What is Cholesterol and Why Does it Cause Heart Disease?

The story of cholesterol begins with understanding what cholesterol is, why it is important for us and why it can also be harmful.

Cholesterol is a complex molecule that is both absorbed into the body by our gut from the food we eat, and manufactured in the liver and brain from basic building blocks.  It is essential for life and found in all cells of the body – and a basic building block for parts of cell membranes, production of hormones and other important molecules in the body.

The problem with cholesterol is when it is present in abundance in cholesterol carrying particles called LDL.  The LDL particles have an outer shell or membrane with the inside containing cholesterol and other molecules including triglycerides, as well as a protein attached to the outside (apolipoprotein B) to tag it as an LDL particle, similar to a bar code or name tag.  These LDL particles shuttle cholesterol through the blood stream from the liver to parts of the body that need cholesterol for healthy function.  When these LDL particles find their way into the lining of blood vessels, plaque may form, which leads to heart disease and other forms of cardiovascular disease.

 Why do LDL cholesterol particles form plaque in some people but not others?

Cholesterol carrying LDL particles find their way into the lining of blood vessels and start the formation of plaque for a variety of reasons.  To begin with, think of the lining of blood vessels as a tight knit patch work sealing the contents of blood from leaving the blood vessel.  Certain factors making that lining more permeable less “watertight,” allowing the LDL cholesterol particles to slip into the layers of the blood vessel.  When those LDL particles are in the lining of the blood vessel, they are susceptible to a process called oxidation which chemically alters them.  Oxidation is a chemical process that is more likely when inflammation is present in the body.  When the house keeping cells of the body called macrophages find these LDL particles, they “eat” the LDL particles and form foam cells which is the early stages of plaque and atherosclerotic cardiovascular disease (ASCVD).

What can we do to reduce the risk of heart attack and cardiovascular disease?

By reducing the factors that lead to plaque, we can reduce the chance of plaque formation and heart attack.  There are two main ways to achieve this, reduce the amount of LDL particles or make the lining of our blood vessels healthier or “watertight” so that the LDL particles cannot escape to the outer lining to start the plaque formation process.

How to reduce cholesterol LDL particles?

There are a number of ways to lower the LDL particle number in our blood, both through diet and medication. Generally, a sugar free, low processed carbohydrate diet such as Mediterranean diet or DASH diet are recommended to help with cholesterol. High fiber diets may reduce the absorption of cholesterol. A variety of medications are available to reduce cholesterol, including statins, ezetimibe (which reduces absorption or cholesterol from the gut), PCSK9 inhibitors that allow the liver to eliminate more LDL particles from the blood in addition to a number of other agents.

How can I make the lining of my blood vessels healthier to lower my heart disease risk?

We look at “risk factors” for heart disease and by addressing them we can improve the health of our blood vessels.  Controlling blood pressure, treating diabetes through diet and weight loss as well as medication, avoiding tobacco products, lowering cholesterol LDL particles in the blood, regular dental cleanings and reducing the amount of inflammation in the body.