New research from UC Riverside shows that soybean oil not only promotes obesity and diabetes, but could also affect neurological conditions such as autism, Alzheimer’s disease, anxiety, and depression.
Soybean oil, which is added to packaged foods, used to fry fast food and employed as livestock feed, is by far the most widely produced and consumed dietary oil in the US, according to the US Department of Agriculture. It’s very likely to be unhealthy for humans.
At least, it certainly is for mice. A new study, published in the journal Endocrinology, compared mice that were fed three different high-fat diets: soybean oil, modified soybean oil low in linoleic acid, and coconut oil.
The same UCR research team found in 2015 that soybean oil promotes obesity, diabetes, insulin resistance, and fatty liver in mice. Later, in a 2017 study, the same group found that if soybean oil is modified to become low in linoleic acid, it promotes obesity and insulin resistance less strongly.
However, in the study published now, the researchers found no difference between the effects of modified and unmodified soybean oil on the brain. Specifically, the scientists found marked effects of soybean oil on the hypothalamus, where a number of critical processes take place.
“The hypothalamus regulates body weight through its metabolism; it maintains body temperature, and is critical to reproduction and growth, as well as to stress response,” Margarita Curras-Collazo, associate professor of neuroscience at UCR and lead author of the study said.
The team determined that several genes in mice fed with soybean oil weren’t working properly. One of those genes produces the “love” hormone, oxytocin. In mice fed with soybean oil, oxytocin levels in the hypothalamus dropped.
The research team discovered around 100 other genes also affected by the soybean oil diet. They believe that this discovery could have implications not only in relation to energy metabolism, but also in terms of the proper functioning of the brain and ailments such as autism or Parkinson’s disease. However, it’s important to note that there’s no evidence that soybean oil triggers these diseases.
Effects of vegetable oils
Furthermore, the team noted that the findings only apply to soybean oil, and not to other soy products or other vegetable oils.
“Don’t throw away your tofu, soy milk, edamame, or soy sauce,” Frances Sladek, a UCR toxicologist and cell biology professor said. “Many soy products contain only small amounts of oil, and large amounts of healthy compounds such as essential fatty acids and protein.”
One caveat to readers concerned about their latest meal is that this study was conducted on mice, and mouse studies don’t always translate into the same results for humans.
Moreover, this study used male mice. Because oxytocin is so important to maternal health and promotes the mother-child bond, similar studies need to be conducted on female mice.
An additional note about 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 isn’t linoleic acid, since the modified oil also produced genetic alterations; nor is it stigmasterol, a cholesterol-like chemical that occurs 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 produce healthier dietary oils in the future,” Poonamjot Deol, a project assistant scientist in Sladek’s lab and first author of the study added.
“The common belief is that saturated fats are bad and unsaturated fats are good. Soybean oil is polyunsaturated fat, but the idea that it’s good for health isn’t proven yet,” Sladek said.
In fact, coconut oil, which contains saturated fat, produced very little changes in hypothalamic genes.
“If there’s one message I’d like people to take away from this, it’s this: Cut down soybean oil,” Deol said about their latest study.
Date March 22nd, 2020
Source: NCYT Amazings
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