At the University of California, Riverside, groups of mice were fed a high-fat diet containing large amounts of soybean oil.
The result was clear:
Normal mice: gained significant weight.
Genetically modified mice: They gained almost no weight, despite eating the same diet.
The difference between the two groups was in a liver protein called HNF4α, which regulates hundreds of genes related to fat metabolism. The modified version of this protein seemed to change the way the body handles linoleic acid, the essential fatty acid found abundantly in soybean oil.
Inside the body, linoleic acid turns into compounds called oxylipins. When consumed in large quantities, levels of these molecules rise, which in the study have been linked to:
– Infections
– Fat accumulation
– Deteriorating liver health and weight gain
The genetically modified mice produced much lower amounts of these oxylipins, had healthier liver tissue and better mitochondrial activity, which may explain why they did not gain as much weight, despite the same regimen.
The study also showed that only oxylipin levels in the liver – and not in the blood – were linked to body weight, which means that standard blood tests may not detect these metabolic changes early.
Why isn’t everyone affected the same way?
Humans also have two forms of HNF4α, but the less common form usually appears in special cases such as:
– Chronic diseases
– Metabolic stress
– Alcoholic fatty liver
Combined with age, gender, medications, and genetic background, this variation may explain why some people are more likely to gain weight when drinking too much soybean oil than others.
The researchers also noted that genetically modified mice, when on a low-fat diet, may show elevated levels of some oxylipins without becoming obese, which means that the presence of these molecules alone is not enough, but rather interferes with other metabolic factors.
Scientists believe that the problem is not the “demonization” of the oil itself, but rather the large quantities that enter the modern diet, which stimulate pathways within the body that “our bodies did not evolve to deal with,” in the words of Francis Sladek.
The team hopes that these findings will help guide future nutrition research and policy, with a clear warning between the lines: just as it took the world decades to recognize the danger of tobacco, it should not be too late to review the place of soybean oil in our diet when consumed in excess. (sci tech daily)
