Study Links Oleic Acid to Stronger Immune Response in Cancer Patients
New research suggests that oleic acid, found in olive oil, may help restore immune defenses impaired by palmitic acid, potentially impacting the body’s resistance to cancer. The study found that patients with higher levels of oleic acid had stronger immune responses and better outcomes compared to those with higher levels of palmitic acid, which caused immune cells to function abnormally and lose their ability to kill tumor cells. Researchers caution that while the balance between dietary fats, particularly palmitic and oleic acids, may influence immune system control of cancer, more research is needed to fully understand the effects of individual fatty acids on human health.
New research provides fresh insight into how various fatty acids in the diet may impact the body’s resistance to cancer.
A study published in Signal Transduction and Targeted Therapy found that oleic acid — a fatty acid abundant in olive oil and other foods — may help restore immune defenses impaired by palmitic acid.
The researchers analyzed blood samples from cancer patients undergoing experimental immune-cell therapy and measured levels of palmitic and oleic acids.
They then compared those measurements with the patients’ responses to treatment.
Patients with higher levels of oleic acid tended to exhibit stronger immune responses and better outcomes, while those with higher levels of palmitic acid responded less effectively.
To understand the mechanism, scientists at the LKS Faculty of Medicine at the University of Hong Kong exposed a type of immune cell, gamma delta T cells (γδ‑T cells), to both fatty acids.
These white blood cells recognize stress signals on infected or cancerous cells and release toxic molecules to destroy them.
In laboratory experiments, γδ‑T cells exposed to palmitic acid lost a significant portion of their ability to kill tumor cells. They became inflamed, functioned abnormally, and eventually self-destructed.
When oleic acid was added, the cells regained their normal function: they survived, maintained energy metabolism, and recovered their capacity to destroy cancer cells.
Animal trials supported the findings. Mice fed diets rich in oleic acid mounted stronger immune responses against tumors, while those on high-palmitic diets showed weaker defenses.
The authors said the balance between dietary fats — particularly palmitic and oleic acids — may influence how effectively the immune system controls cancer.
However, they cautioned that the research is preliminary, involving a small number of patients and relying heavily on laboratory and mouse studies.
“We should bear in mind that we can make palmitic acid in our bodies. We don’t just get it from the diet and it actually exerts very important functions,” said Parveen Yaqoob, professor of Food and Nutritional Sciences at the University of Reading, who was not involved in the study.
“Palmitic acid and other fatty acids are essential components of the membranes in every cell of our body. Should we not have it, we would have a big problem. That is to say that focusing on one fatty acid is probably not a good thing,” she added.
Yaqoob noted that humans both produce and consume a wide range of fatty acids.
“Looking at the effects of individual fatty acids on cells, there is quite good evidence that in an artificial setup such as in vitro, if you add palmitic acid to cells there is almost no doubt that it will have bad effects compared with other fatty acids,” she said.
Still, she emphasized that such experiments cannot be directly translated into what happens inside the human body.
“When you eat you are digesting the fat. It does not reach the blood in the same way it is in the food. The body metabolizes it,” she explained. “Your liver will deal with it in a particular type of way.”
“When you look in a test tube, the effects of individual saturated fatty acids like palmitic acid are generally quite negative, and they’re generally more toxic than other types of fatty acids,” she added.
Oleic acid and palmitic acid differ structurally: oleic acid is monounsaturated, while palmitic acid is saturated.
Saturated fats have straight chains that pack tightly, making them solid at room temperature, like butter. Monounsaturated fats have a bend that keeps them more flexible, allowing them to remain liquid, like olive oil.
“The reason oleic acid is really interesting biologically is because compared with saturated fats, it seems to be much more neutral in effect,” Yaqoob said.
She added that oleic acid is less likely to cause the negative — or positive — effects seen with other fatty acids.
“It seems to be very neutral in the body or to have a slightly beneficial effect,” she said. “As an example, if you replace some of the saturated fat in your diet with olive oil, it has a beneficial effect on your blood cholesterol compared with saturated fat. And that’s fairly conclusive, fairly consistent, and uncontroversial in the literature.”
Some studies have also explored whether olive oil may have anti-inflammatory effects. However, Yaqoob noted that the findings remain mixed — partly because olive oil consumption is already a standard component of many diets.
She emphasized that research into the effects of fatty acids on human health is ongoing and often contentious.
“Here we are now focusing on one of the saturated fatty acids, palmitic acid. Still, that is not the only one; there are others which are highly significant, such as stearic acid,” she added.
Researchers are working to connect laboratory findings with real biological processes inside the body — an effort that spans multiple fields of biology.
“It is really important in order to understand possible mechanisms and understand the biological pathways by which these fatty acids actually work in normal function,” Yaqoob said.
“Then you can understand what goes wrong when you have too much of them, or an abnormal function. So yes, such research is important, but it needs to be looked at in the context of the bigger picture,” she concluded.
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