Can Olive Oil Help Reduce Breast Cancer Risk?
Breast cancer is one of the most common cancers affecting women, so it is understandable that researchers continue to look closely at the role lifestyle and diet may play in reducing risk.
One area that has attracted particular interest is the Mediterranean diet and, within it, extra virgin olive oil.
Research does not suggest that olive oil is a treatment for breast cancer, nor that any one food can prevent the disease.
The evidence shows something more interesting.
Human studies have repeatedly explored whether greater olive-oil consumption, or following a Mediterranean diet rich in extra virgin olive oil, is associated with a lower risk of breast cancer. At the same time, laboratory and animal research is helping scientists understand how individual olive-oil phenolics such as oleocanthal may interact with breast-cancer cells and biological pathways involved in tumour growth, migration and recurrence.
One area that has attracted particular interest is the Mediterranean diet and, within it, extra virgin olive oil.
Research does not suggest that olive oil is a treatment for breast cancer, nor that any one food can prevent the disease.
The evidence shows something more interesting.
Human studies have repeatedly explored whether greater olive-oil consumption, or following a Mediterranean diet rich in extra virgin olive oil, is associated with a lower risk of breast cancer. At the same time, laboratory and animal research is helping scientists understand how individual olive-oil phenolics such as oleocanthal may interact with breast-cancer cells and biological pathways involved in tumour growth, migration and recurrence.
And The Governor has played a direct role in part of that scientific story.
What does the human research say about olive oil and breast cancer?
The human evidence is encouraging, though not entirely uniform.
One of the strongest studies comes from PREDIMED, the large Spanish randomised clinical trial investigating the Mediterranean diet.
A breast-cancer analysis involved 4,152 women aged 60 to 80 who had no previous history of breast cancer.
One of the strongest studies comes from PREDIMED, the large Spanish randomised clinical trial investigating the Mediterranean diet.
A breast-cancer analysis involved 4,152 women aged 60 to 80 who had no previous history of breast cancer.
They were randomly assigned to one of three groups:
- A Mediterranean diet supplemented with extra virgin olive oil
- A Mediterranean diet supplemented with mixed nuts
- A control diet with advice to reduce dietary fat
After a median follow-up of 4.8 years, 35 cases of breast cancer had been confirmed.
The incidence rates were:
- 1.1 cases per 1,000 person-years in the Mediterranean diet plus EVOO group
- 1.8 in the Mediterranean diet plus nuts group
- 2.9 in the control group
Compared with the control group, the Mediterranean diet supplemented with EVOO was associated with a substantially lower incidence of breast cancer.
The adjusted hazard ratio was 0.32, equivalent to an estimated 68% lower relative risk in this analysis.
That sounds dramatic, but the researchers themselves urged caution. Breast cancer was a secondary outcome of the wider PREDIMED trial and there were only 35 cases in total.
So this study should not be interpreted as proof that EVOO prevents breast cancer.
It does, however, provide important randomised human evidence suggesting that a Mediterranean dietary pattern rich in extra virgin olive oil may be associated with a lower incidence of the disease.
Research: Mediterranean Diet and Invasive Breast Cancer Risk Among Women at High Cardiovascular Risk in the PREDIMED Trial: A Randomized Clinical Trial
https://pubmed.ncbi.nlm.nih.gov/26365989/
The adjusted hazard ratio was 0.32, equivalent to an estimated 68% lower relative risk in this analysis.
That sounds dramatic, but the researchers themselves urged caution. Breast cancer was a secondary outcome of the wider PREDIMED trial and there were only 35 cases in total.
So this study should not be interpreted as proof that EVOO prevents breast cancer.
It does, however, provide important randomised human evidence suggesting that a Mediterranean dietary pattern rich in extra virgin olive oil may be associated with a lower incidence of the disease.
Research: Mediterranean Diet and Invasive Breast Cancer Risk Among Women at High Cardiovascular Risk in the PREDIMED Trial: A Randomized Clinical Trial
https://pubmed.ncbi.nlm.nih.gov/26365989/
What have larger reviews found?
When researchers combine the available studies, the overall picture remains encouraging.
A 2022 systematic review and meta-analysis examined 45 studies, including 37 case-control studies and eight cohort studies.
Across the studies, people with the highest olive-oil consumption had a lower likelihood of several cancers.
For breast cancer specifically, the pooled relative risk was 0.67, meaning that the highest olive-oil intake was associated with a roughly 33% lower likelihood of breast cancer compared with the lowest intake.
