The objective of the work of Dr. Marta Guasch-Ferré and her associate colleagues at Harvard University was to evaluate from two prospective cohorts of men and women how olive oil consumption influences deaths. in general, but also on deaths related to specific causes
This type of cohort follows over time a group of similar individuals, whose habits with respect to certain factors differ, in order to determine how these latter influence certain aspects of their lives.
Our results support current dietary recommendations aimed at increasing the consumption of olive oil and other unsaturated vegetable oils., says in a press release Dr. Marta Guasch-Ferré, the main author of the study published in the Journal of the American College of CardiologyHave (New window)Have (in English).
Clinicians should advise their patients to replace certain fats, such as margarine and butter, with olive oil to improve their health, adds Dr. Guasch-Ferré.
” Our study allows for more specific recommendations that will be easier for patients to understand and hopefully implement into their diet. “
In their work, the researchers analyzed the records of participants who had no cardiovascular disease or cancer at the start of the cohorts in 1990. During the 28 years of follow-up, their eating habits were assessed by a questionnaire every four years. The volunteers were asked how often, on average, they ate certain foods, and the types of fats and oils they used in cooking.
The amount of olive oil they consumed was calculated from the sum of three items from the questionnaire: the olive oil used to dress the salad; olive oil added to food or bread; and olive oil used at home for cooking and frying.
In these works, one tablespoon was equivalent to 13.5 grams of olive oil.
The consumption of other vegetable oils and fats of dairy origin was also calculated.
Researchers found that olive oil consumption fell from 1.6 grams/day in 1990 to about 4 grams/day in 2010. Margarine consumption decreased from about 12 grams/day in 1990 to about 4 grams/day in 2010. Consumption of other fats remained stable.
Consumption of olive oil has been classified into four categories:
- Never or less than once a month
- From 0 to 4.5 grams / day (less than a teaspoon)
- 4.5 to 7 grams/day (one teaspoon to half a tablespoon)
- More than 7 grams/day (about half a tablespoon)
During the study, 36,856 of the participants died in both cohorts.
People in the highest category of olive oil consumption had a lower risk of death:
- 19% from cardiovascular disease;
- 17% by cancer;
- 29% by a neurodegenerative disease;
- 18% by respiratory disease.
In addition, the analysis also found that substituting 10 grams per day of other fats, such as margarine, butter, mayonnaise and dairy fat, with olive oil was associated with a 8% to 34% reduction in risk of death. No significant association was found when olive oil was replaced by other vegetable oils
Better general health
The data analyzed shows that people with a higher consumption of olive oil (5% of study participants) were often more physically active, and had Mediterranean origins. They were also less likely to smoke and consumed more fruits and vegetables compared to those with a lower consumption of olive oil.
It is 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 socioeconomic status factors, our results remained largely the same., says Dr. Guasch-Ferré.
Questions to clarify
For her part, Professor Susanna Larsson of the Karolinska Institute in Stockholm, who did not participate in this work, affirms in a commentary accompanying the study that this is added to the growing list of data showing that the consumption of olive oil has beneficial effects on health.
However, several questions remain. Are the associations causal or misleading? Does olive oil consumption only protect against certain cardiovascular diseases, such as stroke and atrial fibrillation, or also against other diseases and other major causes of death? And how much olive oil is needed to achieve a protective effect?, wonders Prof. Larsson, who believes that further research is needed to answer these questions.