A key food in salad dressings, toast or cooking base, this oil could accelerate the growth of certain tumors. The researchers behind this discovery did not expect it.
It has been presented for years as the healthiest fat there is, but a new study has shaken up this certainty. What is in the crosshairs of scientists is oleic acid, the main active molecule of this health oil unanimously recommended by nutritionists.
Long recognized for its benefits for the heart, oleic acid is at the center of a study published in Cancer Discovery. According to this research, this compound can speed up the growth of certain tumors, while other fats slow it down by half. To achieve this surprising result, the researchers designed 12 different diets, all as high in calories as each other, but with different sources of fat. They tested them on mice genetically predisposed to developing pancreatic cancer. One of the most aggressive cancers.
Result: Mice developed tumors more quickly when fed a diet rich in oleic acid. Oleic acid is a fatty acid present in particular in olive oil, the famous oil perceived as excellent for health from all points of view. “It’s really the type of fat you eat that matters, not just the total amount”explains Christian Felipe Ruiz, chief researcher of the study. It is also found in sunflower oil, peanuts and lard. “Depending on the type of fat, the effects can be radically opposite. Some promote cancer, others really slow it down.”
What fats can slow down cancer? Omega-3s, like those found in fish oil. “When we fed mice diets enriched with fish oil, we saw a 50% reduction in disease compared to mice fed a standard high-fat diet.” According to researchers, the effect of fats on cancer cells comes from their oxidation. Omega-3 fats are easily oxidized, which makes cancer cells vulnerable. Oleic acid resists oxidation and thus protects tumors from their natural destruction.
Be careful, however: the study was carried out on mice, not on humans. The results do not mean that you should ban olive oil from your plate. Its benefits for the heart also remain well established. On the other hand, they invite you to diversify your sources of fat: more fatty fish, more omega-3, for a balance that olive oil alone may not be enough to guarantee. Don’t forget the importance of storing your oil in the right place. Pancreatic cancer is one of the deadliest cancers. In France, nearly 16,000 new cases are diagnosed each year. The 5-year survival rate is only 11% of patients.
