According to the CDC, cholesterol is a “waxy, fat-like substance made by your liver.” Your body needs cholesterol to create hormones and digest fat. Your body makes all the cholesterol it needs, so it makes sense that most doctors would advocate eating as little as possible.
There are two types of lipoproteins that carry cholesterol throughout the body: High Density Lipoprotein (HDL) and Low Density Lipoprotein (LDL). HDL is the “good” cholesterol because it helps carry excess cholesterol to the liver where it’s removed from the bloodstream. LDL, on the other hand, is the “bad” cholesterol. It causes the buildup of plaque in the arteries, which leads to cardiovascular disease.
So the recommendation is simple: eat some HDL, and avoid LDL. End of story, right?
Does Cholesterol Cause Heart Disease?
Not quite. It turns out that there are different kinds of LDL particles. They can be “large and fluffy” or “small and dense” The large and fluffy particles are mostly benign, while the small and dense ones are the ones that cause plaque to build up in the bloodstream.
There are genetic factors that can determine whether or not you have larger or smaller LDL particles floating around in your bloodstream, but there are also lifestyle factors that come into play. The small and dense LDL particles are driven up by consuming processed sugars and starches, which contain little to no cholesterol. So what’s really going on here?
Incidentally, these foods are the same ones that lead to insulin resistance. Insulin resistance is known to cause weight gain in the form of fat, especially in the midsection. This excess fat, in addition to making you a bit shy during beach season, also causes whole-body inflammation and oxidative stress. Inflammation, in turn, is one of the biggest risk factors for cardiovascular disease.
Most people who have high cholesterol also have some level of insulin resistance and inflammation, so it’s hard to say which is the bigger factor when it comes to assessing cardiovascular risk.
This also brings up an important question: if LDL causes atherosclerosis (plaque buildup in arteries), shouldn’t it also occur in the veins? LDL is still present in the veins. One explanation is that the heightened oxidative stress brought on by excess body fat causes rancidification of cholesterol in the already oxygen-rich arteries, leading to plaque buildup.
The Role of Cholesterol in Cancer Prevention
To further complicate things, it seems that total cholesterol lowers the risk of cancer. 4 controlled, randomized studies analyzed by QJM Journal of International Medicine showed that statins (the drugs used to lower cholesterol levels), increased the risk of cancer. This is most likely because of the role cholesterol plays in immune system defense.
To say that high cholesterol is a causal factor in cardiovascular disease seems like a gross oversimplification. There are clearly other variables at play which warrant further research.
U. Ravnskov, K.S. McCully, P.J. Rosch, The statin-low cholesterol-cancer conundrum, QJM: An International Journal of Medicine, Volume 105, Issue 4, April 2012, Pages 383–388, https://doi.org/10.1093/qjmed/hcr243
Hyman M.D., Mark. “Cholesterol Is Not The Cause Of Heart Disease with Dr. Elizabeth Boham”. The Doctor’s Farmacy With Mark Hyman, M.D., Dr. Elizabeth Boham. https://open.spotify.com/episode/136fB7fz6AsKx2uK4lxH2c?si=19wba5zpToqjUtdZcGovKA