Cooking Oil 101

“If you’re afraid of butter, use cream.”

- Julia Child

To much of America, refined vegetable oil is a ubiquitous, neutral ingredient, one we simply don’t think about very much. Most people just think figure that it’s clear, comes from vegetables, and cheaper than olive oil. It’s familiar, and therefore accepted as food.

We shouldn’t eat a lot of it, we’re told, because it’s an oil, but it’s better than those artery-clogging saturated animal fats our ancestors ate, especially when it says “lite” on the bottle. Although, we’re also told, it’s not as good as olive oil, which is, of course, the only fat they use in the Mediterranean (some country between Sardinia and Souvlakia where the healthy, tanned population basks all day on beaches).

It turns out that much of what we’ve been told about oil is wrong. Processed, refined vegetable oils, which aren’t exactly squeezed out of vegetables, are far from harmless foods, if you can even call them foods. For the most part, they’re extremely detrimental, particularly due to high levels of omega-6 polyunsaturated fatty acids. They’re also highly processed. Olive oil is fine, but a) it’s not the only fat used around the Mediterranean and b) using it at the exclusion of saturated animal fats can mean missing out on some important fat-soluble vitamins. Vitamin-rich saturated fats are an important part of a healthy diet.

What’s true for most foods is true for fats too: The best fats in your food are simple, naturally-occurring fats that cultures have prized for thousands of years. This includes mostly animal fats, like butter, beef tallow, lard, and schmaltz, and vegetarian fats like unrefined coconut oil, unrefined red palm oil, and olive oil. These fats, like Julia Child implies in the quote above, are nothing to fear. But their loss from our diet is indeed something to fear.

Here, then, is a beginning guide to cooking oils and fats. I’ll go over a few rudimentary concepts. At the bottom, you’ll find a chart with some basic information about certain fats and oils you can use in your kitchen.

These Are Not Vegetables

“Vegetable oil” is such an innocuous term. Didn’t Mom tell you to eat your vegetables? However, so-called vegetable oils are made out of seeds and grains, like soy or corn. In some cases, like cottonseed oil, the oils are made from sources that aren’t even considered foods at all.

Vegetable oil is fairly new and, with the exception of olive oil, its place in society as a prized ingredient is very new. Cultures have previously tried to extract oils from grains and seeds, although the process has always been difficult. The nineteenth century saw the start of using chemical solvents to produce refined vegetable oils and margarines. They gained popularity during the poverty of the Great Depression and rationing of World War II, although people still knew enough to value butter and animal fats. In the ensuing decades, their consumption has been increasing every year, much to the detriment of our health.

Saturated, Monounsaturated, & Polyunsaturated

You’ve probably heard fats or fatty acids described as saturated, monounsaturated, or polyunsaturated. But what does that mean?

The backbone/chain of a fat molecule is made up of carbon atoms with hydrogen atoms on either side. This chain is the center of a saturated fat molecule:

It’s called saturated because all the carbon atoms are saturated with hydrogen atoms on either side. Saturated fats are generally solid at room temperature; picture these structures as building blocks which stack easily on top of each other.

A monounsaturated fat has one spot in the chain where two hydrogens are missing on the same side of the chain, causing their adjoining carbon atoms to form a double bond:

A polyunsaturated fat has multiple places where hydrogens are missing:

A trans fat has missing hydrogens on opposite sides of the carbon chain:

This is often a side effect of the hydrogenation process, which is used to solidify oils by adding hydrogen, for making margarine and similar products. Trans fats are associated with cardiovascular disease, although it’s unclear whether that’s caused by their change in molecular structure, associated with it due to one of many other problems with the fats, like omega-6 fatty acid content, or a little of each.

Fats that are highly saturated are the best of the above, with monounsaturated fats coming in second. Most fats contain a combination of different kinds of fatty acids. Avoid oils with high polyunsaturated content, or those that have been hydrogenated/partially hydrogenated.

Saturated fats have gained an unfair negative reputation. Much of this reputation comes from the fact that saturated animal fats contain cholesterol, although dietary saturated fat intake does not result in high LDL cholesterol (the so-called “bad cholesterol”) in the body. Well-performed intervention trials that reduce saturated fat don’t decrease heart disease or mortality. As we’ve pushed natural saturated fats further off our plates, we’ve lost out. (Check out this database for changes in cholesterol and other fat component intake over the last few decades; we’re eating less cholesterol than we were forty years ago, and obesity and heart disease are still skyrocketing.)

Saturated fats are important for neurological function and energy, and provide important, protective fat-soluble vitamins. Our bodies cannot produce certain saturated fats on their own. We need saturated fat to form tissues in the brain and maintain brain function. Cultures have traditionally sought out saturated fats, especially those from animal sources, and used them liberally. A few common fats with high saturated content are: butter, beef tallow, lard, schmaltz/chicken fat, coconut oil, and unrefined red palm oil. Note that margarines DO NOT count as healthy saturated fats.

