Olive oil. Credit: Tabibak / Wikimedia Commons / CC BY-SA 4.0
Olive oil may do more than flavor food. It could also strengthen the body’s natural defenses against cancer. A new study led by Yanmei Zhang, published in Nature, shows that a healthy fatty acid found in olive oil and nuts can enhance the body’s cancer-fighting power by improving how certain immune cells attack tumors.
The research focuses on γδ T cells, rare but highly effective immune cells capable of killing off tumor cells. These have been studied for years in cancer immunotherapy, but the treatment results in patients have been inconsistent. Zhang’s team explored whether dietary fats could be one reason why.
Higher olive oil fat levels linked to better therapy response through cancer-fighting effects
The team analyzed blood samples from seven liver cancer patients undergoing γδ T cell therapy. They found that patients who responded well to treatment had higher levels of oleic acid—the primary fatty acid in olive oil and nuts —and lower levels of palmitic acid, a saturated fat commonly found in palm oil and processed foods.
The ratio between the two fats correlated with longer survival, suggesting that the type of dietary fat might influence cancer treatment outcomes. This echoes the ancient Mediterranean diet, rooted in Greek culture, in which olive oil has long been a central source of health and vitality.
In lab tests, γδ T cells exposed to palmitic acid lost much of their ability to kill off cancer cells. They produced fewer tumor-killing proteins and showed weakened energy production. In contrast, cells treated with oleic acid became more active and efficient in destroying cancer cells. When both fats were combined, oleic acid reversed much of the damage caused by palmitic acid.
Further analysis revealed that palmitic acid caused a form of inflammatory cell death called pyroptosis. It was driven by excess secretion of interferon-gamma, a key immune signaling molecule.
This set off a chain reaction through the STAT1–IRF1–iNOS pathway, damaging the γδ T cells and limiting their tumor-fighting capacity. Oleic acid prevented this destructive process, protecting the cells from self-destruction.
Animal studies confirm protective, cancer-fighting properties of olive oil
To test the findings in living organisms, researchers fed mice different high-fat diets—one based on palm oil, another on olive oil, and a third combining both.
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Mice given human γδ T cells treated with palmitic acid and fed palm oil diets developed faster-growing tumors. However, those given oleic-acid-treated cells and fed olive oil diets exhibited slower tumor growth and longer survival.
When both fats were present, the effects of olive oil appeared to counterbalance the damage caused by palm oil.
Blocking harmful pathways restores immune power
The study also identified potential therapeutic strategies. Blocking CPT1A, an enzyme that transports fats into cell mitochondria, restored γδ T cell function after palmitic acid exposure.
Another compound, dimethyl fumarate, which prevents pyroptosis, reduced cell death and revived antitumor activity. These findings highlight how targeting metabolism and cell-death pathways could make immunotherapies more effective.
While the study involved a small group of patients, it adds to growing evidence that diet plays a crucial role in immune health. Saturated fats such as palmitic acid appear to weaken the body’s defense, while monounsaturated fats such as oleic acid—the primary fat in olive oil—enhance it. This reinforces a long-standing Greek philosophy of balance and moderation in food, whereby olive oil has symbolized both nourishment and longevity for over three thousand years.
Greek roots of olive oil’s legacy
The finding adds scientific weight to what ancient Greeks long believed about the healing and “life-giving” power of olive oil.
The connection between olive oil and Greece goes back to ancient times. Archaeological discoveries on Crete show that olive cultivation began as early as 3500 BC, making Greece one of the earliest centers of olive domestication.
Ancient Greeks called olive oil “liquid gold,” using it not only in cooking but also in medicine, athletics, and religious rituals. Hippocrates, often called the father of medicine, recommended olive oil for treating wounds and illnesses, a practice that mirrors modern science’s recognition of its healing potential.
Today, Zhang’s research brings that ancient belief into the laboratory, showing that olive oil’s key compound, oleic acid, truly supports the body’s defense systems—from heart health to its newfound role in cancer immunity.
Olive oil and implications for future cancer therapies
Zhang’s team suggests that including more olive oil and other sources of healthy fats in the diet could support immune-based cancer treatments. The findings also suggest new ways for researchers and clinicians to integrate dietary approaches with immunotherapy.
Just as the ancient Greeks saw the olive tree as a symbol of life and protection, modern science suggests that olive oil may safeguard the human body—not just in legend but in medicine.
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