Originally published January 13, 2022 · Updated August 2026
Reviewed by Dr. Limor Goren, PhD
The short version
In a Harvard study of 92,383 US adults followed for 28 years, people who consumed more than half a tablespoon of olive oil per day (more than 7 grams) had a 19% lower risk of death from any cause than people who rarely or never used it. The strongest association was with neurodegenerative disease, at 29% lower risk.
A Harvard study of more than 90,000 US healthcare professionals, published January 10, 2022 in the Journal of the American College of Cardiology, found that consuming even a small amount of olive oil each day is associated with reduced mortality.
The study drew on two of the longest-running cohorts in nutrition research: 60,582 women from the Nurses' Health Study and 31,801 men from the Health Professionals Follow-up Study, all free of cardiovascular disease and cancer at baseline in 1990. Researchers compared men and women who rarely or never consumed olive oil to those who consumed more than half a tablespoon per day, across 28 years of follow-up. Participants with the higher intake had a 19% lower risk of all-cause mortality.
What the study found, cause by cause
| Cause of death | Risk reduction | Hazard ratio (95% CI) |
|---|---|---|
| All causes | 19% lower | 0.81 (0.78–0.84) |
| Cardiovascular disease | 19% lower | 0.81 (0.75–0.87) |
| Cancer | 17% lower | 0.83 (0.78–0.89) |
| Neurodegenerative disease | 29% lower | 0.71 (0.64–0.78) |
| Respiratory disease | 18% lower | 0.82 (0.72–0.93) |
Highest olive oil intake (more than 7 g per day) compared with never or rarely consuming olive oil. Guasch-Ferré et al., JACC 2022.
In a sensitivity analysis, the researchers also found a 27% lower risk of dementia-related mortality in the highest intake group compared with the lowest – a finding singled out as notable in the editorial that accompanied the paper. Given how few preventative strategies exist for Alzheimer's disease, that signal drew immediate attention.
It has since been examined directly. A 2024 study in JAMA Network Open, using the same two cohorts, found that more than 7 grams of olive oil per day was associated with a 28% lower risk of dementia-related death – and that the association held regardless of overall diet quality. We covered that study in detail here: Can Olive Oil Reduce the Risk of Dementia-related Death?
How much olive oil per day does this mean?
The threshold in this study was modest: more than 7 grams a day, roughly half a tablespoon. In substitution analyses, replacing 10 grams per day of margarine, butter, mayonnaise or dairy fat with the same amount of olive oil was associated with an 8% to 34% lower risk of death from various causes.
Marta Guasch-Ferré, PhD, a senior research scientist in the Department of Nutrition at the Harvard T.H. Chan School of Public Health, recommended using olive oil "for cooking, salad dressing, and baking" in place of saturated and animal fats.
For a fuller answer on daily amounts, including what the clinical trial literature suggests for high-phenolic oils specifically, see our guide: How much olive oil per day is a healthy dose?
Why extra virgin olive oil is important
The researchers confirmed that extra virgin olive oils contains minor bioactive compounds, including phenolic compounds and vitamin E, that are largely reduced during refining. These compounds are one reason researchers are interested in whether different olive oils may have different biological effects.
This is also where phenolic concentration becomes relevant. Not all extra virgin olive oil carries the same polyphenol load – kyoord's oils test between 1,007 and 2,012 mg/kg, and that characteristic peppery sensation at the back of the throat is particularly associated with oleocanthal, one of the phenolic compounds found in high-phenolic EVOO.
What this study does not show
This was an observational cohort study, not a clinical trial. It can show a strong, consistent association across a very large group of people over a very long time, but it cannot prove that olive oil caused the difference in mortality.
And while olive oil compared favorably against butter, margarine, mayonnaise and dairy fat, the researchers found no significant difference when olive oil was compared with other vegetable oils combined. The clearest takeaway is about what olive oil replaces.
Despite these limitations, the study is notable for both its size and its 28 years of follow-up, making it one of the most informative long-term studies of olive oil intake and mortality to date.
Frequently asked questions
How much olive oil per day did the study measure?
More than 7 grams per day, or just over half a tablespoon. That was the highest intake category, compared against people who never or rarely consumed olive oil.
Does olive oil reduce the risk of death?
Higher olive oil intake was associated with a 19% lower risk of all-cause mortality in this study. Because it is observational research, it demonstrates an association rather than proving cause and effect.
Does the type of olive oil matter?
Extra virgin olive oil retains polyphenols and Vitamin E that refined and processed olive oils lose. Early research suggests the polyphenol concentration itself influences the effect, which is why high-phenolic extra virgin olive oil is worth distinguishing from standard extra virgin.
References:
- Guasch-Ferré M, et al. Consumption of Olive Oil and Risk of Total and Cause-Specific Mortality Among U.S. Adults. J Am Coll Cardiol. 2022;79(2):101–112. doi:10.1016/j.jacc.2021.10.041
- Larsson SC. Editorial comment. J Am Coll Cardiol. 2022;79(2). doi:10.1016/j.jacc.2021.11.006
- Tessier A-J, et al. Consumption of Olive Oil and Diet Quality and Risk of Dementia-Related Death. JAMA Netw Open. 2024;7(5):e2410021. doi:10.1001/jamanetworkopen.2024.10021
- Harvard T.H. Chan School of Public Health, news release, January 10, 2022
