Polyunsaturated Fats Are Not Healthy Cooking Oils
Stay away from grapeseed oil whenever possible. Certainly don’t cook with it. It’s way too high in polyunsaturated fats (also known as PUFA, short for polyunsaturated fatty acid).
The unstable molecular structure of unsaturated fats, especially PUFA, makes them prone to damage from light, heat, and oxygen. When unstable fats get damaged, they oxidize.
Oxidation = the process of going rancid, which creates free-radicals. Among their many undesirable effects, free-radicals damage cells, and promote aging, cancer risk, and build-up of arterial plaque.
It is criticial to limit high-PUFA-containing foods.
A compelling study published in The Lancet demonstrates
- arterial plaque (the accumulation of which can lead to heart disease) is not associated with saturated fat, but unsaturated fat (polyunsaturated, along with monounsaturated), and
- adipose tissue (stored fat, often located around the waistline, that is lined to heightened disease risk) is largely associated with unsaturated fat:
Positive associations were found between serum and plaque omega 6 (r = 0.75) and omega 3 (r = 0.93) polyunsaturated fatty acids, and monounsaturates (r = 0.70), and also between adipose tissue and plaque omega 6 polyunsaturated fatty acids (r = 0.89). No associations were found with saturated fatty acids. These findings imply a direct influence of dietary polyunsaturated fatty acids on aortic plaque formation and suggest that current trends favouring increased intake of polyunsaturated fatty acids should be reconsidered (1).
Which foods are highest in PUFA? The majority of nuts and seeds, and oils derived from said nuts and seeds. Think:
- grapeseed oil
- canola / rapeseed oil
- soybean oil (technically soy is a “legume”)
- safflower oil
- sunflower oil
- cottonseed oil
- sesame oil
- rice bran oil
- even good ol’ flax, chia, hemp and walnut oils.
These are all highly unstable oils. These are not oils for cooking. And yet, most of these oils are rampantly marketed as cooking oils.
The Source of the Hype
Why do we hear so much about plant oils like grapeseed and canola for cooking? Because, even if they’re organic, they’re still cheap to produce. The lower the production cost, the greater the tendency for manufacturers to aggressively market a product in order to drive profits. This is the way the food industry works (it ain’t called an industry for nothin’!).
Flax, Chia, Hemp and Walnut Oils Are NOT Healthy Cooking Oils!
Granted, oils like flax, chia, hemp and walnut are not often suggested for cooking, though I do see it on occasion, and when I do I slap my forehead–hard. More often, I run across suggestions to bake with these oils’ food-sources, like flax meal (ground flax seeds)–talk about oxidation city!
In any case, oils like flax, chai, hemp and walnut should also be limited to small amounts even when unheated because they, too, negatively affect plaque levels–largely so: that same study mentioned earlier found omega-3 polyunsaturated fatty acids were also largely linked to plaque formation. This would be because omega-3 PUFA is the most unstable variety of PUFA, and the most unstable of all unsaturated fatty acids (PUFA and MUFA), a fact in nutritional biochemistry that sharply calls into question the extent of flax, chia, hemp and walnut oils’ “healthy” status.
The Fats We Need the Most Of
Make no mistake: all fats are necessary, but we don’t need as much of some as we do of others. We need less unsaturated fats. We need more saturated fat.
As I repeat like a broken record in my book: the most stable fat is saturated fat. Then comes monounsaturated fat (MUFA). Then polyunsaturated fat (PUFA). The results of the study cited earlier support this sequence.
Why Olive Oil Isn’t the Healthiest Cooking Oil
Just because MUFA outranks PUFA in terms of stability doesn’t mean you should go to town with it for cooking, and even for eating. Remember: MUFA is an unsaturated fat, so it is incapable of providing the healthy high levels of stability that saturated fats do. Research suggests an association between MUFA and arterial plaque formation (2). Higher-MUFA plant oils include
How To Use Olive Oil & Other High-MUFA Oils
Eat smaller portions of MUFA oils, and add to food after you cook said food. Technically, you can cook with MUFA if you steer clear of higher-heat temperatures, but most people cook at very high temperatures.
Personally, the only times I cook with MUFA oils, like olive oil, are the rare occasions when I run out of my high-saturated fat cooking oils and fats (I’m talkin’ tub-size).
Also, make sure you only buy varieties of MUFA oils that are cold-pressed (not exposed to heat during extraction), as close to extra virgin as possible, and come in dark-tinted glass bottles. Keep bottles tightly sealed. I constantly run across roasted nut oils, and oils stored in clear plastic or glass bottles–which means the unsaturated oils have already been exposed to light, high heat and/or chemical-ridden plastics, and are therefore damaged. Lame. Not what you want!
Saturated Fat Is the Healthiest Cooking Oil
Again, you want to cook with oils that are mostly saturated fat because saturated fat is the most stable kind of fat in existence.
To boot, when you cook with it, saturated fat optimally protects the foods you cook from damage. Talk about a win-win. Healthy, stable, high-saturated fat oils include:
- coconut oil
- palm oil
- lard/tallow from pastured animals
- pasture butter or clarified butter/ghee.
Stick with the healthiest cooking oil: saturated fat.
Read more about saturated fat in my article Why Is Saturated Fat Good for You?
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