Safe & Healthy Cooking Oils
Dr. Bruce Fife a.k.a. “Dr. Coconut” answers often asked questions about coconut oil.
I often see the iodine value mentioned when describing the properties of oil, including coconut oil. What does this mean?
Most people don’t understand this term and mistakenly believe it represents the iodine content of the oil. It has nothing to do with iodine content. Processed oils don’t have any iodine. The iodine value is a measure of the degree of the unsaturation of an oil. Technically it is the value of the amount of iodine, measured in grams, absorbed by 100 ml of a given oil. Although the iodine value may sound uninteresting, it has some very important health implications.
All fats and oils are composed of fat molecules known as fatty acids. The molecules can be classified into three categories depending on their degree of saturation. You have saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids.
No oil in nature is composed entirely of any one of these three. All dietary oils contain a mixture. Soybean oil, for example, is referred to as a polyunsaturated oil because that is the predominant fatty acid. It also contains 24 percent monounsaturated fatty acids and 15 percent saturated fatty acids. Coconut oil is also a mixture. It contains 92 percent saturated fatty acids, 6 percent monounsaturated fatty acids, and 2 percent polyunsaturated fatty acids.
The terms saturated, monounsaturated, and polyunsaturated refer the degree of hydrogen saturation. A saturated fatty acid contains all the hydrogen atoms it possibly can. In other words, it is fully saturated with hydrogen. A monounsaturated fatty acid contains all but one pair of hydrogen atoms it can hold. A polyunsaturated fatty acids is lacking two or more pairs of hydrogen atoms.
The iodine value is a measure of the amount of unsaturated fatty acids in the oil. A fatty acid that is missing any hydrogen atoms is classified as being unsaturated. This includes all monounsaturated and polyunsaturated fatty acids.
Although the iodine value is used primarily in industry, it is of value to us because it gives an indication of the oil’s stability and health properties. Coconut oil has an iodine value of 10. This indicates that it contains a high amount of saturated fatty acids and a very small amount of unsaturated fatty acids. The higher the iodine value, the greater amount of unsaturation. As noted above, coconut oil is 92 percent saturated and 8 percent unsaturated. Soybean oil, in contrast, has an iodine value of 130. It contains only 15 percent saturated fatty acids with 85 percent unsaturated fatty acids, thus the reason for its high iodine value.
The higher the iodine value, the less stable the oil and the more vulnerable it is to oxidation and free radical production. High iodine value oils are prone to oxidation and polymerization. During heating, such as when used in cooking, oils with a high iodine value readily oxidize and polymerize. Polymerization is an irreversible process which causes the fatty acids to become hard, insoluble, plastic-like solids.
Because of their tendency to harden when oxidized, polyunsaturated vegetables have been used extensively as bases for paints and varnishes. You can see this effect in the kitchen. When you use polyunsaturated vegetable oils in cooking sometimes the oil spills onto the outside of the pan. If the outside of the pan is not thoroughly cleaned, over time you will notice a buildup of a very hard, amber colored, varnish-like substance on the bottom of your fry pans.
This is polymerized vegetable oil. The oil you used in cooking has literally turned into varnish. It takes a scouring pad and a lot of elbow grease to scrub it off the pan. When high iodine value oils are heated, you are creating polymerized fatty acids in your food. The higher the temperature or the longer the exposure to heat, the greater the degree of polymerization.
These products of oxidation have been shown to be associated with numerous health problems including cancer and atherosclerosis (hardening of the arteries).
Coconut oil has the lowest iodine value of any dietary oil. Therefore, it is very resistant to oxidation and polymerization. It makes a very safe cooking oil.
Iodine Values of Some Common Oils:
- Coconut Oil 10
- Palm Kernel Oil 37
- Beef Tallow 40
- Palm Oil 54
- Olive Oil 81
- Peanut Oil 93
- Canola Oil 98
- Sunflower Oil 125
- Soybean Oil 130
Above are the iodine values of some common oils. Personally, I wouldn’t cook with any oil that has an iodine value over 80. ■
More information on why coconut oil is so healthy -click here
Healthy vs Unhealthy (the truth may surprise you!)
