Sunday, June 6, 2021

Cholesterol - the good and the bad

    The next of the 3 "highs" that my cousin Charmain and I will be discussing is high cholesterol. High cholesterol is probably the most common among the 3 "highs".  The recommendation for treatment and diet is still evolving and changing as we learn more about it. The information that we are writing now in 2021, may be different from 2011 and probably will change again by 2031! 

    One of the most common blood tests patients request is for cholesterol. Physicians will usually order the lipid panel which includes the total cholesterol, triglycerides, high density lipoproteins (HDL), very low density lipoproteins (VLDL), and a calculated low density lipoprotein (LDL). I will go over what all these mean in this post and explain some of the misconceptions about cholesterol. 

What is Cholesterol?

    Cholesterol is the type of fat circulating in our blood. Every cell needs cholesterol, and it is the building block of hormone synthesis. One of the most important organs in our bodies, the brain, is largely made up of cholesterol. However, we all know that too much cholesterol can be harmful to our health. Most people probably imagine these fat to stick onto the inside wall of the blood vessel like a mound. In fact, these waxy fats start to accumulate within the blood vessel wall in a crystalized form, gradually narrowing the lumen where blood flows. This accumulation is called plaque or atherosclerotic plaque. There is a layer of the inside wall of the blood vessel, called epithelium, over the plaque. As the plaque grows larger, the epithelium is stretched and thinned. When it tears, exposing the cholesterol crystals underneath (called ruptured plaque), the body will attempt to immediately wall it off with platelets and fibrin like a wound, thereby blocking the entire lumen of the blood vessel. This sudden blockage of blood flow in a coronary artery will cause a heart attack; in one of the arteries supplying blood to the brain, it will lead to a stroke. 

    Triglycerides is another type of cholesterol and is the most common type of fat in our body. They are the fats from the food we eat—the storage form that any excess calories are converted to, and released when we need the energy. High levels of triglycerides contribute to fatty deposits on the blood vessel walls, increasing risk of heart attack and stroke. Very high level of triglycerides in the blood can "clog" arteries, causing pancreatitis. Imagine pouring oil down the drain! 

 LDL and HDL, low and high, which do you want high or low?

   Cholesterol is carried in the blood by a protein called lipoprotein. 

    LDL - low density lipoprotein, the "bad" cholesterol that deposits within the wall of the arteries causing atherosclerosis. 

    HDL- high density lipoprotein, the "good" cholesterol that picks up the excess cholesterol and transports it to the liver.  

    VLDL- very low density lipoprotein, transports triglycerides. So, its level goes up and down with triglycerides. 

    Too much LDL or too little HDL increases the risk for cardiovascular diseases (CVD) such as heart attack or stroke. There are subtypes of LDL, some larger and less dense, some smaller and denser and thought to be more atherogenic. There are a few laboratories that perform tests to further classify them, but in general the more LDL, the higher the risks for CVD. So, to summarize this, you want the bad LDL to be low and the good HDL to be high to reduce your risk for CVD.

What is high cholesterol? Hypercholesterolemia or Hyperlipidemia? or others?

    Hypercholesterolemia or hyperlipidemia is the term usually used for high cholesterol level in the blood. Since cholesterol is further broken down into LDL and triglycerides, there are other more specific terms. There are also classification based on lipoprotein dysfunction and genetics. Here, we will just use hypercholesterolemia. 

When do we start treatment for high cholesterol?

    Primary treatment for hypercholesterolemia is to prevent heart attack or stroke, so the level of cholesterol to start treatment is different for everyone. It depends on family history, other diseases and cardiovascular risk factors the person may have. The guidelines for treatment also changes frequently. As of 2021, normal person without any other risk factor, will consider medication for LDL higher than 160. Statins are the medications widely used for the treatment of high LDL. They are relatively safe and usually very effective in bringing down the LDL levels. There are also magnitudes of data showing that statins can significantly lower the risks of heart attack and stroke. 

What about fish oil or omega 3?

    Omega 3 has been used for the treatment of hypertriglyceridemia, high triglycerides in the blood. The 2 most studied omega 3 fatty acids are EPA and DHA. EPA has been shown recently to be beneficial in reducing the risks of CVD. While DHA is important in fetal development and thought to reduce the risk of Alzheimer's disease, recent studies have shown DHA to increase total cholesterol. So now the treatment of choice for hypertriglyceridemia is pure EPA omega 3 fatty acids. 

What can we do?

    Now that I have confused everyone with all the alphabet soup, let me confuse you more with what we can eat! We used to say eating fatty foods is bad, to avoid oil, red meat, eggs, shellfish and so on. Although we haven't really completely turned a 180, it is now OK to eat eggs, shellfish and butter! This part is where my cousin, Charmain dietitian can help and clarify. 

    Other things you can do:

  • Eat less sugar and carbohydrates
  • Exercise regularly
  • Lose some weight
  • Stop smoking
  • Drink less alcohol
    I hope this article helps you understand more about cholesterol. Feel free to ask us questions and we would love to hear comments and suggestions. Until the next blog on high sugar then!

1 comment:

  1. Very informative article, and easy to understand.
    Thank you very much. Looking forward to more good reads.