Seed Oils: Toxic or Not?

The Washington Post Article

Industrial seed and vegetable oils represent the single greatest change to humanity’s diet in history. There is still a lot that we don't know about oils in general, but I can tell you from my time in France that freshly pressed olive oil is better tasting and have no preservatives.

Most seed oils are rancid when pressed and must be chemically changed for human consumption. First, let’s define “vegetable oils.” These are the oils of soybean, corn, canola, cottonseed, rapeseed, grapeseed, sunflower, safflower, rice bran, sesame, groundnut (peanut), palm, and palm kernel. The fruit oils include coconut, olive, and avocado, with trivial amounts of other oils. The enormous bulk of the consumed oil is made up of “industrial seed oils,” which, for the sake of this discussion, includes the oils of soybean, corn, canola, rapeseed, grapeseed, sunflower, safflower, and rice bran. Most of the oil consumed in restaurants and fast-food restaurants in the U.S. is derived from soybean and canola oil. They are used for some weeks and continually damaged by heat, changing their composition.

The Washington Post Article

Recently, a Washington Post article asserted that scientific evidence does not support claims that seed oils are toxic, emphasizing their safety and potential benefits when part of a balanced diet, while acknowledging the need for more nuanced discussions about processed foods and healthier oil alternatives.

The article suggests that the anti-seed oil movement, amplified by social media influencers and figures like Kennedy, often relies on misinformation. Claims about toxicity stem from concerns about omega-6 fatty acids and processing chemicals like hexane, but experts note that residual hexane levels are minimal and not harmful (they same the same about fluoride). The association of seed oils with chronic diseases is attributed to their prevalence in ultra-processed foods, which also contain high levels of refined grains, sugars, and sodium, rather than the oils themselves

The Rise of Vegetable Oils

It's worth noting that in 1900, a staggering 99% of added fats consumed were derived from animal fats like lard, butter, and beef tallow. Let's take a closer look at the numbers. In 1900, when obesity was a mere 1.2% in U.S. men, vegetable oil consumption was about 1.0 gram/capita/day. By 1961, obesity had skyrocketed to 13.4%, an 11-fold increase from the prevalence in 1900, and vegetable oil consumption had surged to 19 g/day, approximately a 19-fold increase from the 1900 level. Fast forward to 2005, and a monumental shift had occurred 86% of added fats in the diet were now derived from vegetable oils. This drastic change in our dietary habits has profound implications for our health. By 2018, obesity had risen to a staggering 42.5%, and vegetable oil consumption had reached about 80g/day (the 2010 level), about 80-fold higher than in 1900 and 4-fold higher than in 1961. These alarming trends underscore the urgent need for further research and action.

In numerous countries, studies have shown that total vegetable oil consumption has risen in direct correlation to obesity, diabetes, and most chronic diseases. I will submit that we cannot blame overeating per se for the obesity epidemic. While the ‘calories in, calories out’ hypothesis of obesity, which states that weight gain results from consuming more calories than one burn, is valid from a thermodynamic standpoint, it does not represent reality nor explain why we’re becoming progressively overweight. Something else is at play.

Consider the following: If sugar and carbohydrate consumption have been declining for an extended period, e.g., many years, while obesity and diabetes rates are rising in the same population(s) and during the same time frame(s), isn’t this evidence against their role in the etiology of these disorders? Most of the population is overweight and obese (73.6% of American adults in 2018). On average, most of the population consumes the major dietary constituents (e.g., proteins, carbohydrates, fats, seed oils, sugars, flour, etc.). If sugar and carbohydrate consumption are declining while overweight, obesity, and diabetes rates are rising, wouldn’t that suggest that something else is at play?

Seed Oils in Other Countries

Olive oil and avocado oil, which are higher in monounsaturated fats and omega-3 fatty acids, may offer additional health benefits, such as reduced cardiovascular disease and dementia risk. In addition, fresh pressed olive oil is available in many countries, especially the Mediterranean. This is a stark difference from the US and much of North America.