After years of trying to promote polyunsaturated fats as a substitute for saturated fats, the health industry is now all about touting monounsaturated fats, which make up about 70% of olive oil’s fat profile. However, a lot of the benefit attributed to largely monounsaturated fats may specifically be about their lower content of omega-6 fatty acids than polyunsaturated fats.

High levels of omega-6 fatty acids, we’re learning, are associated with a striking number of health problems. It’s not surprising; most of them appear in our diet from “foods” that didn’t exist a few generations ago, like highly refined vegetable oil. In omega-6 fatty acids, the first missing hydrogen on the chain is on the sixth carbon atom, which is how they and the other omega-# fats get their names.

Omega-6 fatty acids are associated with problems like impaired thyroid function, obesity, diminished mental health, higher rates of Alzheimer’s, and impaired cognitive development in infants and children. Linoleic acid, an omega-6 fatty acid found in high levels in vegetable oils like sesame, peanut, corn, sunflower (other than high-oleic sunflower), cottonseed, safflower, and walnut, detrimentally affects metabolism, organ function, thyroid and hormone regulation, and is associated with higher rates of certain cancers.

You’ve probably heard more about omega-3 fatty acids than omega-6. (There are also omega-9 fatty acids, the monounsaturated fats found in olive oil, as oleic acid, and canola oil, as erucic acid. Our bodies can produce omega-9 from other fats.) We need very small amounts of omega-6, but it’s pretty near impossible to be deficient in modern society. Omega-3 fatty acids, on the other hand, are extremely protective in a wide range of areas including heart health, cognitive function, mental health, memory, and possibly cancer prevention. We only need a small amount of them, but having the right kind is important.

The most important omega-3 fatty acid is DHA (docosahexaenoic acid), the one found in fish oil. It is not found in plant sources, including vegetable oils or flax seed oil (so please don’t be fooled by the bottles of flaxseed oil for sale next to the cod liver oil and fish oil in the health food store!). Our bodies cannot convert other omega-3s into DHA the way other animals can. However, because of chickens’ ability to do this, we can get DHA from eggs laid by chickens fed flaxseed. Strict vegetarians should be eating these eggs. Vegans cannot get DHA from food.

The body stores omega-6 fatty acids longer than omega-3. They are stored in fats, including the fats in our brains. Maintaining a balanced ratio (high 3, low 6) between the two is important. Because we store omega-6 for longer, higher intake of omega-6 over time builds up. Even more of a reason to bring your omega-6 content down to a bare minimum in order to maintain this ratio.

The bottom line: Avoid oils with high levels of polyunsaturated omega-6 fatty acids. That includes most refined vegetable oils. Prioritize saturated fats and monounsaturated fats. Banish margarine from your life.

Refined and Unrefined

We hear the term “refined” a lot when it comes to modern ingredients. Refined sugar, refined oil, refined palette (oh wait). What does it mean when oil is refined?

Literally, to refine something is to clear out other substances and extract something in its purest form. That in and of itself isn’t a bad concept. Refining generally raises the smoke point of an oil, and therefore makes it better for high heat cooking. The problem is that a few bad things happen during the refining process. For one, the process generally involves some pretty nasty toxins. For another, it can change the molecular structure of the fats, especially when the process involves exposure to high heat that breaks down the fats into detrimental forms.

Refining is also relied on to get oil out of sources that don’t have high oil content. Unlike, say, olives or coconuts, most sources of so-called vegetable oil are not particularly oily. When’s the last time a raw kernel of corn fell on your shirt and left an oil stain? I didn’t think so. But these substances are cheap to produce, and so there’s a financial incentive for making them into oil.

The problem is, that requires some serious processing. The process varies a little from oil to oil, but it looks something like this:

First, the seeds are cleaned to remove trace metals and so forth. Then, they are heated and pressed (this is skipped with some oils). Next, they are treated with chemical solvents like hexane, a cheap and toxic substance which is considered a hazardous air pollutant by the EPA, and is produced by petroleum refineries (getting hungry yet?). Then, the hexane is removed via processes like boiling and evaporation. More high heat exposure, yum.

Next, the oil is refined for flavor and odor, including covering over any nasty taste from the process so far. (I’d just like to stop and ask: why would you want to eat something whose taste had to be masked because it would naturally be too foul to consume?) This is often done by heating the oil and mixing it with substances like lye. Finally, the oil is deodorized at high temperatures and bleached, just in case there’s any bad flavor left over.

Not all refined oils use a high-heat or chemical process. You may have heard of expeller-pressed oil, which uses a mechanical rather than chemical process. Cold-pressing, which is typical for olive oil, avoids exposure to high heat. These are both better than high heat chemical refining processes.

The bottom line: Prioritize simple, natural fats and oils that require little to no refining. Use cold-pressed/expeller pressed oils when their smoke point is suitable. Use refined oils sparingly when needed.

Fat-Soluble Vitamins and Animal Sources

If you’re a regular reader of this blog, you’ve probably heard me mention the importance of fat-soluble vitamins. These are vitamins A, D, K and E. These vitamins are absorbed when ingested with fat, so vitamin A & D enriched skim milk is probably not doing you any good.