That does not mean olive oil itself caused the reduction.
Much of the available evidence comes from observational research, where people who consume more olive oil may also differ in other important ways, including their overall diet, physical activity, body weight and lifestyle.
Even so, a consistent association across a number of studies gives researchers good reason to continue investigating the relationship.
A 2022 systematic review and meta-analysis examined 45 studies, including 37 case-control studies and eight cohort studies.
Across the studies, people with the highest olive-oil consumption had a lower likelihood of several cancers.
For breast cancer specifically, the pooled relative risk was 0.67, meaning that the highest olive-oil intake was associated with a roughly 33% lower likelihood of breast cancer compared with the lowest intake.
That does not mean olive oil itself caused the reduction.
Much of the available evidence comes from observational research, where people who consume more olive oil may also differ in other important ways, including their overall diet, physical activity, body weight and lifestyle.
Even so, a consistent association across a number of studies gives researchers good reason to continue investigating the relationship.
Research: Olive oil intake and cancer risk: A systematic review and meta-analysis
https://pubmed.ncbi.nlm.nih.gov/35015763/
What did earlier population studies find?
Interest in olive oil and breast cancer goes back several decades.
A 1995 Greek study compared 820 women with breast cancer with 1,548 women without the disease.
Women who consumed olive oil more than once a day had a significantly lower breast-cancer risk than those consuming it once daily.
The reported odds ratio was 0.75, suggesting around a 25% lower likelihood in the higher-consumption group.
The study also found favourable associations for higher vegetable and fruit intake.
Again, this was observational research, so it cannot show cause and effect.
But it helped establish an early epidemiological connection between traditional Mediterranean eating habits, olive oil and breast health.
Research: Consumption of Olive Oil and Specific Food Groups in Relation to Breast Cancer Risk in Greece
https://academic.oup.com/jnci/article-abstract/87/2/110/946863
Is all the human evidence positive?
No — and this is where a balanced interpretation matters.
Not every prospective study has found a significant association between olive oil consumption and overall breast-cancer risk.
For example, research from the European Prospective Investigation into Cancer and Nutrition, or EPIC, followed women in Mediterranean countries and did not find a clear association between total olive-oil intake and overall breast-cancer incidence.
However, some evidence suggested that olive oil might relate differently to particular tumour types, including hormone-receptor-negative cancers.
A separate systematic review and dose-response meta-analysis published in 2020 also concluded that an inverse association may exist, but the evidence was very uncertain and better prospective research is needed.
So the fairest conclusion is not that olive oil has been proven to prevent breast cancer.
It is that human studies repeatedly suggest a potentially favourable association, with some of the strongest evidence coming from Mediterranean populations and the PREDIMED randomised trial.
Why might extra virgin olive oil be different from other fats?
Extra virgin olive oil is not simply a source of fat.
Its main fatty acid is oleic acid, a monounsaturated fat, but EVOO also contains hundreds of minor compounds that are largely reduced or absent in more heavily refined oils.
Among the most interesting are olive phenolics such as:
- Oleocanthal
- Oleacein
- Hydroxytyrosol
- Tyrosol
- Ligstroside aglycone
- Oleuropein-related compounds
- Lignans such as pinoresinol
Researchers are investigating whether these compounds help explain some of the health associations seen with extra virgin olive oil.
That is where the laboratory and animal research becomes particularly interesting.
What is oleocanthal?
Oleocanthal is a naturally occurring phenolic compound found in extra virgin olive oil.
It is also one of the compounds associated with the peppery sensation you can feel at the back of your throat when tasting a fresh, phenolic-rich EVOO.
Scientists have become particularly interested in oleocanthal because of its interactions with inflammatory pathways and its activity in a wide range of experimental cancer models.
One laboratory study looked at both triple-negative breast-cancer cells and oestrogen-receptor-positive breast-cancer cells.
Oleocanthal reduced breast-cancer-cell proliferation and migration, while the researchers reported no comparable effect on the viability or proliferation of non-tumour breast cells.
The study suggested that one mechanism may involve a calcium channel called TRPC6, which is expressed at higher levels in the breast-cancer cells examined.
This is intriguing mechanistic research.
But it was performed in cells, not in women consuming olive oil.
Research: (-)-Oleocanthal inhibits proliferation and migration by modulating Ca2+ entry through TRPC6 in breast cancer cells
https://pubmed.ncbi.nlm.nih.gov/30321616/
What does the research say about triple-negative breast cancer?
