Scale, scale, atop the floor

Which oil fattens me the more?

A greater degree of obesity and diabetes results from a diet high in soybean oil than one high in fructose or coconut oil, UC Riverside scientists say in a study released Wednesday.

The study, published in PLoS One, was performed on mice.



If confirmed in people, that's startling news. Fructose, found in high-fructose corn syrup, has been condemned in various places as an especially malignant trigger of diabetes and obesity. Sugar in general is blamed for spreading obesity.

The study extends earlier UCR research that found oil from genetically modified soybean oil beans is less prone to cause insulin resistance than oil from non-GMO soybeans, but otherwise is no healthier.

Coconut oil is viewed skeptically because it has more saturated fats than soybean oil, presumably increasing the risk of heart disease.

Soybean oil, obesity and diabetes

But the study, led by Frances M. Sladek, a UCR professor of cell biology and neuroscience, adds to evidence that labeling categories of foods as simply "good" or bad" simplifies a more complex, messy, reality.

--Not all triglycerides are bad, despite their routine measurement as an indicator of heart risk.

--Some studies find that current dietary recommendations to increase consumption of polyunsaturated fats and decrease consumption of saturated fats aren't justified by the evidence.

--Even salt, long the target of campaigns to lower use to reduce heart disease, has been found to have unexpected benefits.

In short, many things long regarded as confirmed truths about nutrition are in fact very debatable.

And so it is with soybean oil, the UCR study found.

“This was a major surprise for us — that soybean oil is causing more obesity and diabetes than fructose — especially when you see headlines everyday about the potential role of sugar consumption in the current obesity epidemic,” said researcher Poonamjot Deol, the paper's first author, in a UCR statement. She directed the project in Sladek's lab.

The high-fat diets, which contained 40 percent fat, produced unpleasant effects on the male mice tested. Some effects were more unpleasant than the others.

"C57/BL6 male mice fed a diet moderately high in fat from coconut oil and soybean oil (SO-HFD, 40% kcal total fat) showed statistically significant increases in weight gain, adiposity, diabetes, glucose intolerance and insulin resistance compared to mice on a diet consisting primarily of coconut oil (HFD)," the study stated. "They also had fatty livers with hepatocyte ballooning and very large lipid droplets as well as shorter colonic crypt length."

And there's more.

"While the high fructose diet (F-HFD) did not cause as much obesity or diabetes as SO-HFD, it did cause rectal prolapse and a very fatty liver, but no balloon injury," the study stated. "The coconut oil diet (with or without fructose) increased spleen weight while fructose in the presence of soybean oil increased kidney weight."

"Taken together, our results indicate that in mice a diet high in soybean oil is more detrimental to metabolic health than a diet high in fructose or coconut oil," the researchers concluded.

Scientists found out long ago that all fats are not the same, and some actually have beneficial qualities for health. Monunsaturated fats, found in avocado oil, are considered healthy.

Even butter, once held out for shame as a source of saturated fat, now looks more benign compared to margarine, introduced as a healthier alternative to butter. Some margarines contain trans fats, now known to be particularly unhealthy.

And if new research holds up, butter and whole milk may come back into vogue as a way to ward off pre-diabetes.