Harvard T.H. Chan School of Public Health’s study found that eating olive oil reduces adult mortality. Specifically, the findings revealed that eating over a half-tablespoon of olive oil lowered the risk of several diseases. When adults ate this amount of oil in their diet, their risk of cancer, neurodegenerative, cardiovascular, and respiratory disease mortality declined.

Additionally, the authors found that substituting about 10 grams/day of dairy fats like margarine, butter, and mayonnaise with an equivalent amount of olive oil lowered mortality risk.

The study results appear in the Journal of the American College of Cardiology.

“Our findings support current dietary recommendations to increase the intake of olive oil and other unsaturated vegetable oils,” said Marta Guasch-Ferré, Ph.D., a senior research scientist at the Department of Nutrition at Harvard T.H. Chan School of Public Health and the study’s lead author.

“Clinicians should be counseling patients to replace certain fats, such as 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.”

Study Reveals That Eating Olive Oil Lowers Adult Mortality Rate

eating olive oil

The team recruited participants from the Nurses’ Health Study and the Health Professionals’ Follow-Up Study. In total, they analyzed health data from 60,582 women and 31,801 men who had no history of cardiovascular disease or cancer when the study began in 1990.

Throughout 28 years of follow-up, the participants reported any dietary changes in questionnaires. They answered how often they consumed certain foods, such as fats and oils. Besides that, they tracked which brands and types they used for cooking.

Researchers calculated olive oil consumption by totaling three items in the questionnaire. They took the sum of olive oil used for salad dressings, olive oil added to food or bread, and olive oil used for baking or frying. One tablespoon equaled 13.5 grams of olive oil.

They also measured the participants’ consumption of other vegetable oils based on the brand and type used for cooking.

Additionally, the team considered margarine and butter intake based on the reported stick, tub, or soft margarine consumption. They also added the amount of margarine or butter participants used for baking or frying. Finally, they totaled the participants’ consumption of other dairy, fats, and nutrients.

After analyzing these results, the team discovered that olive oil consumption increased from 1.6 grams/day in 1990 to nearly 4 grams/day in 2010. On the other hand, margarine consumption declined from about 12 grams/ day in 1990 to nearly 4 grams/day in 2010. The intake of other types of fats stayed the same.

Researchers categorized olive oil consumption using these metrics:

  • Never or <1 time per month
  • >0 to ≤4.5 grams/day (>0 to ≤1 teaspoon)
  • >4.5 to ≤7 grams/day (>1 teaspoon to ≤1/2 tablespoon)
  • >7 grams/day (>1/2 tablespoon)

Throughout the 28-year follow-up period, 36,856 deaths occurred: 22,768 in the Nurses’ Health Study and 14,076 in the Health Professionals Study. Researchers noted a few main differences between those who consumed higher amounts of olive oil and those who ate little.

Key Findings from the Study on Eating Olive Oil

Participants with high olive oil intake usually exercised frequently, didn’t smoke, ate more fruits and vegetables, and had Southern European or Mediterranean heritage. In the highest category, average total olive oil consumption measured about 9 grams/day at baseline. However, this included just 5% of the study volunteers.

Researchers then compared those who rarely or never ate olive oil with those in the highest consumption category. Participants eating a half-tablespoon or more of olive oil per day had remarkable health benefits. Their risk of cardiovascular, cancer, neurodegenerative, and respiratory mortality declined by 19%, 17%, 29%, and 18%, respectively.

Also, the study found that replacing about 10 grams/day of dairy fats with olive oil lowered total and cause-specific mortality risk by 8-34%. However, they didn’t note any differences when substituting olive oil for other vegetable oils.

What the experts said about eating olive oil:

“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 minimize potentially confounding socioeconomic factors, but may limit generalizability as this population may be more likely to lead a healthy lifestyle.”

While it’s necessary to perform additional studies with a larger population, these results confirm the health benefits of olive oil. Doctors have been touting the oil for years for its ability to lower heart disease risk, ease inflammation and provide healthy fats. However, this study leaves a few unanswered questions.

In an accompanying editorial, Susanna C. Larsson, Ph.D., associate professor of epidemiology at the Karolinska Institutet in Stockholm, said the following:

“The current study and previous studies have found that consumption of olive oil may have health benefits. However, several questions remain. Are the associations causal or spurious? Is olive oil consumption protective for certain cardiovascular diseases, such as stroke and atrial fibrillation, only or also for other major diseases and causes of death? What is the amount of olive oil required for a protective effect? More research is needed to address these questions.”

eating olive oil

Final Thoughts on Study That Explains the Relationship Between Eating Olive Oil and Better Health

You’re probably much healthier if you have high olive oil consumption. A new study shows that eating a half-tablespoon each day can greatly reduce adult mortality rates. Specifically, researchers found that high olive oil consumption declined mortality rates for cancer and neurodegenerative, respiratory, and cardiovascular diseases.

It’s quite easy to fit olive oil into your diet, as it’s versatile and complements many dishes. Try it on salads, roasted or sautéed vegetables, or even as a substitute for butter in baked goods. No matter how you enjoy it, you can feel good knowing it’s boosting your health.