Understanding Cholesterol - Part 1
When cholesterol is mentioned in conversation, most of us think of something bad like stroke or heart attack. However, cholesterol is necessary for maintaining health. All of our organ systems are composed of microscopic building blocks called cells. These cells are highly specialized for specific organs: heart cells, brain cells, kidney cells, etc.
Normal organ function is dependent on healthy cells and cholesterol is a critical substance for cell health, particularly in maintaining normal cell walls that keep each cell intact. Also, cholesterol is used to make (synthesize) adrenal hormones (cortisol), sex hormones (estrogen, testosterone) and vitamin D.
The liver needs cholesterol to make bile salts which are stored in the gallbladder and secreted into the intestine to facilitate fat digestion. Now, hold on! Before you go out and proceed to consume high cholesterol foods such as a marbleized ribeye steak, you need to know that our body, mainly the liver, is able to synthesize all of the cholesterol that we need. Ingesting high cholesterol foods is not necessary and in fact can lead to abnormally high cholesterol which can be detrimental.
Cholesterol is a lipid (fat) compound and therefore will not dissolve in blood (like oil in water). In order to transport cholesterol in blood throughout the body, the liver packages cholesterol into lipoproteins. Lipids that are attached to proteins can be suspended in blood and readily transported to cells. You are probably familiar with two of these lipoproteins known as LDL (low density lipoprotein) and HDL (high density lipoprotein). When your physician checks your cholesterol, typically total cholesterol, LDL, and HDL are measured. There are other lipoproteins present, so adding the values for LDL and HDL is less than the total cholesterol value.
LDL has been called the “bad cholesterol” and HDL the “good cholesterol”. When LDL levels are high, the LDL particles can become oxidized (think of metal oxidizing to form rust) and oxidized LDL particles can penetrate and damage arterial walls. This trauma results in inflammation of the artery (traumatized skin causes inflammation and crust/scab formation) and red blood cells and platelets (clotting cells) stick to the inflamed area thus the beginning of plaque formation (atherosclerosis). As plaques thicken, blood flow is compromised depriving organs of vital oxygen and other nutrients leading to disease states such as stroke and heart attack. As a side note, routine doses of aspirin are frequently recommended because it decreases the tendency of the clotting cells to stick to arterial walls inhibiting the early stages of plaque formation as well as plaque progression. If someone is suspected of having an acute heart attack, administering 4-6 325mg aspirin immediately to that person can be life- saving.
So, what are healthy or unhealthy cholesterol levels?
Goals for cholesterol levels should be customized to each individual based on that person’s risk factors for atherosclerosis. Risk factors include age, sex, genetics (family history), obesity, sedentary life style, tobacco use, low HDL and the presence of co-morbidities such as diabetes and hypertension. A person with multiple risk factors needs to pursue a much lower LDL level than what is recommended for the general population. General guidelines are as follows: LDL greater than 190 is very high; 160 to 189 is moderately high; 130 to 159 is borderline high; 100 to 129 is near optimal; less than 100 is optimal. For HDL, low is less than 40; borderline low is 40-50; optimal is greater than 60. Remember that HDL inhibits plaque formation so the higher the number the better. In fact, a low level of HDL is considered a risk factor.
The highest HDL that I have personally seen is 160! This was noted in a very healthy 90 y/o lady and likely due to outstanding genes although, she was very active physically and a red wine enthusiast. On the contrary, I followed a young male patient who had a lipid profile at age 30 that revealed a LDL of 240 and a HDL of 28. Despite aggressive lipid management, he required quadruple coronary artery bypass grafting (4 of 6 coronary arteries obstructed) at age 40!
So, what can be done if you have abnormal cholesterol levels?
There are life-style factors that can significantly impact LDL and HDL levels either positively or negatively and affect a person’s tendency to arterial oxidation and inflammation. Also, excellent prescription medications are available to help in achieving desired goals.
Grab a Herald Journal next week and we will discuss these factors in part 2 of Understanding Cholesterol.
Dr. Tippett is the founder of Comprehensive Quality Healthcare Providers a Concierge Internal Medicine practice located at 1210 Commerce Dr. Greensboro, Ga. 30642. He can be reached at 706-836-8182. Visit his website at www.drtippett.com.