FATS...What were we thinking?
Fats are one of the most OVERWHELMING topics in nutrition. Last week I taught a class on FATS and could see the confusion in the audiences eyes. This is a little long, but there's still SO much more that I could have included.
When some people explain to me that they “eat healthy,” their explanation usually involves something about not eating “a lot of fat.” They just use egg whites, only eat chicken, cook with "good" oils and NEVER would they eat butter (how dare I even suggest such a thing).
Many of these people have some sort of negative reaction when they hear about a food that’s high in fat (even if it’s good for them). I mean really, even an avocado scares some people. Limiting an avocado because of fat? We have some major work to do in the way of educating people about this wonderful macronutrient that has been given a bad rep. Don’t stop here and go get ice cream and french fries- read through so you know what fats are keepers and which need to be THROWN IN THE TRASH.
Why do we need it? Just to start, some fats are essential. This means that our body cannot produce them and they MUST be in our diet- otherwise bad things can happen. We also need fats to absorb fat soluble vitamins (A, D, E & K), produce some hormones (yup, some hormones are made from fats) and support brain function (our “thinker” is over 65% fat). One of the most important reasons why we want some fat on our plate, in my opinion, is to maintain proper CELLULAR FUNCTION.
The outside of EVERY CELL IN YOUR BODY is surrounded by fat (for those of you that care it’s called a phospholipid membrane).
It’s the boss of what gets in and out of your cell- energy, minerals, fluid, nutrients, etc. Most people want (and NEED) this membrane to work well and do its job. I mean if it’s not, you’re kind of in trouble (even if you don’t realize it).
Just as there are benefits to obtaining adequate healthy fats, there are also some DANGERS to consuming what we will call OXIDIZED/RANCID fatty acids. This is where things start to get confusing. Consuming oxidized or “bad” fats can ALTER cellular function (1), cause free radical damage (2- scroll to the lipid peroxidation section), increase your risk for cardiovascular disease (3, 4) and promote an inflammatory response (5).
So how do you know which is which?
Read ahead with caution, you are about to be very disappointed with our food supply- but we’ll work through it.
To start- the major type of fat, both in your food and in your body, is called a triglyceride. They look like this:
Triglycerides can be either SATURATED or UNSATURATED, depending on those long fatty acid tails.
A saturated fatty acid looks like this, “saturated” in hydrogen.
See how all the lines are single lines when you look at the "long chain" part? They have no “double bonds.” Think back to chemistry (I know, I know, not good), remember how stable those single bonds are? They are so stable, it’s difficult to “break” them. This is the basis of why we want to heat/cook with saturated fats, the single bonds can tolerate a lot before they “break.” They are typically solid at room temperature- think coconut oil, butter and ghee.
Some people associate these saturated fats as artery clogging bad guys and run far away from them, no matter the situation. Recently they have been looked at in a new spot light, in fact several large studies have shown that they DON’T HAVE THE ASSOCIATION WITH HEART DISEASE we once thought (6, 7, and 8). In fact, some studies have shown the positive effects of this fat, including increasing HDL sometimes (9 and 10). When we cook with a saturated fat it doesn't become oxidized or rancid, eliminating the risk for additional free radicals. We know that free radical damage has been linked to cancer, heart disease, diabetes and more- so we WANT to reduce the risk for free radical damage any way we can.
Another fun fact, HALF of that cell membrane is composed of saturated fatty acids.
First thing to remember: When cooking use natural saturated fats (solid at room temperature)- coconut oil, butter and ghee. Remember I'm talking about how they are safe to cook with; I am NOT promoting the consumption of fried and processed foods high in saturated fats- these foods often do not use a natural occurring saturated fat (we will get to those oils later).
An unsaturated fatty acid looks like this:
or like this...
It can be either monounsaturated (ONE double bond) or polyunsaturated (SEVERAL double bonds). Think back again….double bonds are NOT stable (they are reactive, they have a lot of "energy"), they can break very easily- especially when exposed to heat. When these bonds are broken, the fatty acid can then be “oxidized.” It can create free radical damage, accelerating a vicious chain reaction (more info 11). AHHHHHHH what?! Remember free radical damage….cancer, heart disease, etc.
Unsaturated fatty acids are typically liquid at room temperature, the more double bonds they have the more reactive (unstable) they are.
Let’s look at the two types….
Monounsaturated fatty acids are relatively stable; remember they just have ONE double bond. They can be manufactured easily, with NO heat and minimal chemicals. Think of olives and avocados- these are oily foods; the oil can be extracted fairly easily. They are often “cold pressed,” meaning that they were not exposed to heat during processing. This is GREAT news! It means that as long as you don’t heat them up at home the double bonds are still intact and the oil is not oxidized or rancid yet. Some research shows that monounsaturated fats can be heated up slightly, but I would be extremely careful with this.
Second thing to remember: Put olive oil or avocado oil on your foods after they are cooked; pour on salads, cooked pasta, etc. DO NOT HEAT THEM UP. Keep them in a cool, dark place where they are not exposed to heat and light.
Polyunsaturated fatty acids are a different story. They have several double bonds, making them very “reactive” and prone to oxidation. They are easily oxidized when exposed to heat, light and oxygen. These were almost NON-EXISTENT in our diet until the early 1900's when chemical processes allowed them to be extracted.
We do need a small amount of polyunsaturated fatty acids, a SMALL amount. Most of us are consuming TOO much….and most of them are rancid and oxidized.
Typical sources of polyunsaturated fats: corn oil, vegetable oil, soybean oil, rice bran oil, etc. MOST of the liquid oils down the aisle at the grocery store fall under this category.
