We’re all familiar with the harmful effects of sugar, especially fructose content in processed foods. But a new study by American scientists has shown that elevated content of soybean oil in a diet is even more harmful and causes more obesity compared to fructose.
Researchers from the University of California, Riverside (UCR) performed an experiment on male mice by feeding them with a series of four diets that consisted of 40 percent fat – the same amount Americans intake at present. In one diet the research team utilized coconut oil that primarily comprises of saturated fat while in the second diet nearly half of the coconut oil – the same amount of soybean oil Americans intake at present, was substituted by soybean oil that primarily comprises of polyunsaturated fats and is a chief constituent of vegetable oil.
The other two diets had fructose in it, equivalent to the amount several Americans intake at present. All the four diets had the same number of calories and there wasn’t any considerable disparity in the quantity of food consumed by the mice.
The team discovered that the diet with soybean oil showed elevated weight gain, larger fat residues, and a fatty liver with indications of diabetes, insulin endurance and injury – all of which are symbols of the Metabolic Syndrome, in comparison to the diet with coconut oil.
Although the fructose diets showed less acute metabolic syndrome compared to soybean oil it posed bigger risks on the kidney and indicated a noticeable rise in prolapsed rectums – a symptom of inflammatory bowel disease (IBD) that is also a major concern like obesity.
The mice on the soybean high diet gained most weight compared to the mice of fructose and soybean oil. The mice on soybean high diet gained nearly 25 percent more weight than the mice on the coconut oil and 9 percent more weight than the mice on fructose high diet, while the mice on fructose high diet gained 12 percent more weight than the ones on coconut oil high diet.
The paper explained why and how soybean oil and fructose consumption increased recently in the U.S. It said that earlier researches in the 1960s showed a positive connection between saturated fatty acids and the risk of cardiovascular disease – heart attacks and strokes. Owing to this, people commenced to follow nutritional rules that urged them to cut short their consumption of saturated fats and raise the consumption of polyunsaturated fatty acids contained in plant oils like soybean oil.
At this time fructose consumption also increased in the U.S. Besides encouraging people to cut short on the intake of saturated fats, the rise in the cultivation of soybeans also boosted the consumption of more soybean oils, which now amounts to 60 percent of edible oil eaten by Americans. On the other hand, fructose consumption rose from 37 grams per day in 1977 to nearly 49 grams per day in 2004.
The research team performed a widespread evaluation of alterations in gene expression as well as metabolite levels in the livers of the experimented mice too. They discovered that intake of soybean oil considerably affects the expression of several genes that metabolize drugs and other foreign elements, which enter the body. It indicated that if human bodies show the same response as that of the mice used for the research, soybean oil consumption could affect one’s reaction to drugs and environmental toxicants.
Poonamjot Deol, an Indian-based assistant project scientist who directed the project said that the research was a “major surprise” to the team “that soybean oil is causing more obesity and diabetes than fructose.”
Although the research is the first of its kind to discover the negative effects of consuming soybean oil, the researchers alerted that they are yet to learn the impacts of the diets on cardiovascular diseases, especially when intake of vegetable oils could be good for cardiac health – albeit it triggers obesity and diabetes too.
The research team who are currently doing experiments with lard and olive oil, did an experiment with corn oil as well and discovered that it also triggers obesity, but not nearly as much as soybean oil.
They are yet to experiment with canola oil or palm oil.
The paper titled “Soybean oil is more obesogenic and diabetogenic than coconut oil and fructose in mouse: potential role for the liver” has been published in the July 22 issue of the journal Plos One.
According to WHO, obesity has experienced a two-fold increase since 1980. In 2014 more than 1.9 billion adults were overweight and over 600 million were obese. In 2013, 42 million children under the age of 5 were reported to be overweight or obese.
According to WHO, in 2014 the occurrence of diabetes was guesstimated to be 9 percent in adults, across the world. In 2012 approximately 1.5 million deaths were reported directly diabetes 2. WHO predicts that by 2030, diabetes will become the 7th leading cause of death in the world.