Dietary Cholesterol: What is it and is it bad for you?

For over 50 years we have been told that Dietary Cholesterol causes heart disease and that the saturated fat in our diets containing dietary cholesterol should be avoided in order to maintain a healthy heart. At the time of the early research there was reason to suspect this was indeed the case but given that science has moved a lot over the past 50 years does the latest research still hold with this hypothesis?  
Is Dietary cholesterol a driving factor of heart disease, and if so how much of factor is it?

What is Cholesterol

Most people when they hear the word cholesterol think only of it as a sticky waxy type of substance that clogs up our arteries and causes heart disease and never realise just how important cholesterol is to the human body.
For example, the walls of every cell in your body, all 37 trillion of them (yes that is a rather huge number) are made mostly from fat and half of all the molecules that make up every one of these cells is cholesterol. Cholesterols job in the cell membrane is to make the cell supple enough for nutrients to be able to pass through it and to aid in the singling between the inside and the outside of the cell. [1]
Many of your hormones are made from cholesterol, including your sex hormones, Oestrogen and testosterone. It is also a fundamental building block of Vitamin D, which is a major part of your immune system.
In other words, without cholesterol you would not survive…

HDL, LDL and VLDL, The Good the Bad and the downright dirty.

Most of the time when people refer to their cholesterol levels they are in fact referring to the lipoproteins inlipoproteins their blood, HDL, LDL and in some cases VLDL. These 3 mysterious abbreviations stand for High Density Lipoproteins, Low Density Lipoproteins and Very Low Density Lipoproteins.

Lipoprotein’s are little balls of cholesterol wrapped in protein. The reason the cholesterol is wrapped in protein is because our blood is a water based substance and cholesterol is a fat and as you know fats and water don’t mix, so our bodies coat the fats in proteins so that they can be transported around our bodies to wherever they can be best used. The adage of High, Low and Very Low, simply refers to how much fat relative to protein there is in these little transportation balls.  So VLDL have more fat and less protein than LDL and LDL has more fat and less protein than HDL. [2]
The different lipoproteins also function in different ways, as we will now see.


When it comes to heart disease these two are the ones that most people look at and while it is certainly true that the LDL family of lipoprotein's are a signaller for a greater chance of heart disease, it is that you have LDL in your blood, (which is perfectly normal), that is the problem, it is the amount of them in your blood that can be the problem.  To be even more accurate it is the proportion of LDL to HDL that really matters. As long as the amount of HDL in your blood is greater than the LDL, the overall amount of LDL you have is not so important.
People with more of the VLDL have been shown to have even higher than average risks of heart disease also. [3]


HDL is often referred to as the “Good Cholesterol,” and this is because HDL’s job is to cruise around in your blood collecting cholesterol which it then brings to your liver where it can be used or stored.
High levels of HDL have been shown to be a signaller of a low risk of heart disease and have been shown to reduce plaque build-up in the arteries. [4]
Again, when looking at your blood results it is the ratio of HDL to LDL that is far more important the overall cholesterol count.

Dietary Cholesterol

steak2_copyAnother aspect of cholesterol that most people miss is the fact that our own body’s make the stuff. Yes, we digest some cholesterol in our food but the majority of our cholesterol is made in our livers. In fact, if we eat too little cholesterol our livers simple ramp up their production of it and if we eat a lot of it, our livers simply lower the amount they make. [5]
Cholesterol it seems is just too important a substance for our bodies to leave to our dietary habits.
However, there are some people out there, about 20% of you who are what are referred to as “Hyper responders,” [6] people whose blood levels of cholesterol really do go up quite a bit when they eat a high cholesterol diet. Again, this can often cause panic when a hyper responder sees a blood cholesterol result. But high blood cholesterol does not seem to be an indicator of heart disease in and of itself. Most to the increase in cholesterol is the larger safer versions of the LDL and also the HDL, which counter act any possibly negative effects by some of the LDLs in most people.  Hyper responding seems to be a genetic trait.
It should be worth nothing that while most hyper responders have nothing to worry about, a small percentage of people certainly do show an increased risk of heart disease with an increase in blood serum cholesterol but this is not as common as most people believe.

