How seed oils took over our diet — and what it means for our health
By Nina Teicholz, PhD
America may be poised for a nutrition policy reset, one that starts to reverse the epidemic of chronic disease afflicting a majority of Americans. With Robert F. Kennedy Jr. tapped to lead the Department of Health and Human Services, the incoming administration has an opportunity to scrutinize a once-rare but now pervasive ingredient in our diet: seed oils.
Over the last 125 years, our consumption of these oils, extracted from soybeans, peanuts, sunflowers, safflower, and other seeds and beans, has multiplied more than any other food source.
That rise has far-reaching health implications that have been downplayed or dismissed by some of our nation’s foremost nutrition experts. To turn the page on our chronic disease crisis, the new administration should initiate a thorough, science-based review of seed oils.
Seed oils were largely developed as machine lubricants during the Industrial Revolution. It was Procter & Gamble that introduced them into the food supply via its product Crisco in 1911 and aggressively marketed them as a modern-day alternative to lard.
That push got a massive boost in 1961 from the American Heart Association, when it recommended consuming polyunsaturated seed oils over saturated fats as the key strategy for preventing heart disease. This advice launched a new era for seed oils: Now they could be marketed as “heart-healthy.”
But the AHA position may have been shaped by a sizable donation from P&G in 1948, equivalent to $20 million today, that, according to the AHA, was the “bang of big bucks” that “launched” the group.
Findings of seed oil researchers have been troubling. Studies show these oils oxidize easily, which fuels inflammation. Omega-6 fatty acids in seed oils displace healthier omega-3s in cell membranes. Large, gold-standard clinical trials found that lowering cholesterol, whether through seed oil consumption or other means, increased cancer mortality rates.
By the 1980s, these findings were worrisome enough that the National Institutes of Health convened four high-level workshops. Rather than issue public warnings on seed oils, the NIH decided any concerns shouldn’t “contradict” its message about lowering cholesterol. It was a pattern — ignoring evidence of seed oils’ harm in favor of preserving prevailing orthodoxy on dietary fats.
Seed oil is chemically unstable. Its fatty acids degrade into oxidation products such as free radicals and degraded triglycerides. In one analysis, 130 volatile compounds were isolated from a piece of fried chicken, and these oxidation products can pass through the blood-brain barrier.
Industry experts are aware of these problems. Yet, public health institutions remain staunch supporters. Federal dietary guidelines still recommend consuming about 5.5 teaspoons of industrial seed oils daily while limiting saturated fats.
We made the wrong choice on good vs. bad fats. Whole, natural animal fats are stable when heated and don’t produce the same harmful byproducts as seed oils. While seed oil must be refined, bleached, deodorized, “winterized,” and stabilized in factory settings, butter requires nothing more than shaking milk in a container.
Furthermore, systematic reviews and meta-analyses on randomized, controlled clinical trials routinely find that saturated fats have no effect on cardiovascular or total mortality and little to no effect on cardiovascular events.
It’s time to correct course. The Dietary Guidelines for Americans should eliminate outdated caps on saturated fats and the new administration should prioritize a comprehensive review of the seed oils that have largely replaced them. Our policies and diets should align with science.
Nina Teicholz is a science journalist and author with a Ph.D. in nutrition. This piece originally ran in the Washington Examiner.