Some of these vitamins occur in fats, which is ideal for their absorption. All vitamins occur in various forms, some of which appear in vegetable sources and some in animal sources. Generally, the animal forms are more important for us, and more likely to be missing from our diets.

For example, vitamin K occurs in one form in plants, as vitamin K1 (phylloquinone). Another form, vitamin K2 (menaquinone-7 or MK-7), is found in some fermented foods like natto, among other sources. But the most essential form of vitamin K2, menaquinone 4, is found only in animal fats like grass-fed butter, grass-fed beef tallow, organ meats, and fish organs. We’re still learning about vitamin K2 menaquinone-4, but it’s the substance Weston Price called “Activator X” in his studies, and is essential for brain development, bone health, vitamin absorption, and protective body processes including kidney stone prevention.

Vitamin A as beta carotene is found in a lot of vegetable sources, and is abundant in high-carotene unrefined red palm oil. The form retinol is available in animal sources. If I understand correctly, it seems we can convert carotene to retinol to some extent, but that this depends on our digestive health, and even when healthy we don’t convert all of it.

Vitamin D3 is found in some organ meats and fish organs, in leaf lard, and in cod liver oil, although I don’t recommend cooking with the latter.

Vitamin E deficiency is pretty rare. Olive oil and schmaltz are good sources.

Unlike herbivorous animals, we cannot convert many plant forms of vitamins, including vitamin K, into animal forms. Because of this, I think the consumption of good quality animal fats from animals fed what they’re supposed to eat, is essential. They also happen to make a lot of food taste delicious. A danger of the so-called Mediterranean diet (aside from the fact that it picks and chooses from what people living around the Mediterranean Sea eat), is that relying on olive oil as your only fat means missing out on important fat-soluble vitamins and protective saturated fats.

If you’re vegetarian, your diet should include a lot of butter. If you’re vegan, which I don’t recommend from a nutritional standpoint (although I do understand some of the ethical components), supplement with vitamins D3, K2 menaquinone-4, A retinol. I believe you can find synthetic versions of these, although I’m somewhat skeptical about synthetic vitamins. Take them with plenty of fat, and cook with simple oils like unrefined coconut oil.

The bottom line: It’s ideal to eat unrefined, saturated animal fats from animals raised organically and on pasture.

Smoke Points

The smoke point of an oil is the temperature at which it starts producing smoke. You want to avoid letting oil reach this point for several reasons. On the lesser side, you’ll set off the smoke detectors, make your kitchen smell terrible, and make your pans hard to clean. But more importantly, when an oil crosses its smoke point, the fats begin to break down and oxidize, changing the molecular structure and producing detrimental free radicals. In the chart at the end of this post, you’ll see smoke points for many common cooking fats and oils.

Flavor

We eat because food tastes good, right? The flavor of the oil or fat you use matters. You want it to balance, enhance, or take a back seat to the flavors in your food. Certain oils simply taste wrong with certain foods. Olive oil doesn’t go with Thai food. Red palm oil tastes terrible with eggs. Refined vegetable oil doesn’t give any flavor to baked goods, and leaves them tasting dull. Beef tallow would overpower sautéed fruit.

People often turn to vegetable oils because their flavor is neutral, thanks to all that bleaching and deodorizing. That’s a benefit in some cases, but you can often find another oil or fat that works well for the dish you’re making. My favorite example: I like using unrefined coconut oil in Thai food, whereas vegetable oils are commonly used. Coconut is a flavor found throughout Thai cooking, so it goes fairly well. Check out this recipe for basil chicken and basil chicken fried rice as an example.

Pesticides

As with most foods, organic oils are a safer bet than non-organic ones. Pesticides have been found in vegetable oils, like soybean, peanut, and sesame.

However, the worst culprit is cottonseed oil. A large fraction of the pesticides sprayed in the United States are used on the cotton crop, including some pretty toxic chemicals. Cotton is not grown primarily as a food crop. I’m finding older reports that suggest none of the regulations that apply to pesticide use on food crops apply to cotton, and I’ve yet to find anything more recent that contradicts this information. As usual, please send me any updates you have.

But even aside from horrific pesticide residue, cottonseed oil is one to avoid, with high polyunsaturated fatty acid content and significant refining. It’s cheap to produce, so you see it in a lot of processed food and baked goods. But don’t you want to eat food that’s made of... food?

The bottom line: Buy organic oils and never buy cottonseed oil.

Basic Charts of Oils and Fats

You can find some of the sources I compiled for my chart below here, here, here and here.

I’ve highlighted some of my favorites in green, mediocre oils in yellow, pretty bad oils in orange, and ones to avoid completely in red. I included omega 6:3 ratio in order to illustrate extent of omega-6 content, not because you should seek out omega-3s in vegetable oils.

If you can’t see this chart in your RSS feed, click here. (If you can’t see it on the web page, send me an email. I’ll try to fix it.)

A few notes about the chart:

-Leaf lard and beef suet both have even better omega 6:3 ratios (i.e.: lower 6) when the animals are raised on pasture.
-All the figures above vary to some degree, but these numbers give you a general sense