Low-Density Lipoproteins, or LDL, as its name implies, are composed of Lipids/Fats (Lipo-) and Proteins. Cholesterol is a necessary nutrient, which is why the cells of our bodies make the majority of its own cholesterol, but we also obtain cholesterol from our diets. LDL particles carry cholesterol, fatty acids (triglycerides), phospholipids, and proteins, however, the majority of “cargo” on the LDL particle is cholesterol. LDL particles are necessary for transporting fats and cholesterol throughout the body as these compounds cannot travel in the bloodstream due to their hydrophobic nature (not liking water).
Hopefully, the very brief explanation of how LDL differentiates from actual cholesterol is helpful. Please note there is more to the topic of blood lipids than we will discuss today, but know I plan on discussing them in the future.
Today we will be looking at a few papers which highlight the important role LDL plays in our immune system. At this point, the majority of what you have probably heard about LDL is negative. There are a fair number of doctors that believe the lower one’s LDL levels the better, however, I would say it is not that simple. There is a concept known as the Diet-Heart Hypothesis, which:
“Predicts that the serum cholesterol lowering effects of replacing saturated fat with vegetable oil rich in linoleic acid will diminish deposition of cholesterol in the arterial wall, slow progression of atherosclerosis, reduce coronary heart disease events, and improve survival.” (Ramsden et al., 2016)
Unfortunately, we will not be diving into the validity of the Diet-Heart Hypothesis, rather, I want you to know where the rationale for lowering LDL levels originated. Given the Diet-Heart Hypothesis, one would think that the higher one’s LDL Cholesterol (LDL-C) the greater their risk of dying from any type of chronic disease (all-cause mortality), right?
Not necessarily.
A systematic review by Ravnskov et al. in 2016 did not find that to be true. Instead, there was either no association or an inverse association between LDL-C and both all-cause and cardiovascular mortality. Meaning, a higher LDL-C has either no impact on your risk of death or it may decrease your risk of death from all causes.
How could a higher LDL-C increase one’s lifespan? This is because LDL-C plays a role in our immune system, as high cholesterol may protect against infections and atherosclerosis. LDL also binds to and inactivates various microorganisms and their toxic products.
Are there studies that show high cholesterol, therefore higher LDL-C, is associated with longevity? Yes.
The Leiden 85-Plus Study looked at 724 Netherland participants aged 85 years and older and found:
“Mortality from cancer and infection was significantly lower among the participants in the highest total cholesterol category than in the other categories, which largely explained the lower all-cause mortality in this category.”
The authors also found a corresponding 15% decrease in mortality for every 38 mg/dL increase in total cholesterol.
Moreover, a study out of Iceland looked at 105 people aged 80 years and older. The average Total Cholesterol (TC) level of these individuals was around 220 mg/dL and those with the highest TC had less than half the all-cause mortality of those with lower levels.
As you can see, the topic of cholesterol, which includes LDL-C, is nuanced and slightly confusing, especially when you consider what you have been told this whole time.
I would be remiss if I did not clarify that dyslipidemia, so high triglycerides, LDL-C, TC, and low HDL along with elevated fasting insulin and blood glucose levels would not be signs of optimal metabolic health. Alternatively, in the context of normal fasting insulin, fasting blood glucose, low triglycerides, and high HDL, high total cholesterol and LDL-C may not be as harmful as we have been led to believe.
This information is highly controversial, and just so I clarify, this is not medical advice. Instead, my goal is to present information that I find interesting, however, at times, the information may challenge the current medical and nutrition recommendations put forth by our governing bodies. My hope is this information allows one to critically think and not blindly trust the information I, or other health professionals, spout. I want you to feel empowered to take control of your health.
I hope you found this information interesting. If you have questions or suggestions for topics you would like me to cover please do not hesitate to reach out!
That’s all for now!
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