Triple-negative breast cancer, or TNBC, is a particularly challenging form of breast cancer because the tumour cells lack three receptors commonly targeted by breast-cancer treatments.
Researchers have therefore been interested in whether components of the Mediterranean diet could influence biological pathways involved in TNBC.
A 2020 review examined evidence relating to olive oil, fish oil and their components in experimental TNBC models.
It highlighted studies suggesting that olive-oil phenolics and other Mediterranean-diet compounds can interact with signalling pathways involved in tumour growth and survival.
The researchers also noted that the evidence came mainly from cells and animals rather than clinical trials in patients.
Research: Do Olive and Fish Oils of the Mediterranean Diet Have a Role in Triple Negative Breast Cancer Prevention and Therapy?
https://pubmed.ncbi.nlm.nih.gov/33123546/
What has newer breast-cancer research found?
Research into combinations of olive-oil phenolics has continued.
A 2025 study investigated several individual EVOO phenolics and combinations of those compounds in models of invasive breast carcinoma.
Oleocanthal and ligstroside aglycone emerged as particularly active compounds.
When the researchers combined them, the mixture produced stronger effects against migration and invasion of triple-negative breast-cancer cells than either compound alone.
In mouse models, the oleocanthal–ligstroside aglycone combination also suppressed tumour progression and metastatic behaviour.
The study identified changes involving the SMYD2–EZH2–STAT3 signalling pathway as one possible mechanism.
This is sophisticated preclinical research and gives scientists a clearer understanding of how different olive phenolics may work together.
It does not, however, demonstrate that eating EVOO can prevent or treat breast cancer in people.
Research: Harnessing Nature’s Chemistry: Deciphering Olive Oil Phenolics for the Control of Invasive Breast Carcinoma
https://pmc.ncbi.nlm.nih.gov/articles/PMC12348913/
Where has The Governor EVOO been used in breast-cancer research?
This is where the research becomes particularly relevant to The Governor.
Several of the breast-cancer studies supplied by the University of Louisiana research group did not simply use a generic synthetic compound.
Researchers specifically extracted oleocanthal from The Governor EVOO from Corfu.
That distinction matters.
The experiments tested purified oleocanthal rather than asking people to consume The Governor, but the oil served as the original natural source of the compound used in the research.
The Governor and oleocanthal extraction
A 2019 PLOS ONE paper developed new methods for isolating EVOO phenolics.
The researchers used The Governor EVOO, batch 5-214000242017, and showed how to extract, purify, and then experimentally study oleocanthal.
The purified oleocanthal was subsequently tested in breast-cancer cell and mouse models.
The study reported anti-breast-cancer activity after oral administration in the animal model.
This is one of the clearest examples of The Governor’s direct involvement in breast-cancer research because the published paper identifies the oil itself.
Research: Novel liquid-liquid extraction and self-emulsion methods for simplified isolation of extra-virgin olive oil phenolics with emphasis on (-)-oleocanthal and its oral anti-breast cancer activity
https://pubmed.ncbi.nlm.nih.gov/30964898/
The Governor, oleocanthal and HER2-positive breast cancer
Another study investigated purified oleocanthal alongside lapatinib, a targeted medicine used in HER2-positive breast cancer.
The oleocanthal used in the experiments was extracted from The Governor EVOO.
In breast-cancer cells, the combination produced stronger anti-proliferative effects than either treatment alone.
In a mouse xenograft model, combined oleocanthal and lapatinib treatment also strongly suppressed tumour growth.
The researchers investigated signalling involving HER2, EGFR and c-MET and suggested that oleocanthal might help sensitise tumour cells to the targeted medicine.
This was an important preclinical finding.
But it is crucial to distinguish it from a clinical treatment study.
Women with breast cancer were not given The Governor EVOO or oleocanthal alongside lapatinib.
Research: (-)-Oleocanthal Combined with Lapatinib Treatment Synergized against HER-2 Positive Breast Cancer In Vitro and In Vivo
https://pubmed.ncbi.nlm.nih.gov/30781364/
Can oleocanthal influence breast-cancer recurrence?
One of the most interesting Governor-linked studies investigated what happened after a primary breast tumour had been surgically removed in mouse models.
Researchers studied both luminal and triple-negative breast cancer.
Once again, the published paper acknowledges that The Governor EVOO was supplied by the Dafnis family as the source of oleocanthal used in the experiments.