Some of these oils are healthy and some are VERY unhealthy -- soybean oil, olive oil, coconut oil, corn oil, etc... Let's take a closer look.
by Mike Geary, Certified Nutrition Specialist, Certified Personal Trainer
Author of best-selling program: The Truth about Six-Pack Abs
Today, I wanted to give you my take on a confusing subject to most people:
...why some oils and fats you may use in cooking, baking, or other food use are actually harmful to your body, and why some are healthful.
Here's the deal...
A lot of people seem to think that anything labeled as "vegetable oil" is good for you. NOT A SHOT!
Most of what is labeled as "vegetable oil" is simply heavily refined soybean oil (processed under high heat, pressure, and industrial solvents, such as hexane)... sometimes perhaps it may also be heavily refined cottonseed, safflower, corn, grapeseed, or other oils too.
In most instances, almost all of these processed oils are NOT HEALTHY for you. I'll explain why below...
If you buy processed food or deep fried food, you can usually be certain that these unhealthy oils are used to prepare your foods (or worse, it may use hydrogenated versions of these oils... aka - trans fats).
You may have even bought some of these oils for your own cooking or baking at home.
The problem with soybean oil, cottonseed oil, corn oil, grapeseed oil, safflower oil, and other similar oils is that they are mostly composed of polyunsaturated fats (the most highly reactive type of fat) which leaves them prone to oxidation and free radical production when exposed to heat and light.
Processed polyunsaturated oils are the most inflammatory inside our bodies because of their high reactivity to heat and light. This inflammation is what causes many of our internal problems such as heart disease, diabetes, and other degenerative diseases.
Note: It's ok if a polyunsaturated fat source isn't processed such as in whole foods like various nuts and seeds... In that case it's usually not inflammatory (as long as it's not been exposed to high heat), and is a great source of healthy polyunsaturated fats for you. By the way, omega-6 and omega-3 fatty acids are both polyunsaturates, and a healthy balance of approx 1:1 to 3:1 ratio of omega-6 to omega-3 is considered healthiest. Your best bet is to choose raw nuts and seeds whenever possible to avoid the oxidation of polyunsaturated fats that can occur during roasting of nuts and seeds. Keep in mind though that some nuts are mostly monounsaturated, (for example, macadamias), so the issue of roasted vs raw nuts is less of an issue for highly monounsaturated nuts.
However, all of the vegetable oils listed above are generally heavily refined during processing, so that makes them already inflammatory before you even cook with them (which does even more damage).
Here's the actual order of stability of a type of fat under heat and light (from least stable to most stable):
Here's something that mainstream health professionals will never tell you...
Saturated fats are actually the healthiest oils to cook with!
Why? Because they are much more stable and less inflammatory than polyunsaturated oils.
This is why tropical oils such as palm and coconut oils (and even animal fats such as butter) are best for cooking... they have very little polyunsaturates and are mostly composed of natural saturated fats which are the least reactive to heat/light and therefore the least inflammatory in your body from cooking use.
That's also why natural butter (NOT margarine) is one of the best fats for cooking. This all goes directly against what you hear in mainstream health talk... because most health professionals don't truly understand the biochemistry of fats, and falsely believe that saturated fats are bad for you... when in fact, they are actually neutral in most instances... and saturated fats from tropical oils are actually good for you as they contain mostly medium chain triglycerides (MCTs) which are lacking in most people's diets.
In fact, lauric acid is one of the abundant MCTs in tropical oils and is known to strengthen the immune system. Lauric acid is even being studied currently in medical studies for controlling contagious diseases.
To summarize... your best cooking or baking fats are generally butter or tropical oils such as palm or coconut oil. Olive oil (extra virgin preferably) is ok for lower cooking temps as it's mostly monounsaturated, so moderately stable. The mostly polyunsaturated oils such as soybean, grapeseed, cottonseed, safflower, etc, are the least healthy for cooking or baking.
My choices for top healthy cooking oils that I use:
- Virgin Coconut Oil
- Extra Virgin Olive Oil (only for low temp cooking)
- Real Butter (grass fed if possible)
Also, please don't be fooled by deceptive marketing claiming that canola oil is healthy for you -- it's NOT!