America’s favourite cooking oil linked to obesity, scientists find

It’s the cooking oil Americans reach for every single day, often without a second thought. In fact, it is a staple in processed foods. A cooking oil commonly consumed in the United States could be fuelling the obesity crisis.

A recent experiment conducted at UC Riverside found that America’s favourite cooking oil is linked to obesity. The findings of the research are published in the Journal of Lipid Research.

Soybean oil linked to obesity

The researchers found that soybean oil, which is widely consumed by Americans, significantly contributes to obesity, at least in mice. The researchers also explored the metabolic pathway behind weight gain in mice.

During the experiment, the researchers found that most mice on a high-fat diet rich in soybean oil gained significant weight. However, this oil had no impact on genetically engineered mice. Instead, they produced a slightly different form of a liver protein that influences hundreds of genes linked to fat metabolism. This protein also changes how the body processes linoleic acid, a major component of soybean oil.

“This may be the first step toward understanding why some people gain weight more easily than others on a diet high in soybean oil,” corresponding author Sonia Deol, a UCR biomedical scientist, said.

The researchers noted that both versions of the liver protein HNF4α exist in humans; however, the alternative form is produced only under certain conditions, such as chronic illness or metabolic stress from fasting or alcoholic fatty liver. This variation, along with differences in age, sex, medications, and genetics, may help explain why some people gain weight, and others don’t, while consuming soybean oil.

This new experiment builds on previous work by UCR researchers linking soybean oil to weight gain. “We’ve known since our 2015 study that soybean oil is more obesogenic than coconut oil. But now we have the clearest evidence yet that it’s not the oil itself, or even linoleic acid. It’s what the fat turns into inside the body,” Frances Sladek, a UCR professor of cell biology, said.

The linoleic acid in soybean oil is converted into molecules called oxylipins. Excessive consumption leads to increased amounts of oxylipins, which are linked with inflammation and fat accumulation.

Is soybean oil the villain?

Soybean oil is widely consumed in the US. In fact, a 2011 study published in the American Journal of Clinical Nutrition found that there has been a five-fold increase in soybean oil consumption in the past century, from about 2% of total calories to nearly 10%.

Though soybeans are excellent sources of plant-based protein and their oil contains no cholesterol, excessive consumption of linoleic acid may cause more harm than good. As soybean oil is a staple in ultra-processed foods, it may be fuelling chronic metabolic conditions.

The researchers also found that despite the lack of cholesterol in soybean oil, its consumption is still associated with higher cholesterol levels in mice.

“Soybean oil isn’t inherently evil. But the quantities in which we consume it are triggering pathways our bodies didn’t evolve to handle,” Sladek said.

“It took 100 years from the first observed link between chewing tobacco and cancer to get warning labels on cigarettes. We hope it won’t take that long for society to recognise the link between excessive soybean oil consumption and negative health effects,” Sladek added.

Note: The information provided in this article is for educational purposes only and is not intended as medical advice. Always consult a qualified healthcare professional before starting any new medication or treatment, or before changing your diet or supplement regimen.