The Four Insidious Ways Seed Oils Destroy Your Health

15 min read

What you’re getting yourself into

A thorough but very easy to grasp breakdown of what seed oils are, how they came to be seen as healthy foods, and most importantly, why they have been the architects of our chronic disease epidemic.

We’re forever being told that one particular ingredient in the food supply is the architect of the modern epidemic of chronic disease, and the reason that obesity has skyrocketed by 3400% in the last century.

Some people say it’s red meat, with its dangerously high protein content, and all the crazy things it does to balance your cholesterol.

Others point the finger at sugar, with its similarity to cocaine on our dopamine mechanics, the lack of nutrition, and the burnt-toast consequences of advanced glycation end-products.

Then there are the smaller conspiratorial niches, like the permutations of gut-ripping gluten, antinutrients like phytic acid, or even the deuterium in our water supply.

Don’t ask me what the last one is about, because I haven’t the faintest idea even after listening to a couple of podcasts. I’m smart, but not that smart.

Many of these conspiracies have compelling mechanisms, but don’t pan out so well when one looks at the data. Sugar being the prime example. But the harbinger of human health has another contender that has been picking up a head of steam lately.

This player often goes by the name ‘vegetable oils’, but that’s just clever marketing. In truth, it has little to do with vegetables, it’s just that vegetables are universally seen as a good thing, and that helped its case as the healthy replacement to the controversial saturated fat.

That’s why I’d prefer to simply call them seed oils, because they’re extracted from seeds of plants. In fact, you could also refer to them as factory fats, since the process of harvesting and bottling these oils is ridiculously mechanised.

How Seed Oils Are Made

how seed oil is made
  • First nutrient-bereft oil is squeezed out from the seed using intense pressure
  • Then it’s treated with solvent
  • Then bleached to mask the rancidity
  • Then distilled
  • Debunked
  • Deoderised
  • Winterised
  • Stabilised
  • Finally treated with a chelate to remove toxic metals

That’s quite a bit of work when you compare it to carving up a cow and shaving some of the fat to make tallow. It shouldn’t be surprising to note that seed oils weren’t a thing before 1860, because we didn’t have the means, or the motivation, to hatch them up.

As a magazine put it succinctly:

“What was garbage in 1860, was fertilizer in 1870, cattle feed in 1880, and table food and many things else in 1890.”

The landscape changed further with the beginnings of the animal fat controversy, with debates on the ethics on slaughterhouses, as well as the suspicion placed around its roles in heart disease and cancer.

That created the perfect environment for seed oils to emerge from the periphery and chart their path to dominance in the human cuisine, by making their case across a few vital points.

A – They were cheaper to produce – Big food loved that.

B – They lowered cholesterol – The Seven Countries Study in 1959 underlined the cholesterol hypothesis which incriminated saturated fat as the driver of heart disease by virtue of raising of cholesterol.

The healthy donation to the American Heart Association (AHA) by Procter and Gamble, the inventors of the seed oil margarine Crisco, also helped seal the legitimacy of this cholesterol theory. Which never made its way past theory into actual scientific evidence, but that couldn’t stop it from being engrained in nutritional guidelines across the globe.

The last century has seen a seismic change in the makeup of added fats in the diet, with seed oils going from less than 1% in 1900, to a colossal 86% in 2018.

And it just so happens that obesity has skyrocketed by 3400% in the last century, along with many chronic diseases that were collectors items at the dawn of the 20th. Like red meat’s worst enemy, coronary heart disease (CHD).

Coincidence? I wish.

Seed Oil’s Sketchy Track Record

dark history of seed oils

The Seven Countries Study put the seal of approval on the cholesterol hypothesis, submerged itself in nutritional guidelines, and paved the way for seed oils to be consumed on a mass scale.

They just forgot one key step, validating the hypothesis that displacing animal fats for seed oils made for better health outcomes and prevented CHD.

Not that they lacked for trying. As a recent example, the 2013 randomised Sydney Diet Heart Study compared people eating butter and animal fats, with another group eating seed oils, total fat being equated. Not only were the seed oil group in worse shape, they displayed a 62% high rate of death.

Only two diet and lifestyle factors have been shown to have worse outcomes. Smoking, and morbid obesity. Consuming seed oils puts you at worse risk than physical inactivity and heavy drinking.

Incidentally, the Sydney Diet Heart Study was actually conducted in the 1960s. The findings were suppressed, then finally resurrected in 2013. An understandable reaction when your study delivers the complete opposite result to the one you’re spent millions seeking out.

