In an observational study of more than 90,000 US healthcare professionals, consumption of even a small amount of olive oil was associated with reduced overall mortality.
Compared with men and women who rarely or never consumed olive oil (the lowest intake), those who consumed more than 0.5 tablespoons / day or more than 7 g / day (the highest intake) had a 19% lower mortality risk over a 28-year period. one-year follow-up, starting with a mean age of 56 years.
Furthermore, compared to those with the lowest olive oil intake, those with the highest intake had a 19% lower mortality from cardiovascular disease (CVD), a 17% lower risk of dying from cancer, a 29% lower risk of dying from neurodegenerative disease, and 18% lower risk of dying from respiratory disease during follow-up.
Researchers estimate that replacing 10 g / day of margarine, butter, mayonnaise, or milk fat with the same amount of olive oil is associated with an 8% to 34% lower risk of death from various causes.
The study by Marta Guasch-Ferré, PhD, and colleagues was Posted online January 10 at the Journal of the American College of Cardiology.
Results Support Plant-Based Dietary Fat Recommendations
“Our results support current dietary recommendations to increase your intake of olive oil and other unsaturated vegetable oils in place of other fats to improve overall health and longevity,” the researchers summarize.
However, “I would not say that olive oil is the only way to help you live longer,” he warned in an interview with theheart.org | Medscape Cardiology.
“Other things are very important, such as not smoking, doing physical activity, etc., but a recommendation could be to try to eat more plant-based foods such as olive oil and healthy fats,” he adds, and use it for cooking. salad dressing and baking and substitute saturated fat or animal fat, especially for cooking.
The study suggests that people should “eat a more plant-based diet and prioritize fatty acids like olive oil because they have a better nutritional composition (high in phenols and antioxidants), rather than using butter or margarines or other animal fats. they have been shown to have detrimental health effects, “he added, which is consistent with the recommendations of the Dietary Guidelines for Americans.
“That said,” Guasch-Ferré summarized, “replication in other cohorts and populations is needed to see if the results are similar.”
in a accompanying editorialSusanna C. Larsson, PhD, writes that “this was a well-designed study, with long-term follow-up and repeated measurements of dietary intake and other risk factors for disease.”
“However, the difference in olive oil consumption between those with the highest and the lowest / no olive oil consumption was very low (0.5 tablespoon) and a [12%] A reduced risk of mortality has already been observed with a much lower intake (0.5 teaspoons, about 1.5 g / day) of olive oil, “he noted in an email to theheart.org | Medscape Cardiology.
“It’s a bit hard to believe that such a small amount could have an independent effect on mortality risk,” warned Larsson, associate professor of epidemiology at the Karolinska Institute in Stockholm, Sweden.
Like Guasch-Ferré, he noted that “just adding a teaspoon or two of olive oil to the diet every day probably won’t change the risk of mortality.”
Rather, “People may need to make bigger changes to the entire diet, not just focus on fats. A healthier diet overall, rich in unrefined plant-based foods (vegetables, whole grains, nuts), low or no intake of processed foods, and a switch to healthier fats (eg, olive oil) is needed.
Importantly, “this study cannot say anything about causation, that is, whether it is olive oil specifically that reduces the risk of mortality or whether there are many other beneficial factors that work together to reduce the mortality rate among women. people with high consumption of olive oil “.
The researchers acknowledge this limitation of the observational study and that the findings may not be generalizable to other populations.
Novel findings about Alzheimer’s and respiratory diseases
Larsson highlights two novel findings from this study.
First, it showed a 27% reduction in the risk of dementia-related mortality for those in the highest versus lowest category of olive oil consumption. “Considering the lack of preventive strategies to Alzheimer disease and the high morbidity and mortality related to this disease, this finding, if confirmed, is of great importance for public health ”, he said.
Second, the study reported an inverse association of olive oil consumption with the risk of mortality from respiratory diseases. “Since residual confusion from smoking cannot be ruled out,” Larsson said, “this finding is tentative and requires confirmation in a study that is less susceptible to confusion, such as a randomized trial.”
And while the current study and previous studies have found that consuming olive oil may have health benefits, it did identify several outstanding questions.
“Are the associations causal or spurious?” she noticed. Does the consumption of olive oil protect against certain cardiovascular diseases such as race or atrial fibrillation alone, as other studies have shown, or for other major diseases and causes of death as well, he added. What is the amount of olive oil necessary for a protective effect?
