A new study has found that a common type of vegetable oil may contribute to weight gain due to the way it is processed within the body.
The study focused on soybean oil, which is widely used in processed foods, such as salad dressings and potato chips, although it is not typically used as a cooking base. Previous research has shown a link between its consumption and weight gain, but the reason for this effect was unclear.
In this regard, a team of scientists at the University of California, Riverside, clarified that it is not the oil itself that is the direct cause, but the way it is processed in the body that may lead to weight gain when consumed excessively.
Said Francis Saladik, a professor of cellular biology: "Soybean oil is not harmful in itself, but the amounts we consume stimulate pathways that our bodies are not evolved to handle".
Details of the experiment on mice
Researchers fed two groups of mice a diet rich in soybean oil:
Group one: Normal mice that underwent no genetic modification and gained significant weight during the experiment.
Group two: Genetically modified mice pre-designed to reduce the production of certain enzymes in the liver, responsible for converting linoleic acid (an essential fatty acid in the oil) into molecules called "oxylipins," which are linked to inflammation and fat accumulation when consuming linoleic acid in large quantities. These mice did not gain weight, and it was found that their liver was healthier, and the functions of their mitochondria (the power stations inside the cells) improved.
These results suggest that the internal metabolism of fats in the body, not just the oil itself or the calories alone, plays a key role in weight gain, and that genetic factors may determine the extent of the oil's impact on the body.
Said Sonia Deol, a biomedical scientist and the corresponding author of the study: "This may be the first step in understanding why some people gain weight more easily when following a diet rich in soybean oil".
The researchers note that the study does not prove that the oil necessarily causes obesity in humans, but it reveals a biochemical mechanism that helps explain why weight gain occurs when consuming a diet rich in this oil in mice, which may have implications for understanding the human response to saturated fats.
Although the study did not include human trials, the team hopes that the results will guide future research and improve nutritional policies.