So remember, because of all the double bonds we don’t want to heat up these oils because they are SO reactive and easily damaged. So does that mean we can buy them and just not heat them up? NOOOO.
Think of a piece of corn. When you take a bit do you think, “Oh, these corn kernels are so rich in oil.” NO. That’s because corn isn’t naturally high in oil (like the olives and avocados)- so how the heck do they make all that corn oil? With A TON OF HEAT, PROCESSING AND CHEMICALS. It takes a lot of work to get that oil from corn (and most of those other polyunsaturated oils).
When they make these oils they HEAT them up (free radicals anyone?) and use chemicals (like Hexane, 12) to extract the desired product. Usually they smell bad at this point (because they have oxidized and are probably rancid), so they deodorize them. Corn, canola or soybean oil anyone???
My point is that these oils are probably already rancid when you purchase them. Not only are they heated prior to packaging, but usually their packaging is a CLEAR plastic bottle (light also promotes fatty acid oxidation).
Here's an interesting video about how canola oil (one the most heavily advertised oils) is made...(I would ignore the propaganda in the first minute about it being "healthy.") Pay attention to the heating, pressing, chemicals and toxic solvents that are used during production.
Some recent research has shown that vegetable oils may increase your risk for heart disease, even when they lower cholesterol short term (13). In fact, a while ago they looked at fatty acids found in clogged arteries. They found that they are mostly unsaturated fatty acids, 74%, of which 41% are polyunsaturated (14). This is all being looked at more often now, some research suggests the types of fats may not have as large as an impact as we once thought on our cardiovascular system; but they are definitely questioning the high consumption of polyunsaturated fatty acids (15).
The one thing WE CAN ALL AGREE ON are the elimination of trans fatty acids. Remember a few months ago the FDA announced that it was considering banning them from the food supply (16)? One study looked at common vegetable oils on food shelves in the U.S. market and discovered that they contain between 0.56 to 4.2% TRANS FATS (17)!!! This is due to the manufacturing process of these oils and WILL NOT BE ON THE LABEL. If there is a single reason why you should stay away from these oils- THIS IS IT!
I know these oils are cheaper than what I'm recommending; keep in mind that corn and soy are two of the largest agricultural government subsidies. Billions of tax dollars are used to subsidize these commodities; this keeps them cheap and appealing for large food manufacturers to use. This is an entire different blog post though...
Third thing to remember: stay away from highly processed polyunsaturated oils. Think of corn, soybean, canola, rice bran, sesame, etc. Don't eat things that have been cooked with these oils (think fried foods along with packaged and processed foods- look at the ingredient label).
Last thing I promise…let’s talk about the polyunsaturated fatty acids that you do need.
Omega-3 and Omega-6 are your essential fatty acids (the ones your body cannot produce on its own). They are needed for proper cellular function, blood clotting, blood pressure, the regulation of inflammation and more pretty important stuff.
Most people get far TOO MUCH Omega-6, and not enough Omega-3. Good sources of Omega-3 are fatty fish, flax seed oil (kept cold in a dark container- never heated), raw nuts and seeds, etc. Most people need to focus on getting more Omega-3 in their diet; when we get too much Omega-6 with a much lower amount of Omega-3 it can lead to an increased inflammatory response (18, 19, 20) and other concerns. Typically it’s recommended that we consume Omega-6 to Omega-3 in about a 3:1 ratio (21)- most people are consuming them at a 16:1 ratio (22). WE NEEEEEED TO WORK ON THIS!!!
I’d like to bring up grass fed meat and dairy products for a moment. The major difference between grass fed vs grain fed is the omega content. Grain fed cows result in foods that are HIGH IN OMEGA-6 and have almost NO OMEGA-3. You can see below that as cows are fed a grain based diet their essential fatty acid content is depleted.
Grass fed cows produce foods that are HIGH IN OMEGA-3 and have a much better ratio to the Omega-6 fatty acids. So choose GRASS FED whenever it’s possible!!!
Fourth thing to remember: focus on Omega-3 fatty acids. Get in wild caught fish, raw nuts and seeds, grass fed meat and dairy products, etc.
Let’s recap quickly! What should you do now?
Make sure you’re getting enough of the GOOD STUFF:
- Cook with coconut oil, butter, ghee (natural occurring saturated fatty acids)
- Use olive oil/avocado oil on “ready to eat” foods- don't be shy!
- Focus on getting Omega-3 fatty acids
- Store your oils in a cool, dark place
- Purchase grass fed/organic products when possible (meats, dairy and butter)
- Eat LESS packaged/processed foods
Make sure you’re staying away from the BAD STUFF:
- Avoid polyunsaturated oils that have been heated/processed (corn, canola, soy, etc)
- Do not heat oils that should not be heated
- LOOK for trans fats, but also be aware of where they may be hiding
- Stay away from fried foods and other products that have been cooked in processed oils
- Read labels and see what type of oils are in your packaged food products (unfortunately you will be disappointed)
- Eat LESS packaged/processed foods
“Nature doesn’t make bad fats, factories do.”
–Dr. Cate Shanaham
Another one of my favorites when looking at oxidized lipids...
"These studies have shown, for the first time, that degradation of lipids in foods can produce toxic oxygenated aldehydes. These compounds, well-known in medical studies for their geno- and cytotoxic activity, considered as markers of oxidative stress in cells as well as being causal agents of degenerative illnesses, had not previously been detected in foodstuffs. Researchers have shown that some oils produce these toxic substances in greater quantities and at a greater rate."