This wasn’t the only long-lost seed oil study that reappeared with undesirable outcomes. The Minnesota Coronary Experiment, which ran between 1968 and 1973, was republished in 2016 with raw data that had been found festering in a box in the far corner of a basement.

The results confirmed that replacing animal fats with seed oils successfully lowered cholesterol by 14%. Unfortunately, the seed oil group also had an 86% greater incidence of heart attacks. A mixed bag.

The evidence doesn’t just show that there isn’t a line of causality between saturated fat and heart disease, it strongly suggests that the replacement of saturated fat with polyunsaturated fats from seed oils has bestowed humanity with a turn for the worse.

Take Israel as a broader example. They are the poster child for the wonderful Mediterranean diet that was piloted by the aforementioned cholesterol crusader Ancel Keys. Their diet is low in total fat, low in saturated fat, and high in seed oils. They also happen to be on par with the USA in obesity.

The cholesterol experiment has failed. Seed oils haven’t delivered on their promises to magick humanity back into good health by dropping cholesterol. Billions of us have been used as guinea pigs thanks to guidelines that had nothing but sketchy epidemiological data (junk) to stand on.

At this point you should be wondering just what it is about seed oils that makes them so hazardous to our health. I’ve got four reasons why this concoction is the worst of the modern slow poisons.

1. Inflammation

inflammatory effects of seed oils

This is the one effect of Omega 6 that we’ve known for the longest time, starring in the arguments for ancestral nutrition. Omega 6 is inflammatory, and that’s mainly due to linoleic acid leading to the production of arachidonic acid, which itself is a precursor to pro-inflammatory mediators that include prostaglandins and leukotrienes.

These pro-inflammatory mediators can play a role in heart attacks and strokes, but those effects can be mitigated by the presence of compounds like resolvins, protectins, and maresins. All of which come from Omega 3, and that’s why the much-vaunted Omega 6:3 ratio has been constantly brought up as the marker of how humanity has lost its way since the palaeolithic days.

The ratio used to be down to a flat 1:1 in the era of megafauna, while it has since risen into the stratosphere, all the way up to 20:1.

But let’s keep going.

2. Oxidation

oxidative stress from seed oils

The first and most important of the seed oil hazards, is the propensity to heighten oxidative stress. And given that oxidation is the chief driver of chronic disease, this can cause major problems down the line.

If you’re unfamiliar with just what oxidation is, you can think of it as rusting on the inside. It’s a natural process involving free radicals that, when allowed to run rampant and unabated, can cause untold damage to the mitochondria, building incessantly towards disease and dysfunction.

Healthy Mitochondria Are The Key To Reversing Aging

The issue with seed oils is that they’re predominantly made of polyunsaturated fats (PUFAs), in this case Omega 6. PUFAs are inherently unstable due to their double bond structure, and are highly vulnerable to being oxidised. Since some of the fats you ingest inevitably become part of your cellular structure, you’re being primed for chain reactions through free radical damage.

A good way to look at this would be if you attempted to weld something with dry paper strewn across the floor. At some point a spark is going to land on the paper, and it’s not going to end there.

And it isn’t just a case of high Omega 6. Plenty of other plant foods have high levels of linoleic acid, like nuts and seeds. Even pork and chicken fat is 20-25% Omega 6. While seed oils provide more concentrated amounts, part of the problem lies in the intense processing it takes to extract the oil from its normally unobtainable natural form. The heating by itself ensures that your bottle of organic rapeseed oil is rancid (oxidised) on arrival.

We’re all pretty familiar with the fear mongering over LDL cholesterol’s role in atherosclerosis, and saturated fat’s propensity to raise it. It’s the oxidation to the LDL particles that happens to cause macrophages (white blood cells) to swallow them up and form clumps on the arterial walls. If the LDL wasn’t oxidised, the macrophages wouldn’t have any danger to deal with, and the plaques wouldn’t materialise. We’ve known this for decades.

In other words, saturated fat raising LDL shouldn’t be a cause for concern, but you should definitely be worried about the oxidative damage that seed oils inflict on LDL.

This graph shows the peroxidation index, or susceptibility to oxidation, of different dietary fats. Seed oils are in a category of their own.

how different fats are oxidised

And while buying cold-pressed versions instead is certainly a better option, you still have to worry about exposure to light or oxygen during the making and transport of that oil, then finally the incendiary consequences of filling up your fat stores with brittle Omega 6.

In case you’re wondering about how this tracks with Omega 3 in fish, since that’s also PUFA, don’t worry too much. Oil can go rancid without you detecting it, but if your cut of wild salmon is rancid, your nostrils will know about it. The same goes for pork and chicken.

