Trans fats of animal origin

February 27, 2014 by Michael Greger

Trans fats are bad. They can increase the risk of heart disease, sudden death, diabetes, and possibly even mental illness. Trans fats have been linked to aggressive behavior, impatience, and irritability.

Trans fats are mostly found in only one place in nature: in the fat of animals and humans. The food industry, however, has found a way to artificially create these toxic fats by processing vegetable oil. In this process, called hydrogenation, the atoms are rearranged to make them behave like animal fats.

Although America traditionally consumes most trans fats from processed foods containing partially hydrogenated oils, a fifth of the trans fats in the American diet are animal-based. Now that cities like New York have banned the use of partially hydrogenated oils, consumption of manufactured trans fats is declining, with about 50 percent of America’s trans fats now coming from animal products.

What foods contain significant amounts of trans fats? According to the Department of Nutrients’ official database, cheese, milk, yogurt, hamburgers, chicken fat, turkey meat and hot dogs top the list and contain approximately 1 to 5 percent trans fat.

Are those few percent trans fats a problem? The most prestigious scientific body in the United States, the National Academy of Sciences, has concluded that the only safe intake for trans fats is zero. 

In a report condemning the consumption of trans fats, scientists could not even assign an upper allowable daily intake limit, because “any intake of trans fats increases the risk of heart disease.” It may also be unsafe to consume cholesterol, highlighting the importance of cutting down on animal products.

The latest study confirms the view that consumption of trans fats, regardless of their source of animal or industrial origin, increases the risk of developing cardiovascular disease, especially in women, as it turns out. “Because trans fat consumption is inevitable in a normal, non-vegan diet, reducing trans fat intake to zero will require significant changes in nutritional regulations,” the report says. 

One of the authors, director of the Harvard University Cardiovascular Program, famously explained why, despite this, they do not recommend a vegetarian diet: “We can’t tell people to completely give up meat and dairy products,” he said. “But we could tell people that they should become vegetarians. If we were really only based on science, we would look a bit extreme.” Scientists don’t want to rely on science alone, do they? However, the report concludes that the consumption of trans fatty acids should be reduced as much as possible, while the intake of nutritionally adequate food is essential.

Even if you’re a strict vegetarian, you should know that there’s a loophole in the labeling rules that allows foods with less than 0,5 grams of trans fat per serving to be labeled “trans-fat-free.” This label misinforms the public by allowing products to be labeled trans fat-free when, in fact, they are not. So to avoid all trans fats, cut out meat and dairy products, refined oils, and anything with partially hydrogenated ingredients, no matter what the label says.

Unrefined oils, such as olive oil, are supposed to be free of trans fats. But the safest are whole food sources of fat, such as olives, nuts, and seeds.  


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