LDL (low-density lipoprotein)-C or LDL cholesterol is commonly referred to as the “bad” cholesterol and HDL cholesterol is the good kind.
This good vs evil dichotomy of thinking is prevalent to this day in mainstream medical literature.
For example, according to Johns Hopkins Medicine, LDL cholesterol levels are a major factor in risk for cardiovascular disease. Hopkins recommends that people with cardiovascular disease should take medication if their LDL level is 70 mg/dl or higher.
LDL, which is actually a fatty protein, not technically a cholesterol, is the fall guy for heart disease. That’s because LDL tends to accumulate in arterial walls. Consequently, blood flow can stagnate. Stroke, heart attacks or heart disease can result. Numerous studies show that LDL-C is associated with a higher rate of cardiovascular disease?
In light of this, should you make it your mission to get your LDL level as close to zero as possible?
Well, maybe not.
On one hand, LDL-C, especially small dense particles, contribute to atherosclerosis, a hardening of the arteries. On the other hand, LDL-C carries out vital functions in the cardiovascular system.
What Does LDL Cholesterol Do?
LDL carries two types of cholesterol to cells that need it. Without LDL, cells wouldn’t be fortified with their protective cell membranes. Most of the cholesterol in your body is composed of LDL-C.
Without LDL-C, your skin would be unable to synthesize vitamin D from the sun. You would have no sexual function or strength, as LDL plays a critical role in the manufacturing of sex hormones. LDL also is critical for providing structural and functional support to brain matter.
In a nutshell, every single bodily tissue in the body requires cholesterol. And remember, most cholesterol is of the LDL variety.
Why High LDL is “Bad”
High LDL levels, in addition to being a major contributing factor to cardiovascular disease, can also cause dyslipidemia. Dyslipidemia refers to abnormally high levels of lipids (fats) in the blood, which in itself can lead to heart disorders.
Numerous research demonstrates that high levels of LDL-C and an inverse of low HDL-C contribute to the development and progression of atherosclerosis. When LDL-C levels are high, it indicates that there’s a substantial amount of cholesterol that has entered the arterial walls.
According to University of Texas Southwestern Medical Center, in the early stages of atherosclerosis, LDL that has entered the artery wall attracts and is engulfed by important immune system cells called macrophages that ingest, or "eat," LDL particles. Then, the macrophages that have feasted on LDL-C become a mass of foam-like cells, which triggers an inflammatory response, in which plaque builds up in the walls of the arteries.
As atherosclerosis progresses, plaque causes the arteries to narrow and become unstable. Plaque can break apart and cause blood clots which restricts blood flow to vital organs such as the brain and heart.
In 2019, researchers from UT Southwestern Medical Center discovered that if they deleted a certain protein (SR-B1) from the endothelial cells that line the blood vessels, far less LDL entered the artery wall. The study was conducted on mice; the results will hopefully carry over to people in large clinical trials one day.
Not All Researchers Think LDL-C Is A Major Factor For Heart Disease
Some researchers who are clearly in the minority believe LDL-C is not alone a solid indicator of cardiovascular disease. For example, ScienceDaily.com reports that a study conducted at Texas A&M University shows that exercise can actually raise LDL levels. The study examined 52 adults, ranging in age from 60 to 69. The subjects were all in generally good health, absent of chronic diseases like CVD. However, the adults were not physically active.
After performing moderate-intensity-to-fairly vigorous exercise, the participants who had gained the most muscle mass also had the highest levels of LDL (bad) cholesterol.
Even the researchers were shocked. "A very unexpected result and one that surprised us,” said lead researcher, Texas A&M’s Steve Riechman, per ScienceDirect.com. The takeaway from the study is that the more LDL you have in your blood, the more you’re able to build muscle during resistance training.
In another study published in Neurology, researchers took MRI brain scans of 2,608 adults. The MRIs revealed damage to small blood vessels and changes in the brain’s white matter, which are associated with small strokes. Counterintuitively, the study demonstrated that higher levels of LDL were associated with less risk of the brain changes that are associated with stroke.
Riechman said that many people often say that one of their health goals is to get rid of their bad LDL cholesterol. “But the fact is, if you did so, you would die." As a result, Riechman suggests, “We need to change this idea of LDL always being the evil thing -- we all need it, and we need it to do its job."
However, there can be no doubting that the overwhelming majority of research studies show an association between high LDL-C and arteriosclerosis.
Other Contributing Factors To Cardiovascular Disease
In addition to high LDL-C levels, there are several other root causes of heart disease including high triglycerides (caused by a high-carbohydrate diet), a sedentary lifestyle, stress and high-blood pressure, genetics (including apolipoprotein B deficiency), smoking, having diabetes, and environmental factors.
Cardiovascular disease is multifactorial. Even if you eat a relatively healthy diet, if you have chronic stress and don’t manage it very well, you can develop heart disease. Generally speaking, the lower your LDL-C level is, the better. To evaluate your risk of developing cardiovascular disease you can request a lipid panel from your doctor if you haven’t had your blood work analyzed in a long time. You can also request genetic tests to assess your heart disease risk.
Last but not least, adopting a Mediterranean Diet-like eating plan that’s low-sugar, low-starch, nutrient-dense, consisting of high-fiber veggies may be your best prescription for keeping LDL-C low—but not zero.