Cholesterol is Bad. Isn’t it ?
Cholesterol is Bad. Isn’t it?
If this is your first visit to the Blog, please go to Introduction or Index of All Posts.
In this post, we will talk about the controversial subject of “Cholesterol“. Almost 90% of the friends and family I speak to, think that Cholesterol is “Bad”. There are a few who think that there is such a thing as a “Good” Cholesterol along with a “Bad” Cholesterol in the body.
Aspects related to Cholesterol can be quite technical but keeping in mind the audience and philosophy of this Blog, I will try to keep it as non-technical as possible but to drive the message home there will be an element of technicality. Also there will be tables and pictures and the format will be a Q & A format. Entire books have been written on this subject and trying to do justice in a 3-4 page post is a significant ask.
Separately, not everything related to Cholesterol has been figured out despite what people have been led to believe. People are still doing significant amount of research and putting together all the pieces of the jigsaw. Hence, any statements made around this topic need to be taken with a pinch of salt.
I have used the following guidelines where I am quoting numbers and showing pictures
- I have not used data from people based outside the medical community or public health authorities (like WHO etc.)
- I have tried to use data and research undertaken by people within the medical community (doctors, researchers, professors etc.) but with a slightly contrarian and challenging views
There has been a publicity in the media and and also via public health literature (which is the reason why most people think Cholesterol is “Bad”) around Cholesterol. Almost universally the advice is that higher Cholesterol levels are bad. Some of them do recognise that there are Good and Bad Cholesterols.
So, as far as Cholesterol is concerned there are two camps:
- Cholesterol Proponents (I’ll call them CPs): This group thinks that higher Cholesterol levels are bad and cause heart disease or stroke. Most of this group also thinks that higher Cholesterol levels are caused by consumption of saturated fat. Again, 98%-99% of the establishment belong to this group (doctors, medical researchers, drugs companies, media, public health officials)
- Cholesterol Sceptics (I’ll call the CSs): This group thinks that a) higher Cholesterol levels do not necessarily cause heart disease and also that consumption of saturated fats to not cause heart disease. They think that something that is causing Heart Disease is also perhaps causing the Cholesterol levels to up (but not all the time and in all the people). In their words there is perhaps an association to some extent in some people between high Cholesterol and Heart Disease. To this group, high Cholesterol levels in normal population are a “Bio-marker” – a sign that something is wrong perhaps in the body and that Cholesterol does not itself cause Heart Disease. Whatever is making Cholesterol levels High is also causing the other problems in the body. Less than 1%-2% belong to this camp.
Across the entire post, the following abbreviations have been used:
- TC – Total Cholesterol
- HDL – High Density Lipoprotein
- LDL – Low Density Lipoprotein
- VLDL – Very Low Density Lipoprotein
- IDL – Intermediate Density Lipoprotein
- TG – Tri-glyceride
But both CPs and CSs agree on a few things mentioned below (and disagree on a lot more):
1. Cholesterol is absolutely essential to the body
Without Cholesterol we cannot survive. Cholesterol has a number of important functions in the human body
- Cell membranes – all cells in our body need Cholesterol to build their membranes
- Brain synapses – made predominantly out of Cholesterol
- Synthesis of Vitamins like Vitamin D
- Bile – Cholesterol is a key component of Bile etc.
As a slight anecdote, I would like to also mention a couple of things:
a) Mother’s milk is very rich in Cholesterol
b) A hen’s egg contains a good amount of Cholesterol
The one thing I can reasonably confidently say is that mothers never do or produce anything that harms their offspring intentionally. The reason why there is good amount of Cholesterol in an egg and mother’s milk is because it is very useful and essential for the babies.
2. You cannot have a Cholesterol level in your Blood
Again, this is indisputable. Cholesterol cannot dissolve in water and hence it cannot dissolve in blood. So it needs to be carried by something else (like a cargo in a ship or a sub-marine). The ships are called “Lipoproteins” (some of you may recall – HDL and LDL in your Lipid Profile blood test results – HDL stands for High Density Lipoprotein and LDL stands for Low Density Lipoprotein.). Blood tests measure or estimate the cargo – the actual cholesterol but technically you cannot have a Cholesterol in the blood directly.
