KEY POINTS

  • Per recent estimates, 62 million tons of soybean oil were produced worldwide
  • Its high smoke point makes it one of the best cooking oil for deep frying, baking, and roasting
  • A new study points out that it causes genetic changes in the brain

Soybean oil has been increasingly used over the past few decades in the U.S. and other western countries, particularly for deep frying. It is used in several methods of cooking, such as baking and roasting. Its relatively high smoke point makes it a great option for deep frying and other high-heat cooking methods.

However, a new study, conducted by the researchers at UC Riverside, has reported that soybean oil not only causes diabetes and obesity but also makes genetic changes to the brain, which can lead to neurological conditions including anxiety, autism, Alzheimer’s and depression.

The researchers, who wanted to understand how the oil produces such negative consequences, investigated its impact on the gene expressions in the hypothalamus region of the brain, which regulates metabolism and several other processes.

The study was conducted using mice models. While one group of mice was given a diet high in normal soybean oil, the other one was given a diet high in soybean that lacked linoleic acid, and the third one was fed on a coconut oil-rich diet.

Their findings suggested that the soybean oil modified the expression of around a hundred different genes present in the hypothalamus region, affecting several processes including inflammation, neurological diseases and metabolism. The two soybean oil diets were found to have similar effects on the hypothalamic transcriptome compared to the coconut oil diet.

The altered genes include those linked to schizophrenia, depression and Alzheimer's disease. The most affected gene was the one that codes for the hormone oxytocin, which promotes social bonding and feelings of euphoria. Disruptions to the function of this gene were associated with depression and autism. The oxytocin gene was found to be affected in both the groups that consumed soybean oil and not the one that was fed a coconut oil-rich diet.

The researchers doubted whether a compound called stigmasterol found in soybean oil could be the main cause for the changes,  and conducted the study on mice fed with a coconut oil-rich diet containing high amounts of stigmasterol. But they found no alterations in the genes from this compound. Future research is needed to find the molecule responsible for these genetic changes. The researchers have urged people to reduce the consumption of soybean oil.

“We postulate that neither stigmasterol nor LA is responsible for effects of soybean oil diets on oxytocin and that Oxt mRNA levels could be associated with the diabetic state. Given its ubiquitous presence in the American diet, the observed effects of soybean oil on hypothalamic gene expression could have important public health ramifications,” the study authors wrote.

fat-592336_1920 Soybean Oil Photo: Hans, Pixabay