Also, is the potential effect related to monounsaturated fatty acids (MUFA) or phenolic compounds; that is, “Is the protective effect limited to polyphenol-rich extra virgin olive oil or are refined olive oil and other vegetable oils that beneficial? More research is needed to address these questions,” he concludes.
“More studies are needed,” the researchers agree, “to confirm the association of olive oil consumption with reduced mortality, clarify the responsible mechanisms and quantify the dose / volume limits around this effect.”
Virgin olive oil has more polyphenols
Olive oil, a key component of the Mediterranean diet, is high in MUFA, especially oleic acid, as well as Vitamin E and polyphenols, which contribute to its anti-inflammatory and antioxidant properties, the researchers explain.
Virgin olive oil, obtained from the mechanical pressing of ripe olives, contains multiple bioactive and antioxidant components and has an acidity <1.5%. And extra virgin olive oil is produced in the same way but it has a higher quality, a more intense flavor and a lower acidity (<1%).
Refined or processed olive oil contains fewer phytochemicals, as some are lost during processing; it typically contains more than 80% refined oil, plus virgin oil added to enhance flavor, and can also be labeled “pure” or “light.” However, refined olive oil “still has a good amount of healthy fatty acids, but fewer bioactive compounds,” Guasch-Ferré noted.
So far, no large prospective study has examined the link between olive oil intake and all-cause and cause-specific mortality in a US population, where olive oil consumption is limited compared to Mediterranean countries.
Researchers identified 60,582 women in the Nurses’ Health Study and 31,801 men in the Health Professionals Follow-up Study who were free of CVD or cancer in 1990, the first year that food frequency questionnaires in these studies asked about olive oil.
Participants answered questionnaires every 4 years asking about the use of olive oil (for dressing salads, baking, frying, sautéing, and spreading bread), other vegetable oils (eg, corn oil, safflower, soybean, canola) , margarine, butter and milk fat. The researchers averaged the consumption of these fats over the years of follow-up.
From 1990 to 2019, the average consumption of olive oil went from 1.6 g / day to 4 g / day. In the 1990s, margarine contained saturated fat and trans fat, while more recently margarine contains beneficial olive oil or vegetable fat, Guasch-Ferré noted.
Basal olive oil consumption in this US population “differed significantly” from that of the Spanish population in the PREDIMED (Prevention with Mediterranean Diet) trial, which was, on average, 20 to 22 g / day of extra virgin olive oil and 16 to 18 g / day of refined / mixed olive oil, Larsson noted.
Because olive oil consumption was so low in this US study, the researchers did not distinguish between virgin / extra virgin olive oil and refined / processed olive oil.
The participants were nearly all white (99%) and generally healthier than the average US population; on average, they had a body mass index of 25.3 to 25.8 kg / mtwo and ate 4.8 to 7.2 fruits and vegetables / day.
Those with the highest olive oil consumption were more physically active, had a healthier diet, were more likely to be of southern European or Mediterranean descent, and less likely to smoke.
During 28 years of follow-up, 36,856 participants died. The researchers classified the deaths into five categories: cardiovascular disease, cancer, neurodegenerative diseases (including Alzheimer’s disease, Parkinson’s disease, multiple sclerosis), respiratory diseases (such as chronic obstructive pulmonary disease) and all other causes (including suicide, injury, infections, diabetes and kidney disease).
After adjusting for multiple confounders, compared to participants who rarely or never consumed olive oil, those in the highest quartile for olive oil consumption had a lower risk of death from all causes (ratio of risk [HR], 0.81; 95% CI, 0.78 – 0.84) and CVD (HR, 0.81, 95% CI, 0.75 – 0.87), cancer (HR, 0.83, 95% CI, 0.78 – 0.89), neurodegenerative disease (HR, 0.71; 95% CI, 0.64 – 0.78), and respiratory disease (HR, 0.82; 95% CI, 0.72 – 0.93).
There was no decrease in mortality in the models in which the researchers substituted olive oil for vegetable oil, suggesting that vegetable oils may provide similar health benefits to olive oil.
The research was supported by grants from the National Institutes of Health. Guasch-Ferré received support from the American Diabetes Association. The co-author Salas-Salvadó has the partial support of the Catalan Institution for Research and Advanced Studies and received the virgin olive oil that was used in the PREDIMED and PREDIMED-Plus studies of the Olivalero and Hojiblanca Communal Heritage (Málaga, Spain). The other study authors and Larsson have reported no relevant financial relationships.
J Am Coll Cardiol. Published online January 10, 2022. Abstract, Editorial
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