A recent study in the Journal of Lipid Research suggests that soybean oil, which is widely used in the U.S., might directly contribute to obesity. The findings seem to relate to how our bodies metabolize one of its main components.
In the research, mice were given a diet high in soybean oil, and scientists observed how they processed linoleic acid, an omega-6 fatty acid prevalent in the oil. It turns out that linoleic acid breaks down into substances called oxylipins, and increased intake of linoleic acid raises oxylipin levels. This study established that certain oxylipins correlate with weight gain in mice.
“This could be an initial step in understanding why a diet rich in soybean oil may lead to weight gain in some individuals but not others,” explained Sonia Deol, a biomedical scientist and the study’s lead author.
The researchers asked whether reducing the conversion of linoleic acid to oxylipins would still lead the mice to become obese on a soybean oil diet. To explore this, they employed a genetically modified strain of mice that had alterations in a liver-regulating gene called P2-HNF4α. This genetic adjustment affects various metabolic pathways, including the reduction of particular enzymes responsible for converting linoleic acid to oxylipins. These enzymes are also found in humans, though their function can vary based on genetic factors, diet, and other variables.
After feeding both the genetically modified and normal mice a soybean oil-enriched diet, the results showed that the modified mice, surprisingly, exhibited healthier livers and gained significantly less weight compared to their normal counterparts.
Specific oxylipins created from linoleic acid and alpha-linolenic acid, another fat found in soybean oil, were noted to be linked with obesity in the typical mice, with higher levels in those that became obese.
The research implies that how the body processes linoleic acid may significantly influence how soybean oil contributes to fat accumulation. So, it might not just be the calories in the oil at play, but also what happens to those fatty acids once they enter our systems.
Although conducted in mice, the findings prompt a deeper look into whether high linoleic acid oils could lead to obesity through complex biochemical mechanisms beyond merely calorie intake. Soybean oil has emerged as the predominant cooking oil in American cuisine, appealing due to its affordability and neutral flavor, often found in packaged foods and fast-food items.
The researchers clarify that while their study doesn’t imply soybean oil directly causes obesity in humans, it sheds light on biochemical pathways that could clarify why a diet rich in this oil may induce weight gain in animal models. They do point out that the genetically altered mice differ from humans, also noting that these differences can limit how the results might apply to people.
