Study Finds Soybean Oil Causes Obesity and Diabetes in Mice

There is scary news out of America, and it has nothing to do with what’s happening with their politics. Let’s jump right into the topic: New research shows that soybean oil not only leads to obesity and diabetes, but also may adversely impact our brains leading to higher probability of autism, Alzheimer’s disease, anxiety and depression. Phew, that’s a truck load of health complications all due to one little bottle of oil.

Should we be worried? Isn’t soybean oil a rarity in our diets? How many of us consume this stuff, eh? Well, while it might be true that most of us do not use this as a cooking medium at home, soybean oil is, hold your breath, the most used oil base in North America. It’s used in fast food frying, packaged food products, and fed to livestock. So, one way of the other, we are getting a dose of this dangerous oil without even being aware of it. Who knew that we would be indirectly consuming soybean oil by ordering a ‘harmless’ bag of fries?

The study results were published in the journal Endocrinology. A team of scientists at University of California Riverside (URC), set out to study the effects of soybean oil by putting mice on three different types of diet: Soybean oil, modified Soybean oil (lower in linoleic acid) and coconut oil.

There is a side story here on why a diet of modified soybean oil had to be part of the study. The research team behind the latest study had originally found, back in 2015, that soybean oil induced obesity, diabetes, insulin resistance and fatty liver syndrome in mice. The findings proved be quite controversial at the time. A follow up study was undertaken in 2017, this time with lower levels of linoleic acid in the soybean (hence modified). The 2017 study found that the lesser the linoleic acid in the oil, the lesser the chances of obesity and diabetes.

The ‘pass’ status gave ‘modified’ soybean relief from scrutiny for a few years. But unfortunately for the manufacturers of this oil, and lucky for us, the URC research team retested everything for a third time. And the results are not good for the mice, and potentially dangerous of the humans.

Mice fed on soybean oil, including the modified version, were found to affect the hypothalamus region of the brain profoundly. "The hypothalamus regulates body weight via your metabolism, maintains body temperature, is critical for reproduction and physical growth as well as your response to stress," said Margarita Curras-Collazo, a UCR associate professor of neuroscience and lead author on the study.

Along with the harm done to the brain functions, it was also noticed that the behaviour of almost a hundred genes in the mice were impacted as a result of the soybean oil. The team is yet to isolate the specific chemicals contained in the oil that is causing these symptoms, but they have ruled out linoleic acid as lower levels of it made no difference in the outcome.

There is yet no correlation established between humans and consumption of soybean oil. That’s because there has been no human trial undertaken. And what happened to mice may not translate easily into humans. But maybe it will. When there is evidence of this nature already, it’s customary to raise the caution flags. Let’s also remember that scores of other research, validated by medical science later, also began on mice. 

The team is not stopping here. They would continue to hunt for the chemical(s) that is in soya oil that is causing these harmful effects. "This could help design healthier dietary oils in the future," said Poonamjot Deol, an assistant project scientist in Sladek's laboratory and first author on the study. "If there's one message I want people to take away, it's this: reduce consumption of soybean oil," she added.

The researchers were also keen to separate the other beneficial soya products from the soybean oil. "Do not throw out your tofu, soymilk, edamame, or soy sauce," said Frances Sladek, a UCR toxicologist and professor of cell biology. "Many soy products only contain small amounts of the oil, and large amounts of healthful compounds such as essential fatty acids and proteins."

As concerned consumers, we can educate ourselves by reading the labels carefully to determine if they contain soybean oil and decide to use it or not. Sadly, not every place that the soybean oil is present may announce its presence. It’s even used in the making of printing ink, according to some reports! So, as the road sign says: Proceed with Caution.

And to end on a good note: The third oil tested in the research study, coconut, was found to cause the least changes in the mice brain.