2010. The intake of other fats remained stable.

Olive oil consumption was categorised as follows:
• Never or <1 time per month • >0 to ≤4.5g /day (>0 to ≤1 teaspoon)
• >4.5 to ≤7g /day (>1 teaspoon to ≤1/2 tablespoon)
• >7g /day (>1/2 tablespoon)

Over the course of 28 years, there were 36,856 deaths, with 22,768 occurring in the Nurses' Health Study, and 14,076 in the Health Professionals Follow-up Study.

Participants with higher olive oil consumption were often more physically active, had Southern European or Mediterranean ancestry, were less likely to smoke and had a greater consumption of fruits and vegetables compared with those with lower olive oil consumption. The average consumption of total olive oil in the highest category was about 9g /day at baseline and included 5% of the study participants.

When researchers compared those who rarely or never consumed olive oil, those in the highest consumption category had 19% lower risk of cardiovascular mortality, 17% lower risk of cancer mortality, 29% lower risk of neurodegenerative mortality and 18% lower risk of respiratory mortality. The study also found substituting 10g /day of other fats, such as margarine, butter, mayonnaise and dairy fat, with olive oil was associated with 8-34% lower risk of total and cause-specific mortality. They found no significant associations when substituting olive oil for other vegetable oils.

“It’s possible that higher olive oil consumption is a marker of an overall healthier diet and higher socioeconomic status. However, even after adjusting for these and other social economic status factors, our results remained largely the same,” Guasch-Ferré said. “Our study cohort was predominantly a non-Hispanic white population of health professionals, which should minimise potentially confounding socioeconomic factors, but may limit generalisability as this population may be more likely to lead a healthy lifestyle.”

Study details
Consumption of Olive Oil and Risk of Total and Cause-Specific Mortality Among US Adults

Marta Guasch-Ferré, Yanping Li, Walter C. Willett, Qi Sun, Laura Sampson, Jordi Salas-Salvadó, Miguel A. Martínez-González, Meir J. Stampfer, Frank B. Hu.

Published in the Journal of the American College of Cardiology on 18 January 2022.

Abstract

Background
Olive oil consumption has been shown to lower cardiovascular disease risk, but its associations with total and cause-specific mortality are unclear.

Objectives
The purpose of this study was to evaluate whether olive oil intake is associated with total and cause-specific mortality in 2 prospective cohorts of U.S. men and women.

Methods
The authors used multivariable-adjusted Cox proportional-hazards models to estimate HRs for total and cause-specific mortality among 60,582 women (Nurses’ Health Study, 1990-2018) and 31,801 men (Health Professionals Follow-up Study, 1990-2018) who were free of cardiovascular disease or cancer at baseline. Diet was assessed by a semiquantitative food frequency questionnaire every 4 years.

Results
During 28 years of follow-up, 36,856 deaths occurred. The multivariable-adjusted pooled HR for all-cause mortality among participants who had the highest consumption of olive oil (>0.5 tablespoon/day or >7 g/d) was 0.81 (95% CI: 0.78-0.84) compared with those who never or rarely consumed olive oil. Higher olive oil intake was associated with 19% lower risk of cardiovascular disease mortality (HR: 0.81; 95% CI: 0.75-0.87), 17% lower risk of cancer mortality (HR: 0.83; 95% CI: 0.78-0.89), 29% lower risk of neurodegenerative disease mortality (HR: 0.71; 95% CI: 0.64-0.78), and 18% lower risk of respiratory disease mortality (HR: 0.82; 95% CI: 0.72-0.93). In substitution analyses, replacing 10 g/d of margarine, butter, mayonnaise, and dairy fat with the equivalent amount of olive oil was associated with 8%-34% lower risk of total and cause-specific mortality. No significant associations were observed when olive oil was compared with other vegetable oils combined.

Conclusions
Higher olive oil intake was associated with lower risk of total and cause-specific mortality. Replacing margarine, butter, mayonnaise, and dairy fat with olive oil was associated with lower risk of mortality.

 

JACC article – Consumption of Olive Oil and Risk of Total and Cause-Specific Mortality Among US Adults (Open access)

 

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