Cholesterol is not actual cause for heart disease, inflammation is. In a minute you will understand how. Before that we need to understand inflammation.
Definition of Inflammation is ‘a localized physical condition in which part of the body becomes reddened, swollen, hot, and often painful, especially as a reaction to injury or infection‘.
There are two types of inflammation:
- Acute and
When inflammation occurs and it hurts (visible and painful) it is acute. Examples include, rash on you skin, when you get your toe stubbed or a splinter in your finger.
Chronic inflammation goes unnoticed as it occurs within arteries. It is not only responsible for heart diseases but for Cancer, Arthritis, Diabetes, Obesity and loads of other diseases.
We are going to look into Chronic inflammation and how it causes heart attack.
But before that we need to deal with something else called oxidation.
What is Oxidation?
We know that electrons revolve around an atom in orbits. And electrons in the last orbits are known as valence electrons. These valence electrons can easily be lost. When an atom loses an electron it is called ‘Free Radical‘ and it needs an electron to fill the place of lost electron. Therefore, it tries to pair with another atom or molecule. And if it does pair, then the paired molecule has been oxidized.
note: rusting of metal is due to oxidation.
Okay, now we know what is inflammation and oxidation. Keep them aside. We need to discuss another concept to understand completely. And yes, this is the last concept.
Function of LDL and HDL:
Both, LDL and HDL are two types of Cholesterol. However, when you take cholesterol measurement, it is the measurement of LDL.
Function of LDL is to carry cholesterol from liver and supply to various organs and tissues.
Function of HDL is to take excess LDL back to liver.
Hence, it is necessary to have a higher ratio of HDL to LDL.
Okay, we are done with concepts. Now, we shall take a look into
How Heart Attack Occurs?
Free radical keep on looking for some molecule to pair with. And guess who it finds? LDL cholesterol, the one responsible for supplying cholesterol to various tissues and organs. LDL after pairing with Free Radical is no longer LDL but oxidized LDL.
Coronary arteries have a thin sheath between blood and the artery called as endothelium. Being very thin and delicate the oxidized LDL, while passing through coronary artery enters the endothelium starting inflammation.
When inflammation begins, immune system sends monocytes (biggest type of white blood cells). Monocytes release cytokines which are vital for immune system response. Consider Cytokines as a regulator for immune system.
Unfortunately, these cytokines are themselves inflammatory. They increase the inflammation process and cause the endothelium to secrete sticky molecules called ‘adhesion molecules’.
These adhesion molecules stick with monocytes and they together form Macrophages. Function of macrophages is to eat all the problem causing element. In this case it is the oxidized LDL.
However, there is one problem. There is no limit to how much a macrophage can eat. It will continue to eat until it bursts.
So, oxidized LDL keep on attacking endothelium, the macrophages will keep on eating oxidized LDL. When macrophages eat too much they burst and leave a yellow streak.
Body considers the yellow streak as foreign body and blood rushes to form a clot. This blood clot blocks the flow of blood. And there you have a Heart Attack.
In most cases, blood clot is minor and goes unnoticed. If inflammation process is stopped then inflamed area turns into a scar and heals itself. But if inflammation process continues, the cycle continues and layer of plaque (fatty streak forms into plaque over time) keeps on forming. Further decreasing area of blood flow.
And the reason cholesterol gets the bad rep is due to LDL’s ability to get oxidized and being at the spot of clot.
Here we come to our conclusion that cholesterol is not the main cause but inflammation.
Therefore, reducing inflammation must be our first step. And we shall learn how to decrease inflammation in our next post.