Olive oil may lower the risk of developing breast cancer, finds study

Breast cancer is the most commonly diagnosed cancer among women globally. In 2022 alone, around 2.3 million women were diagnosed with the disease, and approximately 670,000 died. What’s more concerning is that the World Health Organization (WHO) has also projected that, if current trends continue, both incidence and mortality will rise by about 40% by 2050 in many regions, including those with limited health infrastructure.

However, a fresh wave of hope is stirring in the world of cancer prevention during Breast Cancer Awareness Month . A study suggests that olive oil may help reduce the risk of developing breast cancer.


Olive oil and breast cancer : What the study says

A paper from Italy, published in 2024 in the European Journal of Cancer, examined data from 11,442 women who were part of the Moli-sani cohort. The researchers tracked these women for about 13 years, recording their diets and the incidence of breast cancer. Alongside this cohort analysis, the team also carried out a systematic review of earlier observational studies to explore the consistency of the association.

What’s the key finding? The study found that women with higher olive oil consumption had a reduced risk of breast cancer. More specifically, for every extra tablespoon (≈ 10 g) of olive oil consumed daily, there was a proportional reduction in breast cancer risk . The “very linear” association held even after adjusting for many other factors, which means each increment (for example, an extra tablespoon) of olive oil was linked with a further drop in risk. Notably, the protective effect appeared especially strong against certain types of cancer – those lacking estrogen or progesterone receptors (estrogen-receptor–negative – ER-negative, progesterone-receptor–negative– PR-negative), where hormone-driven pathways are less dominant.



Meta-analyses and earlier evidence

This particular study lines up with previous evidence. A meta-analysis pooling 14 study arms found that people with high olive oil intake had a 33% lower risk of breast cancer compared with low-intake groups (relative risk ~0.67). This protective relationship held both in Mediterranean and non-Mediterranean populations.

Besides, one of the most often-cited trials is part of PREDIMED (a Spanish long-term nutrition trial). In that analysis, older women (ages 60–80) who followed a Mediterranean diet supplemented with extra virgin olive oil (EVOO) had a 62–68% lower risk of breast cancer compared to women assigned to a low-fat diet group. However, as the researchers caution, the number of breast cancer cases in that sub-analysis was small (35 cases) and breast cancer was not the primary focus of that trial.

On the other hand, evidence is less clear in non-Mediterranean populations. For example, a prospective study in US women (from the Nurses’ Health Studies) did not find a significant association between higher olive oil intake and breast cancer risk — possibly because average consumption there is much lower.



How could olive oil help?

Bioactive phenolic compounds: Extra virgin olive oil (EVOO) contains polyphenols like oleocanthal, hydroxytyrosol, and oleuropein. Laboratory studies show that oleocanthal can damage lysosomes in cancer cells and trigger cell death, while sparing normal cells.

Anti-inflammatory and antioxidant action: Chronic inflammation and oxidative stress are underlying drivers of cancer development. Olive oil’s antioxidant compounds may reduce DNA damage, suppress certain pro-growth signals, and curb inflammatory pathways.

Modulation of gene expression, apoptosis, and cell proliferation: Animal and cell models suggest that olive oil diets can reduce tumor incidence, delay onset, and lead to less aggressive cancers compared to diets rich in linoleic acid or seed oils. In experimental mammary tumor models, high-olive-oil diets resulted in fewer, smaller, and less malignant tumors.

Hormonal and non-hormonal pathways: Since some breast cancers are hormone-driven (e.g., estrogen receptor positive), the beneficial effect of olive oil might vary by cancer subtype. In the Italian study, the stronger link to hormone-receptor negative tumors hints that olive oil may act via non-hormonal pathways.


Considerations to keep in mind

Despite its substantial promise, olive oil is not a standalone “cure” or prevention guarantee. It’s one component of a healthy diet, not a magical shield. It seems most effective when used within a balanced, plant-rich, Mediterranean-type diet. Additionally, quantity and quality matter. Effects appear stronger in populations with moderate to high olive oil intake (e.g., Mediterranean countries). The type of olive oil – unrefined, extra virgin with bioactive compounds – may make a difference.

Besides, population and context bear heavily. In US studies where olive oil intake is low, benefits were not clear. Also, the Italian study focused on women in a certain age bracket and setting; findings may not apply identically across all demographics. So, further research is also needed, as long-term randomized controlled trials might better clarify causality and dose. Studies should also explore mechanisms, interactions with other nutrients, and cancer subtypes.

Furthermore, there’s no good in ignoring established cancer-prevention strategies. Maintaining a healthy weight, being physically active, limiting alcohol use, avoiding tobacco, and routine screenings remain the cornerstones of breast cancer risk reduction .