A fatty acid commonly found in olive oil and other plant oils has been shown to stimulate the body’s creation of new fat cells, potentially increasing fat storage and leading to weight gain over time. Previously, this weight gain was thought to result mainly from the high calorie content of foods containing the acid.
How Excess Olive Oil May Tip the Balance Toward Fat Cell Growth
Researchers from the University of Oklahoma, along with teams from Yale and NYU, discovered that oleic acid—a monounsaturated fat known for its heart and cholesterol benefits and a key part of the Mediterranean diet—can, when consumed in excess, boost levels of a signaling protein called AKT2 and suppress the activity of a regulatory protein known as LXR. This imbalance promotes the growth of precursor cells that develop into fat cells.
“We know that the types of dietary fats people consume have shifted during the obesity epidemic,” said Michael Rudolph, assistant professor of biochemistry and physiology at the University of Oklahoma College of Medicine. “Our goal was to understand whether obesity results simply from overeating fatty foods, or if the specific makeup of fatty acids in those oils plays a role. Are certain fat molecules triggering cellular responses?”
Oleic acid—an omega-9 fatty acid and the main fat in olive oil—is also present in canola, sunflower, avocado, and peanut oils, as well as many animal fats. Food manufacturers now widely use high-oleic versions in processed and fast foods because these oils prolong shelf life.
Oleic Acid Uniquely Triggers Fat Cell Formation in Mice and Humans
In the study, mice were fed diets high in various fats, including lard, coconut oil, and milk. Among all the fatty acids tested, only oleic acid activated the body’s fat cell formation pathway. This led to an increase in adipocyte precursor cells (APCs) and sped up their development into mature fat cells. Lab-grown human APCs showed similar effects.
Normally, this process—called adipogenesis—is a healthy, regulated mechanism. When fat cells reach capacity, they signal dormant APCs to convert into new fat cells, providing extra storage and preventing fat from spilling into the bloodstream, liver, or muscles, where it can cause serious health problems.
However, the researchers found that excessive oleic acid disrupted this balance, triggering the production and activation of APCs even when the body didn’t need them.
“You can think of fat cells like an army,” said Rudolph. When the body takes in oleic acid, it temporarily increases the number of “fat cell soldiers,” boosting its ability to store extra nutrients from food. But if those nutrients continue to exceed what the fat cells can hold, it can lead to obesity, which in turn raises the risk of conditions like heart disease and diabetes if left unmanaged.
Oleic Acid May Promote Fat Storage — Long-Term Effects Unknow
Research has shown that fat cells have an epigenetic “memory,” meaning they don’t disappear with weight loss — they just shrink and can linger for years. This makes shedding pounds more difficult and regaining them easier. By increasing both the number and responsiveness of fat cells, oleic acid may set the stage for fat tissue to store more fat over time.
However, the study has some notable limitations. For one, the researchers conducted the study only on mice and isolated human cells. They couldn’t directly manipulate APCs, leaving it unclear how other biological factors might play a role. Also, it’s not certain whether an increase in APCs that become fat cells directly causes obesity. The study doesn’t explore long-term effects on blood sugar, insulin, or inflammation. So while we better understand how fat cells form, it’s still unknown whether making more of them is ultimately beneficial or harmful.
And importantly, context matters. Researchers have extensively studied oleic acid in Mediterranean diets, where people use olive oil in moderation, and have linked it to positive health outcomes, including lower cholesterol and a reduced risk of heart disease, cancer, and other illnesses.
“The key takeaway is moderation and diversity in fat sources,” Rudolph explained. “Moderate amounts of oleic acid appear to offer health benefits, but excessive and prolonged intake could be harmful. For individuals at risk of heart disease, consuming high levels of oleic acid might not be advisable.”
Read the original article on: New Atlas
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