America’s most widely consumed cooking oil causes genetic changes in the brain

Summary: Soybean oil, the most consumed cooking oil in the US, has been linked to neurological and metabolic alterations in mice. Soybean oil-fed mice showed decreased levels of oxytocin in the hypothalamus.

Source: UCR

New UC Riverside research shows soybean oil not only leads to obesity and diabetes, but could also affect neurological conditions like autism, Alzheimer’s disease, anxiety, and depression.

Used for fast food frying, added to packaged foods, and fed to livestock, soybean oil is by far the most widely produced and consumed edible oil in the U.S., according to the U.S. Department of Agriculture. In all likelihood, it is not healthy for humans.

It certainly is not good for mice. The new study, published this month in the journal Endocrinology, compared mice fed three different diets high in fat: soybean oil, soybean oil modified to be low in linoleic acid, and coconut oil.

The same UCR research team found in 2015 that soybean oil induces obesity, diabetes, insulin resistance, and fatty liver in mice. Then in a 2017 study, the same group learned that if soybean oil is engineered to be low in linoleic acid, it induces less obesity and insulin resistance.

However, in the study released this month, researchers did not find any difference between the modified and unmodified soybean oil’s effects on the brain. Specifically, the scientists found pronounced effects of the oil on the hypothalamus, where a number of critical processes take place.

“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.

The team determined a number of genes in mice fed soybean oil were not functioning correctly. One such gene produces the “love” hormone, oxytocin. In soybean oil-fed mice, levels of oxytocin in the hypothalamus went down.

The research team discovered roughly 100 other genes also affected by the soybean oil diet. They believe this discovery could have ramifications not just for energy metabolism, but also for proper brain function and diseases such as autism or Parkinson’s disease. However, it is important to note there is no proof the oil causes these diseases.

Additionally, the team notes the findings only apply to soybean oil — not to other soy products or to other vegetable oils.

This shows a pot of cooking oil
Identifying the compounds responsible for the negative effects is an important area for the team’s future research. Image is in the public domain.

“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.”

A caveat for readers concerned about their most recent meal is that this study was conducted on mice, and mouse studies do not always translate to the same results in humans.

Also, this study utilized male mice. Because oxytocin is so important for maternal health and promotes mother-child bonding, similar studies need to be performed using female mice.

One additional note on this study — the research team has not yet isolated which chemicals in the oil are responsible for the changes they found in the hypothalamus. But they have ruled out two candidates. It is not linoleic acid, since the modified oil also produced genetic disruptions; nor is it stigmasterol, a cholesterol-like chemical found naturally in soybean oil.

Identifying the compounds responsible for the negative effects is an important area for the team’s future research.

“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.

“The dogma is that saturated fat is bad and unsaturated fat is good. Soybean oil is a polyunsaturated fat, but the idea that it’s good for you is just not proven,” Sladek said.

Indeed, coconut oil, which contains saturated fats, produced very few changes in the hypothalamic genes.

“If there’s one message I want people to take away, it’s this: reduce consumption of soybean oil,” Deol said about the most recent study.

About this neuroscience research article

Source:
UCR
Media Contacts:
Jules Bernstein – UCR
Image Source:
The image is in the public domain.

Original Research: Open access
“Dysregulation of Hypothalamic Gene Expression and the Oxytocinergic System by Soybean Oil Diets in Male Mice”. Margarita Curras-Collazo et al.
Endocrinology doi:10.1210/endocr/bqz044.

Abstract

Dysregulation of Hypothalamic Gene Expression and the Oxytocinergic System by Soybean Oil Diets in Male Mice

Soybean oil consumption has increased greatly in the past half-century and is linked to obesity and diabetes. To test the hypothesis that soybean oil diet alters hypothalamic gene expression in conjunction with metabolic phenotype, we performed RNA-seq analysis using male mice fed isocaloric, high-fat diets based on conventional soybean oil (high in linoleic acid, LA), a genetically modified, low-LA soybean oil (Plenish) and coconut oil (high in saturated fat, containing no LA). The two soybean oil diets had similar, albeit non-identical, effects on the hypothalamic transcriptome, whereas the coconut oil diet had a negligible effect compared to a low-fat control diet. Dysregulated genes were associated with inflammation, neuroendocrine, neurochemical, and insulin signaling. Oxt was the only gene with metabolic, inflammation and neurological relevance upregulated by both soybean oil diets compared to both control diets. Oxytocin immunoreactivity in the supraoptic and paraventricular nuclei of the hypothalamus was reduced while plasma oxytocin and hypothalamic Oxt were increased. These central and peripheral effects of soybean oil diets were correlated with glucose intolerance but not body weight. Alterations in hypothalamic Oxt and plasma oxytocin were not observed in coconut oil diet enriched in stigmasterol, a phytosterol found in 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.

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  1. I completly agree.. The only real fact in this article is Soybean oil = not too good for mice..

    This is the first time I come to this website and I lost trust in it..

  2. I noticed that they don’t even differentiate between naturally extracted “expeller-pressed” oil and your average oil, which is always chemically extracted and ALWAYS very unhealthy and disease-causing! This is what we get when you have scientists doing food studies who don’t understand the food industry and what they are dealing with. They get lazy and sloppy with their research, assuming it’s all the same and so they clump it all together , package it up and stick a bow on it so they can get their bullshit papers published and get their name out there in the “scientific” community. lol
    What a sham.

  3. This is not a good study. The (GMO) soybean oil should be compared with organic soybean oil, GMO canola, organic canola, GMO corn, organic corn, and organic coconut oil. Comparing it with coconut oil, there are many dissimilar factors – glyphosate levels, saturated fats, BT toxin. The author of this article also made the wrong interpretation that all other oils are ok to eat – that’s not what the study says – that coconut oil is ok to eat. All other oils were not studied. I give this author an F for effort.

  4. Soy is bad and is Estrogenic, goitrogenic, and anti-nutritive! It is ONLY safe after fermentation as in tempeh, miso, natto, and Brewed soy sauce. Otherwise the more you eat the more Malnourished you get! It blocks absorbption of Iron, Magnesium, Copper, Zinc and B-12! You can be misdiagnosed with early Alzheimer’s with simply a B-12 deficiency which causes memory loss, depression and incontinence to name a few! And low iron alone can cause infertility and mimic Hypothyroidism!
    Look up the many symptoms deficiencies of these nutrients cause!! And you WILL decide to eliminate soy and it’s rancid oil.
    Smp

  5. Tofu, edamame, etc are not soybean oil products…they’re soy products. Oil is not a whole food, but the soy products they mentioned are. I’m surprised they forgot to mention tempeh. lol I’m not much of a soy fan, but I like tempeh and edamame in small amounts as well as a bite or two of hubby’s tofu.

  6. The title of article is incomplete. Many people will only read the title and possibly the first & second paragraph. Most people will not get to the caveat of the article. This article presentation is exactly how fake news gets started.

  7. Then why make a big fuss over the matter if you are telling everyone not to get rid of their soybean oil products? Quit contradicting what you are speaking of. I don’t eat soy products anyways. This article is total bullshit. Bye.

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