Just don’t make them the centrepiece of your diet, and stay the hell away from fish oil capsules. Those will almost certainly be rancid, and they actually rank higher on the peroxidation index than seed oils.

3. Toxicity

toxic aldehydes in seed oils

When seed oils go rancid, the danger isn’t restricted to oxidative damage by free radicals. It also leads to the formation of lipid hydroperoxides. They are highly unstable and rapidly decompose into other dangerous compounds, such as HNE, MDA, acrolein, and carboxyethyl pyrrole.

I’m not entirely sure how the last one gets pronounced. Thankfully we can simply group them under advanced lipid oxidation end products, or ALEs.

But what I do know is unlike the free radicals, which cause chaos but lead mercifully short lives, ALEs are stable enough to roam around your tissues, exacting permanent damage against your DNA, proteins, and lipids.

And there’s not just four of them. There are hundreds.

4. Nutrient Depletion

nutrient depletion in seed oils

There is no upside to seed oils. They are nutritionally bereft, completely lacking any of the fat-soluble vitamins A, D, and K. Which would otherwise be sourced from the animal fats that they were designed to replace.

It’s nearly a century since researchers found out that they could bring animal growth to a halt if those animals only had seed oils as their fat source.  That shouldn’t have boded well for humanity’s mission to replace the maligned saturated fats with industrial lubricants.

Deficiencies in these vitamins can lead to a number of degenerative conditions including dental decay, arthritis, cancers, and a reduction in resistance to infectious diseases.

The fact that seed oils lower cholesterol should also be a matter of concern. Cholesterol is essential to life, being a precursor for hormones, Vitamin D, and bile acids, as well as stabilising cell membranes. Low cholesterol itself is linked to memory loss, heart failure, depression, aggression, and muscle loss.

Seed oils lower cholesterol by providing phytosterols instead, the plant variants that the human body has no interest in using. The body actively flushes out incoming phytosterols at the expense of absorbing cholesterol, resulting in an artificial denting of your cholesterol numbers.

This means the seed oils don’t normalise cholesterol, they lower it below baseline.

And animal fats don’t cause high cholesterol, they let it return back to the baseline.

Effects Of Seed Oils

  • Asthma
  • Autoimmune disease
  • Mental health disorders
  • Diabetes
  • Obesity
  • Heart disease
  • Gut dysfunction
  • Inflammation
  • Infertility
  • Macular degeneration
  • Osteoarthritis

Wrapping Up

plant fats vs animal fats

Seed oils are biological poison, and have no place in the human diet. They are pro-oxidative, pro-inflammatory, form toxic byproducts, and have absolutely no nutritional value. As such, the recommended intake should be somewhere around zero. Unfortunately, eliminating them completely can be difficult, although not impossible.

The Seed Oil Hateful 8

  • Canola Oil (Rapeseed)
  • Corn Oil
  • Soybean Oil
  • Cottonseed Oil
  • Sunflower Oil
  • Safflower Oil
  • Grapeseed Oil
  • Rice Bran Oil

And despite being nonexistent 150 years ago, they’re everywhere at this point.

Common Foods That Contain Seed Oils

  • Margarine
  • Baked Goods
  • Candy
  • Ice Cream
  • Coffee Creamer
  • Dairy-Free Cheese
  • Oat Milk
  • Potato and Corn Chips
  • Fried Food
  • Crackers
  • Vegetable Shortening
  • Frosting
  • Salad Dressing
  • Mayonnaise
  • Pre-Made Dough
  • Microwave Popcorn
  • Pre-Packaged Nuts and Seeds
  • Pre-Packaged Snack Foods
  • Baby Formula

The solution has to be to avoid processed food as much as possible, and cook at home with animal fats. A carnivore diet is naturally devoid of seed oils, and you might be inclined to score some extra points by limiting chicken and pork in order to restrict Omega 6. The linoleic acid in meat won’t be oxidised, but it will still be problematic when allowed to build up in your fat stores and line the cell membranes.

While you might be tempted to swap in olive oil for seed oils, keep in mind that even extra virgin olive oil is often adulterated with seed oils and not up to standard. Beyond that, as a monounsaturated fat, it is still relatively unstable and oxidises quickly when heated.

Just forget about the government guidelines that have only caused the health of humanity to spiral further, and use animal fats, since they are the most shelf and heat stable, and contain the crucial fat soluble vitamins.

Why You Need More Saturated Fat

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