3. Cholesterol you eat (Dietary Cholesterol) has no bearing on your Blood Cholesterol levels
Cholesterol is so essential to our survival that Liver and most cells can manufacture Cholesterol from raw ingredients. Approximately 75% of the Cholesterol is produced within the body with around 25% coming from food sources. Just to give you some perspective, the entire amount of Cholesterol in our body is approx 30-40 gms and the daily need is around 800-1200 mg (milli-grams). If you eat 600 mg, your body will produce 600 mg and if you eat 1200 mg body will produce none. So the human body will produce whatever Cholesterol is necessary whether you eat it or not. Compare this to the amount of fat (Tri-glycerides) in a typical person (weighing 75 kgs and approx 20% body fat) – 15,000 gms (15 kilos)
What is Cholesterol anyway?
Cholesterol is an organic molecule which is a steroid alcohol (but does not behave like a normal alcohol). It belongs to the Lipid class (like other fats). It does not dissolve in water entirely.
That’s enough I think.
How many types of Cholesterol are there?
As discussed earlier, Cholesterol is carried by protein molecules called Lipoprotein. Lipoproteins also carry fat (Tri-glycerides – TG), Phospholipids etc. We will concern mainly with Cholesterol and TG.
There are only two types of Cholesterol – Free or Unesterified Cholesterol (UC) and Esterified Cholesterol (called CE). (there are other categorisations around Cholesterol in animals and Cholesterol in plants but we needn’t concern ourselves with that).
But why I do hear about LDL, HDL, VLDL etc.?
These are different types of Lipoproteins that carry the Cholesterol. Last time I read, there are five major types and many sub-types of Lipoproteins. Altogether I counted 16 different types of Lipoproteins as per the picture below (courtesy Dr.Peter Attia). It is highly confusing to say the least and apparently even a lot of doctors don’t know about this..
The main types of Cholesterol are Chylomicron, VLDL (Very Low Density Lipoprotein), IDL (Intermediate Density Lp), LDL (Low Density Lipoprotein) and HDL (High Density Lipoprotein) in ascending order of density. There is something called Lp(a) which is a type of LDL but again we needn’t worry.
The following picture shows the density and typical cargo for a given Lipoprotein type (or class).
A couple of Observations: LDL has more Cholesterol in general compared to HDL and VLDL and Chylomicron has the highest amount of Fat (Tri-glyceride). In general, as the density keeps increasing, there is less Fat carried by the Lipoprotein and more protein carried by the Lipoprotein (from wiki)
How does a Lipoprotein look like?
The below picture shows a typical Lipoprotein in case you are interested.
How is Cholesterol measured or How do I read my Lipid Profile or Cholesterol test results?
As mentioned earlier, Cholesterol is measured by breaking open the Lipoproteins and measuring the underlying Cholesterol. Despite the number of tests performed and the amount of medication prescribed based on the tests, the most used Lipid Profile test uses a degree of estimation and approximation in identifying Cholesterol levels associated with various Lipoproteins. Not all Cholesterol is measured. Only some components are measured.
TC = HDL + LDL + IDL + VLDL + Chylomicron + a couple of other Cholesterol types
Assumption 1: IDL and Chylomicron are negligible. So they are set to 0.
TC = HDL + LDL + VLDL
Assumption 2: Cholesterol in VLDL is approximately 20% (or 1/5th) of Total Triglycerides (TG)
TC = HDL + LDL + (TG/5)
In the test TC and TG are measured and based on the results LDL is calculated.
LDL = TC – HDL – (TG/5)
That’s how your Cholesterol levels are calculated.
TC = 220 HDL = 50 and TG = 180
LDL = 220 – 50 – 36 (180/5)
LDL = 134
Actually, Cholesterol is measured in 2 different units – milli-mole / litre (mmol/l) in UK / Europe etc. and milligram / deci-litre (mg/dl) in US, India etc. The above equation is for calculations based on mg/dl.
The equivalent calculation for mmol/l is TC = HDL + LDL + (TG/2.17)
The normal Lipid test is simple, practical and relatively in-expensive. The only thing needed is a 12-hr fast and works well in most cases.
But it has been proven to be incorrect in individuals who are highly “Insulin Resistant” and have extremely high or extremely low TGs.
Pls go to Part 2