Oleocanthal treatment was associated with lower locoregional recurrence in the experimental models.
That finding is scientifically interesting because recurrence following treatment is an important area of breast-cancer research.
But these were mouse models.
It would be inappropriate to conclude from this research that consuming The Governor prevents breast-cancer recurrence in women.
What the study shows is that Governor-derived oleocanthal demonstrated sufficient biological activity in experimental models to justify further investigation.
Research: (-)-Oleocanthal Prevents Breast Cancer Locoregional Recurrence After Primary Tumor Surgical Excision and Neoadjuvant Targeted Therapy in Orthotopic Nude Mouse Models
https://pmc.ncbi.nlm.nih.gov/articles/PMC6562541/
The Governor and triple-negative breast cancer research
Researchers then worked on ways to make oleocanthal easier to administer orally.
One approach combined oleocanthal with xylitol in a solid formulation.
The published paper states that the oleocanthal used was extracted from The Governor EVOO from Corfu, and it acknowledges the Dafnis family for supplying the source oil.
In mouse models of triple-negative breast cancer, the formulation suppressed tumour development, growth and recurrence following surgical removal of the primary tumour.
Again, this is promising preclinical evidence rather than a human intervention trial.
Research: Novel Olive Oil Phenolic (-)-Oleocanthal (+)-Xylitol-Based Solid Dispersion Formulations with Potent Oral Anti-Breast Cancer Activities
https://pmc.ncbi.nlm.nih.gov/articles/PMC6765396/
What about the taste-masked oleocanthal study?
Another research group paper looked at developing an effervescent oleocanthal formulation because isolated oleocanthal has a particularly strong, irritating and bitter sensation.
The researchers again reported that they isolated oleocanthal from The Governor EVOO, batch 5-214000-242017.
The selected formulation was tested in mouse models of HER2-positive and hormone-receptor-positive breast cancer.
Researchers reported suppression of tumour growth and lower locoregional recurrence after primary tumour removal.
This was pharmaceutical-formulation research involving purified oleocanthal, not a dietary study involving people drinking olive oil.
Research: Optimization of Taste-Masked (-)-Oleocanthal Effervescent Formulation with Potent Breast Cancer Progression and Recurrence Suppressive Activities
https://pubmed.ncbi.nlm.nih.gov/31590382/
What have researchers found at the genetic level?
A later 2021 study took this research further by investigating the effect of an oleocanthal–xylitol formulation in more complex models of triple-negative breast cancer.
The researchers used both genetically engineered mice and patient-derived tumour xenografts.
Treatment suppressed tumour development and growth in these experimental models, while gene-expression analysis identified a number of biological pathways altered by oleocanthal treatment.
The work helps scientists understand how oleocanthal might influence tumour biology rather than simply observing that tumour growth changed.
This study builds on the same research programme as the earlier Governor-derived oleocanthal work.
However, the key point for consumers remains the same: these are preclinical models, not evidence that consuming high-oleocanthal EVOO treats triple-negative breast cancer.
Research: Comparative Gene Signature of (-)-Oleocanthal Formulation Treatments in Heterogeneous Triple Negative Breast Tumor Models: Oncological Therapeutic Target Insights
https://pubmed.ncbi.nlm.nih.gov/34069906/
So can olive oil help reduce breast-cancer risk?
Based on the evidence currently available, the answer is:
Possibly — particularly when extra virgin olive oil forms part of a Mediterranean-style diet, but we cannot say that olive oil itself has been proven to prevent breast cancer.
Several reasons are encouraging.
The PREDIMED randomised trial found a considerably lower incidence of breast cancer among women following a Mediterranean diet supplemented with EVOO.
A large 2022 meta-analysis found that higher olive-oil consumption was associated with a lower likelihood of breast cancer.
Earlier studies in Mediterranean populations also reported favourable associations.
At the same time, laboratory and animal research is building a detailed picture of how individual EVOO phenolics, particularly oleocanthal, may interact with mechanisms involved in tumour proliferation, migration, signalling and recurrence.
But those two areas of research should not be confused.
Human dietary studies tell us about olive oil consumption and breast-cancer risk.
Laboratory and animal studies tell us about the biological activity of particular olive compounds under experimental conditions.
Both are valuable, but they answer very different questions.
What else matters for breast-cancer risk?
Many factors influence breast-cancer risk, and some cannot be changed.
