Seed oil toxicity: Trend or truth?

Controversy Over Seed Oil Toxicity 

If you’re being more conscious about the presence of seed oils in the foods you and your family eat, you’re not alone. This has become a big deal over the past few years and I gotta admit I’m partly to blame for this. I wrote about their toxicity in my earlier books, and changed how the Lakers eat. The results were astounding.

In the past 12 years, there has been a significant shift in the way people think about the health effects of vegetable oils, with more vegetable oil-free products appearing on grocery store shelves. Still, most of our foods are soaking in these nasty oils.

I think this is because doctors are scientists at heart. We are conservative thinkers. I’m not talking politically conservative. I mean in the sense that we are loathe to adopt new ideas unless presented with sufficient data. I needed to read entire textbooks and thousands of scientific publications before I was convinced that support for my entire nutrition education rested on nothing but a house of cards.

Extraordinary claims require extraordinary evidence.

Doctors have been told for decades that vegetable oil is good for you, so it’s understandable that they would find the notion that maybe they’re not so great to be an extraordinary claim.

I’m happy to say that the number of people steering clear of seed oils is growing larger every year since the first publication of Deep Nutrition in 2009. It’s now become a small army. But the anti-seed-oil movement also seems to have spawned an army of armchair quarterbacks who are creating a bit of a problem. Although they get the gist of the message and are giving better diet advice than most doctors, getting the gist is not enough. In order to convince trained physicians and dietitians to abandon long-held beliefs, you have to have more than a little knowledge. Ultimately, they’re sending the message that maybe this whole seed oil movement isn’t ready for prime time.

The devil’s in the details and a little knowledge is a dangerous thing. So let me help clear things up a bit by discussing four of the claims buzzing around the web that health professionals are likely to run into. Together, they discourage further interest in looking into the health effects of these oils, effectively waiving off most otherwise interested professionals. I’ll also give you the necessary details that put these claims in a different light.

What they Hear: Linoleic acid is the reason for seed oil toxicity.

Linoleic acid is a polyunsaturated fatty acid found in high concentrations in seven of the eight members of the Hateful Eight. 

The disconnect:

Linoleic acid is not the problem with seed oils. The problem is the oxidation reactions that occur during manufacturing of these oils, and that continue to occur after they leave the factory. They also occur in the bottle after you open it, in the food as you’re cooking with it, and in your body, after you eat it.

What they hear: Seed oils are bad because they contain hexane.

Hexane is a known carcinogen used in the processing of vegetable oils. Even though it is present in trace amounts in non-organically labeled vegetable oil products, it’s a major reason that vegetable oils should be avoided at all costs. 

The disconnect:

Hexane is bad but it’s not the major problem.

No doubt hexane is not good for you. No one would question that. But according to the doctor I mentioned earlier, we inhale quite a lot more hexane when we fill up our cars with gas than what we eat when we eat foods cooked in canola. I have no reason to doubt that claim. But that’s not the reason to avoid vegetable oils at all costs. The reason is it’s a fireworks display of lipid oxidation products. You can learn more about one such byproduct here: “Formation of modified fatty acids and oxyphytosterols during the refining of low erucic acid rapeseed oil.”

What they hear: Seed oils are inflammatory because of an omega-6 to -3 ratio imbalance.

The idea here is that many seed oils are high in omega-6 linoleic acid, and that is an “inflammatory” compound. 

The disconnect.

Seed oils promote inflammation due to oxidative stress, not because of their linoleic acid content.

Although its true that linoleic acid can be metabolized into an inflammatory eicosanoid that can promote things like blood clotting and tissue swelling, linoleic acid cannot. It takes several biochemical steps to be converted into that inflammatory eicosanoid, and each of the several necessary steps only happens under certain circumstances. Cells are tiny control freaks, and they tightly regulate each of those several necessary steps.

A diet rich in pro-oxidative seed oils undermines the cell’s ability to regulate these and every other process.

What they hear: Human trials fail to prove seed oil toxicity.

There is an apparent absence of studies showing that these oils are toxic. Indeed, there are numerous studies seemingly showing the opposite. Mazola bottles claim their corn oil is “heart-healthy.” If these oils are so toxic, where is the hard data?

The disconnect:

Medical science has been operating without any understanding of oxidation for so long that it rarely even enters the research process. When it does, it’s with a superficial understanding of the necessary information. Therefore, oxidation, rather than being a central focus of nutrition research, is at best an afterthought.

Researchers are people. They’ve heard the same mantra that we’ve all heard for the past 70 years, that animal fats are bad and vegetable oils are healthy. This means they go into nutrition research with a foregone conclusion.

With that in mind, you might wonder why do research at all?

Here’s where we need to understand the connection between politics and food. This is a whole other discussion that deserves its own article. I’ll provide links to some excellent lectures on the topic, below.

It boils down to feeding the masses from the bottom of the food chain where calories are easier to produce for an ever-growing population. In the battle for funding dollars, the winners tend to be those researchers whose messages align with that goal. This goes back to Ancel Keys and the diet-heart hypothesis and continues with the Adventist physicians who distort their research.

When you’re talking nutrition, you’re talking biochemistry. The subject of biochemistry does not readily lend itself to sound bites. But if you want one, I’ve got one for you. Get seed oils out of your life, now.

Not convinced? Read my new book, Dark Calories.

Read more about Dr Shanahan, her other best-selling books and her work at DrCate.com