In my video Arterial Acne, I described atherosclerotic plaques as inflamed pockets of pus. Our coronary arteries start out healthy, but then the saturated fat, trans fat, and cholesterol in the standard American diet increases the cholesterol in our blood, which accumulates in the artery wall. This triggers an inflammatory response. This so-called fatty streak can then grow into an atherosclerotic plaque, which has the potential to rupture into our artery. If that happens, a blood clot forms, shutting off blood flow to a part of our heart, which can then die off and ultimately kill us.
What causes that final step, the rupture of the plaque? Ten years ago, researchers at Michigan State proposed a mechanism. They noted that when you look at ruptured plaques from autopsies of people who died from heart attacks, they were filled with cholesterol crystals protruding out from the plaque. So, the researchers wondered if maybe all that cholesterol in the plaque gets so supersaturated that it reaches a point where it crystallizes like sugar water forming rock candy. The growing crystals may then burst the plaque open.
To test out this theory they first made a supersaturated solution of cholesterol in a test tube to see if it expanded when it crystallized, and indeed it did-just like how water expands when it crystallizes into ice. In my video Cholesterol Crystals May Tear Through Our Artery Lining, you can see a massive cholesterol crystal shooting out the top of a test tube. Under a microscope, the tips of the cholesterol crystals were sharp jagged needles.
The researchers tried placing a thin membrane over the top of the test tube to see if the cholesterol needles would poke through, and indeed the sharp tips of the cholesterol crystals cut through the membrane. This suggested that the crystallization of supersaturated cholesterol in atherosclerotic plaques could indeed induce the rupture that kills us.
A test tube is one thing, but can you actually see crystals poking out in autopsy specimens? Yes, cholesterol crystals piercing the arterial plaque were found in patients who died with heart attacks, with extensive protrusions of cholesterol crystals into the middle of the artery.
What makes us think it was the crystals that actually burst the plaque? All those studied who died of acute heart attacks had perforating cholesterol crystals sticking out of their plaques, but no crystals were found perforating the arteries of people who had severe atherosclerosis, but died first of other, non-cardiac causes.
This can explain why dramatically lowering cholesterol levels with diet (and drugs, if necessary) can reduce the risk of fatal heart attack, by pulling cholesterol out of the artery wall, and decreasing the risk of crystallizing these cholesterol needles that may pop your plaque.
Given the powerful visuals, my Cholesterol Crystals May Tear Through Our Artery Lining video might be a good one to share with those in your life with heart disease, in hopes that they might reconsider eating artery-clogging diets.
Blocking the First Step of Heart Disease involves keeping our LDL cholesterol low by decreasing our intake of Trans Fat, Saturated Fat, and Cholesterol: Tolerable Upper Intake of Zero. Swapping red meat for white won't do it: Switching From Beef to Chicken and Fish May Not Lower Cholesterol
Does it matter if LDL cholesterol in our blood is small and dense or large and fluffy? See my video Does Cholesterol Size Matter?
Michael Greger, M.D.
PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:
- 2012: Uprooting the Leading Causes of Death
- 2013: More Than an Apple a Day
- 2014: From Table to Able: Combating Disabling Diseases with Food
- 2015: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet
- 2016: How Not To Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers
Image Credit: Sally Plank / Flickr. This image has been modified.