Petro Dobromylskyj’s most compelling argument for relatively high linoleic acid consumption being a problem is compelling. He talks about his hypothesis here. Mike Eades gave a talk on it here, which is available on YouTube. The importance of making this crucial information more widely available cannot be overstated.

There are a couple of white papers here and here from Zero Acre Farms that argue seed oils are a problem for different reasons and provide historical background, consumption trends, etc. Chris Knobbe’s book, The Ancestral Diet Revolution, goes into depth on this subject.

As for the WaPo article, I’d encourage you to look at the “outlier” study the author (Haspel) refers to. This study, conducted by Christopher Ramsden at the NIH, is significant because it challenges the prevailing view on the health effects of seed oils. Also, a 2017 meta-analysis found no significant link between omega-6 fatty acids and inflammation in humans, countering claims of pro-inflammatory effects. Haspel’s rule no. 2 in her article, “Look at all the evidence,” is bad if you don’t know how to interpret the evidence and simply tally up positive vs negative findings and see who wins. In other words, some level of “cherry-picking” is necessary to interpret the quality of the studies. We also saw this with Ancel Key’s 7-country diet-heart hypothesis studies. This underscores the need for a balanced and critical interpretation of the evidence.

Haspel points out that meta-analyses are only as good as the evidence they summarize, “and researchers can still find ways to exclude studies that contradict their worldview.” That latter part is critical for the studies Haspel includes. Ramsden is not without a worldview, but just because the results of his analyses contradict several others doesn’t necessarily make his analysis wrong. This highlights the importance of considering all viewpoints and being open-minded in the evaluation of research.

Despite these compelling relations, no randomized controlled trial has shown that the replacement of saturated fat with linoleic acid significantly reduces coronary heart disease events or deaths (article here). Also, from the Analysis of recovered data from the Minnesota Coronary Experiment - In this cohort, substituting omega 6 linoleic acid for saturated fat did not provide the intended benefits but increased all-cause of morality, cardiovascular death, and death from coronary heart disease.

Most Nutrition Studies are Wrong

And it's also important to remember that most nutrition studies are poorly done and not valid. Stanford professor, John Ioannidis, has extensively critiqued the reliability of nutrition studies, arguing that most are not repeatable due to inherent methodological flaws. He contends that the field of nutritional epidemiology heavily relies on observational studies, which are prone to confounding factors, recall biases, and inaccurate dietary measurements, such as self-reported questionnaires that often yield implausible data (e.g., energy intake incompatible with survival). These studies typically produce weak associations that fail to hold up in randomized controlled trials (RCTs), which he considers the gold standard for establishing causality. In a 2018 JAMA commentary, Ioannidis called for a "radical reform" of nutrition research, advocating for large-scale, long-term RCTs over observational studies to generate reliable evidence. He has highlighted absurd findings, like claims that eating specific foods (e.g., hazelnuts or eggs) drastically alter life expectancy, as examples of how biases and selective reporting produce misleading results. Critics like Walter Willett argue that observational studies still have value when measurement errors are addressed, but Ioannidis insists that their limitations often outweigh their utility, leading to contradictory and unreliable conclusions that confuse public health guidelines.

It's apparent that consuming fresh-pressed oils overall is better for health. Maybe that's true for other seed oils. But the truth is that 99% of Americans don't use fresh-pressed oils or even have access to them.

In conclusion, the widespread adoption of industrial seed oils, such as soybean and canola, marks a profound shift in human dietary patterns, with far-reaching implications for public health. The consistent correlation between rising vegetable oil consumption and the global surge in obesity, diabetes, and chronic diseases raises critical questions about their role as a primary driver of these conditions. Unlike other dietary components, these oils exhibit a unique and robust link to adverse health outcomes, particularly when damaged by repeated heating in restaurant settings. As we continue to grapple with escalating health crises, it is imperative to scrutinize the pervasive use of industrial seed oils and consider prioritizing whole, minimally processed foods to safeguard our collective well-being.

Refs

BMJ 2016;353:i1246 | doi: 10.1136/bmj.i1246

https://www.bmj.com/content/346/bmj.e8707.full

Christopher Knobbe’s book, The Ancestral Diet Revolution