The “Skinny” on Fats

INTRODUCTION:

Many people believe that saturated fat is “bad” for you but few people realize that our bodies actually manufacture it.  It’s true. In this article, I cover “just enough” chemistry (made very easy!!) for you to be able to understand the latest new findings. My next article will be on a change in the dietary recommendations of a key stakeholder in heart health in Canada, and what this change means.

If Saturated Fat was so Dangerous, Why Would our Body Actually Make it?

There are two sources of fats (also called “lipids“); those we eat in our diets and those our body makes. The fats we eat are called “exogenous fats” (“exo” meaning ‘from outside’) and the type of fats that our body makes are called “endogenous fats” (“endo” meaning ‘from within’).

Exogenous Fats

The types of fat that our body takes in as exogenous lipids from what we eat include saturated fats, and different kinds of unsaturated fats — including polyunsaturated fats — both omega 3 and omega 6, as well as monounsaturated fats. You can look back to the preceding blog, if you aren’t clear on these.

Endogenous Fats

Our body actually makes fat in a process called lipogenesis. This is important because some of the LDL cholesterol and triglycerides (TG) that gets reported on blood test results is endogenous; that is, our bodies made it. So we have high LDL (“bad” cholesterol) or triglycerides it’s not all from the fat we eat!

[Not only do our bodies make saturated fat, but excess carbohydrates gets stored in our body first as triglyceride and then if it still isnt needed, it gets stored as LDL cholesterol in our liver.  So carbs can raise both triglycerides and LDL cholesterol.]

Below, I will present just enough chemistry to understand the different types of fat and more importantly, be able to read about them and understand.

The Saturated Fat Our Body Makes and What it is Used For

1. The first thing that you need to know is that palmitic acid is a long-chain saturated fat is made (synthesized) in the liver. Palmitic acid is a 16-carbon fatty acid and having so many carbons in its backbone, it is considered “long chain”). It has no double bonds, so all the carbons in the backbone have a hydrogen bound to it (more on that below), so palmitic acid is a saturated fat.  Palmitic acid is found naturally in foods such as butter, cheese, milk and meat — but it is also synthesized by our bodies!

Now the message of the media since the mid- to late-1970s is to eat low-fat dairy; including low fat milk, low-fat yogourt and low-fat cheese with the assumption that saturated fat is “bad” for us — but our bodies actually manufacture it!

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2. The other thing that you need to know is that a triglyceride is made up of three fatty acids attached to a glycerol molecule. That’s easy to remember, because “tri” means “3”.

a) Glycerol acts as the support for the other fats and is made up of three carbon atoms, each with something called a “hydroxyl group” bound to it.

A hydroxyl group (written “-OH”) is an oxygen and a hydrogen molecule bound together.  That is, water (H2O) is just a hydrogen (H) molecule bound to a hydroxyl (-OH) group.

So, this is a glycerol molecule;

As you can see, each of the carbons in the chain have a hydroxyl (-OH) group bound to it. Easy, so far, right?

b) Fatty acids are long chains of carbon atoms (i.e. think of a freight train, where each rail car is a carbon atom) with a carboxylic acid (-COOH) group at one end (i.e. the caboose is a carboxylic group). At each of the carbons in the chain, there is the potential for a hydrogen atom (H) to bind there.

You may recall from our previous article that a saturated fat is one that has no double bonds in the carbon chain, so in that case, all the carbon atoms in the chain have a hydrogen attached.  It is having all the carbons “saturated” with hydrogen atoms, that make it a “saturated” fat!

The names given to fatty acids are based on the number of carbon atoms and the number of carbon-carbon double bonds in the chain.

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Different Kinds of Oils 

Remember, a triglyceride is made up of three fatty acids attached to a glycerol molecule. So, for example, palmitic acid and stearic acid are both exactly the same, except one has 16 carbons (palmitic acid) and the other has 18 carbons (stearic acid) in its chain.

Palmitic acid, a saturated fat has 16 carbons.  That is, it is “saturated” with hydrogen atoms at each of its 16 carbons. It is all of this “saturation” that makes saturated fat solid at room temperature.

Stearic Acid, is also a saturated fat, but has 18 carbons, so each of its carbons has a hydrogen bound to it,

Using just these two saturated fatty acids (palmitic acid and stearic acid) we can combine them in different ratios to make entirely different oils! For example, canola oil has a 4:2 ratio of palmitic acid to stearic acid and grapeseed oil has an 8:4 ratio of palmitic acid to stearic acid.

Furthermore, the same two fatty acids can be put together in the same ratio and be different fats. For example in a 7:2 ratio, it could be either almond oil or safflower oil — depending on how they are put together.

Palmitic acid, the saturated fat that our body makes is found in all kinds of “healthy” foods.

Lipogenesis – Our Bodies Making fat!

Lipogenesis is the process by which our bodies actually make fat and our bodies can make unsaturated fats or saturated fats.  

Unsaturated fatty acid lipogenesis

Our body can make a longer chain unsaturated fat from a shorter chain fatty acid (such as taking the linolenic acid from flax seed and adding carbons to the chain to make arachidonic acid). But there are limits.  Our bodies cannot take the linolenic acid from flax seed and make it into eicohexanoic acid or decahexanoic acid which are the healthy “omega 3 fats” fats found in  fish. So eating eggs made from chickens fed flax is not the same as eating fish.  We just can’t turn one into the other. Our body can make it longer, but not much longer.

Saturated fatty acid lipogenesis

As said above, our bodies synthesize palmitic acid, a 16 carbon saturated fat in our liver and then forms a triglyceride from three palmitic acid molecules attached to a glycerol molecule. These triglycerides are then transported around the body in something called a VLDL. More on that just below. 

