Colorectal cancer is the third most common cancer in the United States and the second leading cause of cancer-related mortality with 154,270 estimated new cases in 2025 and with 28,900 deaths among men and 24,000 deaths among women. Five-year disease-free survival rates are 91–18.9% for stages I–IV, respectively. It’s also worth noting that cases in people under age 55 are also on the rise. Additionally, colorectal cancer has a high rate of recurrence and development of resistance to existing therapies, ultimately leading to treatment failure.
Because of these statistics, new interventions to reduce risk of developing colorectal cancer, slowing its progression, and lower recurrence risk are in high demand. Previous research has linked adherence to a Mediterranean-style diet with decreased incidence of colorectal and other cancers. Specifically, polyphenol-rich extra virgin olive oil has been called out as a key food in this pattern of eating with compounds with promising disease-fighting properties.
A study by Tarun and colleagues that was published in Nutrients looked at the effect of oleocanthal on colorectal cancer progression using in vitro and mouse model designs. This study used The Governor, a high-phenolic Greek extra virgin olive oil as a source of oleocanthal and polyphenols. After screening the various olive oil-derived polyphenols’ effect on a panel of colorectal cancer cell lines in vitro, researchers selected oleocanthal as the focus for this study. This antioxidant compound, which is responsible for giving extra virgin olive oil its signature “zing,” has been associated with numerous anti-cancer benefits in studies, including protection against colorectal cancer progression and recurrence.
Study: The Anti-Tumor Effects of Oleocanthal on Colorectal Cancer
The researchers then conducted a trial in mice to assess the anti-tumor effects of oleocanthal and olive oil on colorectal cancer progression and recurrence.
15 mice were selected and randomized into 3 treatment groups:
- Two of the treatments were the experimental arms, and one was the control arm.
- The first experimental arm consisted of mice that received pure oleocanthal (10 mg/ kg) which was extracted from the Governor olive oil.
- The second treatment group included mice that received a polyphenol rich fraction of all polyphenols extracted from the Governor olive oil (PPRF).
- The control group consisted of mice that received olive oil that had all the polyphenols removed from it (de-phenolized olive oil).
The researchers induced colorectal tumors in all mice and allowed them to grow for 15 days, while the mice received one of the three oral treatments described above.
After 15 days, they performed surgeries and removed all tumors, but then continued the oral treatments and observations over a period of 40 additional days to assess recurrence.
Key Findings:
In the first phase of the study, after 15 days, they found that mice in the first two treatment groups, those who consumed pure oleocanthal or the PPRF had decreased tumor weight and volume compared to the mice that consumed the de-phenolized olive oil. The tumors in the mice that received one of the two oleocanthal treatments were around 72% smaller than the ones that received the olive oil devoid of polyphenols.
Moreover, in the second phase of the study, it was found that the same treatments also inhibited local and distant tumor recurrences.
While in the control group of mice that consumed de-phenolized olive oil all 5 mice developed recurrent tumors, only two of the five mice in each of the oleocanthal and PPRF treatment groups developing recurrences.
Additionally, in the oleocanthal and PPRF treatment groups, the first local recurrence was observed 16 days after recurrences started in the control group. The authors noted that considering that each 2.6 days of a mouse life is equivalent to one human year, the protective effects would be equivalent to 6.2 years of a human life.
Conclusion: Can Oleocanthal-Rich Olive Oil Prevent Colorectal Cancer Progression and Recurrence?
While these results are promising, it’s important to keep in mind that this is a study in cells and in a small number of lab animals. Also worth noting is that If the 10 mg/kg oleocanthal dose used in this study were translated to use in humans, assuming that a high-phenolic olive oil with about a 1 gram of oleocanthal per Liter dose were used, the volume required for the therapeutic effects of observed in this study would be about 700 mL (about 24 ounces) for a human weighing 70 kg, which is not realistic for regular use in food.
Nevertheless, mice and human metabolism is very different, and it is not a given that a human would require the same dose per KG to see the same effect. Studies looking at the effectiveness of lower doses of oleocanthal, and studies looking at both preventive and therapeutic interventions in humans would offer more insight into how much extra virgin olive oil could be meaningful in protecting against colorectal cancer.
In the meantime, keep enjoying high-phenolic olive oil as a regular part of the diet and incorporate other healthy habits that support cancer risk reduction, such as staying physically active, avoiding smoking, and maintaining a healthy weight.
