Soybean oil, the vegetable cooking oil commonly used in the United States,
is also gaining popularity worldwide. Researchers at the University of
California, Riverside (UCR) tested a genetically modified (GM) soybean oil
used in restaurants, and found that while it induces less obesity and
insulin resistance than conventional soybean oil, its effects on diabetes
and fatty liver are similar to those of conventional soybean oil.
The researchers tested PlenishR, a GM soybean oil released by DuPont in
2014, engineered to have low linoleic acid, resulting in an oil similar in
composition to olive oil, the basis of the Mediterranean diet and considered
to be healthful. The study also compared both conventional soybean oil and
PlenishR to coconut oil, which is rich in saturated fatty acids and causes
the least amount of weight gain among all the high-fat diets tested.
"We found all three oils raised the cholesterol levels in the liver and
blood, dispelling the popular myth that soybean oil reduces cholesterol
levels," said Frances Sladek, a professor of cell biology, who led the
The research team also compared PlenishR to olive oil. Both oils have high
oleic acid, a fatty acid believed to reduce blood pressure and help with
weight loss. They found that olive oil produced identical effects as
PlenishR - more obesity than coconut oil, although less than conventional
soybean oil - and very fatty livers, which was surprising as olive oil is
typically considered to be the healthiest of all the vegetable oils.
"PlenishR, which has a fatty acid composition similar to olive oil, induced
hepatomegaly, or enlarged livers, and liver dysfunction, just like olive
oil," said Poonamjot Deol, co-first author of the research paper.