This Affordable Oil Disrupts Your Body’s Signals

For decades, fats were classified according to simplistic criteria, opposing the bad saturated ones to the virtuous unsaturated ones. This divide has shaped our eating habits, valuing vegetable oils without real examination of their long-term effects. Soybean oil, which has become omnipresent in processed products, rarely escapes analysis. However, behind its apparent nutritional neutrality, it could well have a profound influence on the regulatory mechanisms of the human body.

​​From soy to excess weight: a century of industrialization

A hundred years ago, soybean oil made up just 2 percent of the average calorie intake in the United States. Today, it reaches almost 10%. This dazzling growth is not insignificant. The industrial success of soy has accompanied the rise of ultra-processed foods, marked by massive intakes of polyunsaturated fatty acids, particularly linoleic acid.

If the latter is an essential fatty acid, necessary in small quantities, its overconsumption proves problematic. According to Journal of Lipid Research, linoleic metabolism in the liver produces compounds called oxylipins, which are associated with chronic inflammation and body fat accumulation. These metabolites only existed in trace amounts in the traditional diet, but their presence is exploding in the body today, particularly when soybean oil is consumed in excess.

What soybean oil reveals once in the liver

Experiments carried out on mice have revealed the insidious mechanisms at work. Fed a diet rich in soybean oil, the mice showed significant weight gain, as well as impaired liver function. Even more surprising, when a group of genetically modified rodents were put on the same diet, their metabolism reacted differently. These animals were able to consume the same amounts of fat without becoming obese or developing fatty liver disease.

The study conducted by Sonia Deol and relayed by UC Riverside News sheds new light. The differences between the two groups cannot be explained by the amount of fat. Rather, they depend on how it is processed by the body. Resistant mice had fewer oxylipins in their livers. They also showed better mitochondrial activity. In addition, certain enzymes were less active in transforming linoleic acid into inflammatory compounds.

The results, relayed by The Independent, go even further. The researchers found that only oxylipins found in the liver, not in the blood, were correlated with increased body weight. Essential information, which could explain why certain medical tests fail to detect diet-related disorders early.

Towards a new look at vegetable fats?

Vegetable oils have long enjoyed a health image. Cholesterol-free, of plant origin, rich in omega-6: all the arguments seemed in their favor. But current research encourages us to qualify this discourse. The problem may not be with soybean oil itself, but with the way our bodies process some of its components when they are ingested in industrial quantities.

Frances Sladek, professor of cell biology at UC Riverside, points out that our bodies have not evolved to cope with such concentrations. In his words, “it is not the oil that is bad, but the volume in which we consume it.” A parallel is even drawn by the research team. It took a century to formally link tobacco to cancer and impose warnings on packages. Scientists hope it won't take so long for the effects of soybean oil to be recognized.

To date, no clinical studies have yet been conducted in humans. However, the results obtained on mice, combined with the parallel progression of obesity and the consumption of oils rich in linoleic acid, justify particular attention. Especially since other common oils, such as corn or sunflower, have similar profiles.

Researchers continue to study the effects of oxylipins on our metabolism. Their goal remains simple but essential. They want to know how our eating habits influence, without noise, our internal balances. This link between nutrition and biological regulation is increasingly becoming a major area of ​​research.