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Cholesterol – The Good the Bad and the Ugly

Most people know that HDL cholesterol is the so-called “good cholesterol” and LDL cholesterol is the “bad” cholesterol  — but where does LDL (“bad cholesterol”) come from? The first step when our body makes something called VLDL.

Very Low Density Lipoproteins (VLDL)

The body takes the triglycerides it manufactures in lipogenesis as well as takes in in the diet into Very-low-density lipoprotein (VLDL) cholesterol. These VLDLs move cholesterol, triglycerides and other lipids (fats) around the body.

VLDL is produced in the liver and include the triglycerides made with differing amounts of palmitic acid.  That is, our bodies MAKE palmitic acid in the liver and then combine the palmitic acid it makes in differing ratios, into triglycerides. It then takes the triglycerides, containing palmitic acid and protein and packages it into VLDLs. It then releases the VLDLs into the bloodstream, to supply body tissues with triglycerides.  About half of a VLDL cholesterol is made up of triglycerides, including those containing the palmitic acid it made!

High levels of VLDL cholesterol have been associated with the development of plaque deposits on artery walls, which narrow the passage and restrict blood flow.

VLDL cholesterol on blood test results aren’t measured, but estimated as a percentage of the triglyceride value.

What is LDL cholesterol?

When VLDL cholesterol reach fat cells (called “adipose tissue”), the triglyceride is stripped out and absorbed into fat cells. That means that VLDLs shrink.

Once a VLDL has lost a large amount of triglyceride it becomes a new, smaller, lipoprotein, which is called Low Density Lipoprotein, or LDL — the so-called bad cholesterol’. LDL contains mostly cholesterol and some protein. Some LDLs are removed from the circulation by cells around the body that need the cholesterol contained in them and the rest is taken out of the circulation by the liver.

Here is the key point: the only source of LDL is VLDL. 

Saturated Fat — not dangerous and can be beneficial 

The media keeps telling us that “saturated fat is bad” and that it is even “dangerous” — but if it was so dangerous, why would our bodies actually manufacture it?  Our bodies manufacture palmitic acid, a saturated fat, then synthesize triglycerides from it which it sends all around our bodies, supplying our bodies with saturated fat!

Furthermore, there are some saturated fatty acids, called Medium Chain Triglycerides (MCTs) that are metabolized entirely differently than the longer chain saturated fatty acids and have beneficial properties.  These MCT oils go straight to the liver by the portal circulation and don’t need to be digested.

People who consume fats high in MCT oil, such as coconut oil which is almost half (44-55%) Lauric acid, an MCT have been found to have lower amounts of “belly fat” than those that do not consume these saturated fats.  Studies have found lower rates of ”visceral adiposity” or ”belly fat” in those that consume these fats, and correspondingly , lower lowering waist circumference.

Since carrying fat around the abdomen (the so-called “apple shaped” people) is considered to be a risk-factor to heart disease and studies have found that those who eat a diet high in MCT saturated fats have less fat around their middles and a smaller waist circumference, can we categorically say that saturated fat is really “bad” or “dangerous” to heart health. In fact, in our next article, we will outline the beginning of a change in the recommendations concerning saturated fat consumption.

Some thoughts…

Saturated fat and its consumption needs to be put into context; one context would be looking at the risks of a high carbohydrate diet compared with a high saturated fat diet, for example.  As covered in previous blogs, prior to 1977, when the dietary recommendations in Canada and the US changed to favour a diet low in saturated fat and high in carbohydrates, the rate of Diabetes was 1/10th what it is now and obesity rates in adults, especially men were too. Childhood obesity was almost unheard of prior to 1977.

Another context would be to differentiate between saturate fats.  That is, to look at which saturated fats.  Numerous studies demonstrate the benefits of MCT oils in increasing metabolism, lowering body fat, especially “visceral adiposity”.

Another context would be to determine how much of the “high cholesterol” (i.e. high LDL cholesterol) came from VLDL that was endogenously produced, versus eaten (exogenous).

Many studies have found that people are less hungry (have increased “satiety”) when they consume higher fat dairy products (which are rich in saturated fat), and as a result consume less calories overall than those that do not eat higher fat dairy products. So, we need to know which fats, and in particular which saturated fats are associated with this increased satiety?

It is my opinion that “vilifying” fat — labelling it as ‘unhealthy’ and the current government dietary recommendations and the media ads encouraging us to eat “low fat” everything, is creating a much bigger problem than the fat itself.  When manufacturers take out fat, they have to ‘replace” it with something and that ‘something’ is often sugar (simple carbohydrates).  Is increasing the carbohydrate content ‘safer’ than the naturally occurring fat that was found in the milk or yogourt or cheese, in the first place?

Recent studies seem to indicate that saturated fat consumption is not the issue when it comes to heart risk — and that saturated fat may actually be protective against heart risk. Certainly there are many studies showing the benefits of consuming MCT oil for reducing “belly fat”, which reduces heart risk — so can we say that something like coconut oil, used in moderation is “bad” or “dangerous”.

Looking at the epidemiological data from the last 35 years, we can see what has happened to obesity rates and diabetes rates since both the American and Canadian governments have been encouraging us to eat “low fat” everything.

Are naturally occurring fats really the issue — or are synthetic “trans fats” and excess carbohydrate?

At this point in time, I am persuaded by the many studies I have read, that naturally occurring fats, including saturated fat are not “bad” or “dangerous” when consumed as part of a whole-foods diet.

Note: Everyone’s results following a LCHF lifestyle will differ as there is no one-size-fits-all approach and everybody’s nutritional needs and health status is different. If you want to adopt this kind of lifestyle, please discuss it with your doctor, first.

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