Modifiable lifestyle factors include maintaining a healthy body weight, being physically active, avoiding smoking, and limiting alcohol.
This last point is worth emphasising.
Alcohol is an established breast-cancer risk factor, so the traditional image of the Mediterranean diet should not be interpreted as a reason to start drinking wine for health.
For breast health, the most useful elements of Mediterranean eating are the foods themselves: vegetables, fruit, legumes, whole grains, nuts, fish and extra virgin olive oil.
The bottom line
There is no single food that can guarantee protection against breast cancer.
But the evidence around olive oil is genuinely interesting.
Human research suggests that greater olive-oil consumption and Mediterranean diets rich in EVOO may be associated with a lower breast-cancer risk.
The PREDIMED trial provides particularly encouraging randomised evidence, while larger observational analyses and meta-analyses broadly support further investigation.
At the same time, scientists are uncovering increasingly detailed mechanisms through which olive-oil phenolics such as oleocanthal may influence breast-cancer biology.
The Governor has an unusual place within this research.
Oleocanthal extracted directly from The Governor EVOO has been used in published laboratory and animal studies involving HER2-positive breast cancer, triple-negative breast cancer, tumour recurrence and experimental oleocanthal formulations.
That does not mean The Governor has been proven to prevent or treat breast cancer.
It means something more precise and scientifically more interesting:
Its naturally high oleocanthal content has made it a useful source oil for researchers investigating the biological activity of olive-oil phenolics in breast-cancer models.
For everyday health, the strongest message remains simple.
Choose a varied, Mediterranean-style way of eating, make extra virgin olive oil one of your principal dietary fats and enjoy it as part of good food rather than treating it as medicine.
Research discussed in this article
Mediterranean Diet and Invasive Breast Cancer Risk Among Women at High Cardiovascular Risk in the PREDIMED Trial
https://pubmed.ncbi.nlm.nih.gov/26365989/
https://pubmed.ncbi.nlm.nih.gov/26365989/
Olive oil intake and cancer risk: A systematic review and meta-analysis
https://pubmed.ncbi.nlm.nih.gov/35015763/
Consumption of Olive Oil and Specific Food Groups in Relation to Breast Cancer Risk in Greece
https://academic.oup.com/jnci/article-abstract/87/2/110/946863
Harnessing Nature’s Chemistry: Deciphering Olive Oil Phenolics for the Control of Invasive Breast Carcinoma
https://pmc.ncbi.nlm.nih.gov/articles/PMC12348913/
Do Olive and Fish Oils of the Mediterranean Diet Have a Role in Triple Negative Breast Cancer Prevention and Therapy?
https://pubmed.ncbi.nlm.nih.gov/33123546/
(-)-Oleocanthal inhibits proliferation and migration by modulating Ca2+ entry through TRPC6 in breast cancer cells
https://pubmed.ncbi.nlm.nih.gov/30321616/
Research involving oleocanthal sourced from The Governor EVOO
Novel liquid-liquid extraction and self-emulsion methods for simplified isolation of extra-virgin olive oil phenolics with emphasis on (-)-oleocanthal and its oral anti-breast cancer activity
https://pubmed.ncbi.nlm.nih.gov/30964898/
https://pubmed.ncbi.nlm.nih.gov/30964898/
(-)-Oleocanthal Combined with Lapatinib Treatment Synergized against HER-2 Positive Breast Cancer In Vitro and In Vivo
https://pubmed.ncbi.nlm.nih.gov/30781364/
(-)-Oleocanthal Prevents Breast Cancer Locoregional Recurrence After Primary Tumor Surgical Excision and Neoadjuvant Targeted Therapy in Orthotopic Nude Mouse Models
https://pmc.ncbi.nlm.nih.gov/articles/PMC6562541/
Novel Olive Oil Phenolic (-)-Oleocanthal (+)-Xylitol-Based Solid Dispersion Formulations with Potent Oral Anti-Breast Cancer Activities
https://pmc.ncbi.nlm.nih.gov/articles/PMC6765396/
Optimization of Taste-Masked (-)-Oleocanthal Effervescent Formulation with Potent Breast Cancer Progression and Recurrence Suppressive Activities
https://pubmed.ncbi.nlm.nih.gov/31590382/
Comparative Gene Signature of (-)-Oleocanthal Formulation Treatments in Heterogeneous Triple Negative Breast Tumor Models: Oncological Therapeutic Target Insights
https://pubmed.ncbi.nlm.nih.gov/34069906/