Dietary Cholesterol and the risks to heart disease.

 As we have seen above dietary cholesterol has very little to do with heart disease but other factors can contribute a lot to the disease. Smoking, Inflammation, high blood pressure and oxidative stress probably all contribute more to heat disease than high cholesterol levels.

Inflammation and heart disease

Inflammation is a great example to use to show how heart disease occurs because it also answers one inflamation12question that comes up when people are faced with the idea that cholesterol may not be the heart disease culprit that we first believed it to be; namely, if heart disease is not caused by cholesterol then why do we see a lot of it in the arteries of people suffering with heart disease?
One of the possible reasons is as follows.
When our arteries become inflamed (often caused by continuous mental or physiological stress, such as might be experienced by having a high stress job or a poor diet filled with sugars, processed carbohydrates and trans fats, or even worse…both) it causes tiny cracks in the lining of the arteries. The bodies response to this is to seal over this cracks with cholesterol and then when the injury heals the cholesterol simply dissolves away. However, if the stress or diet is chronic, (lasting decade after decade), then the cracks never heal and the cholesterol plaster slowly hardens into a plaque. What’s worse is that over these decades more and more inflammation occurs and more and more cracks appear and more and more cholesterol plasters are laid down and so more and more plaque builds up, blocking the arteries and eventually causing heart disease. [7]
So, you see, it was the inflammation and not the cholesterol that was the problem. Reducing cholesterol in your diet will not help this problem, except perhaps in the most sever hyper responders, because even if you eliminate all the cholesterol from your diet, your liver will keep making more of it to plaster up all the damage you are doing to your arteries. Fix the inflammation though and the cholesterol build up in the arteries will slowly fix itself. No more inflammation then no more need for cholesterol plasters and so no more plaque.    
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Incidentally the experiment that led to us first postulating that heat disease was caused by dietary cholesterol was an experiment that was done on rabbits in the early 1900s, by a young Russian scientist named Anitschkow. The problem of course was that Rabbits do not eat cholesterol as part of their normal diets and so their bodies very quickly hyper responded to it. [8] Humans however are very well adapted to eating cholesterol so the comparison was null and void but this did not stop decades of misunderstanding.
More resent research has shown that there is no link between dietary cholesterol and heart disease in all but the exceptional few but for many this news has yet to pierce the public conciseness which still holds to the old view. [9] [10]
Some experiments have even been done on the consumption of eggs, which have a very high dietary cholesterol levels and even these have shown no link with heart disease. [11] [12] [13]
Another irony of the “cholesterol is bad for your health” message is that the foods that tend to be high in cholesterol also tend to be very good for us and may in fact be preventative of heart disease and not a cause of it at all.

Better ways to lower Heart Disease 

avocado-sliced-in-halfIf you have high cholesterol, you can often lower it by far better means than cutting cholesterol from your diet. Simple lifestyle changes are often all that is needed.

For example, losing extra weight may help reverse high cholesterol.

Several studies show that simply lowering your body weight by as little as 5–10% can lower cholesterol and decrease the risk of heart disease in overweight people. [14] [15]

There are also many foods that can help lower cholesterol. These include avocados, legumes, nuts, fruits and vegetables [16].

Adding these foods to your diet can help lower cholesterol and reduce the risk of heart disease.

Being physically active is also important. Studies have shown that exercise has positive effects on cholesterol levels and heart health, particularly training with weights… but any and all exercise can help. [17] [18].

In conclusion

High blood cholesterol levels can be a risk factor for heart disease.
However, dietary cholesterol has little to no effect on blood cholesterol in most people and in fact could o-WEIGHT-LIFTING-facebook_copycause you to eliminate foods from your diet that may well help lower you risks of heart disease.

More importantly, there is no know significant link between the cholesterol you eat and your risk of heart disease.


Coach Aaron