Increasingly over the past few years I have been suggesting that people stop worrying about their cholesterol numbers since for the great majority of us, cholesterol level is irrelevant to the process of cardiovascular disease.
This has been made obvious by the results of many longitudinal studies where time and time again it has been observed that statins work their benefit independently of cholesterol response. I even advocate a return to natural butter, fresh eggs and whole milk in our diet.
But there is one form of cholesterol that is still very much our enemy and that is oxycholesterol, the oxidized form of cholesterol. Oxycholesterol is the result of exposure of natural, non-toxic cholesterol to the oxygen in the atmosphere. With such exposure, harmless natural cholesterol gradually becomes our bitter enemy.
You may recall Kilmer McCully's reflections on rabbit atherosclerosis in his book, "The Homocysteine Revolution." Research in the early ‘60s showed severe atherosclerosis resulting in rabbits fed cholesterol-laced rabbit food. To most minds that was irrefutable proof of the toxicity of cholesterol. You feed rabbits cholesterol; they get atherosclerosis - what more do you need to know.
But McCully introduced us to the two faces of cholesterol. Even though the researchers in the rabbit studies started with harmless, natural cholesterol it was soon converted to the toxic form when, as a component of their pellet food, it was exposed to air.
McCully documented this conversion process rather dramatically by showing that natural, fresh cholesterol could be injected directly into arterial walls with impunity but once it had converted to the toxic, oxycholesterol form, arterial injection resulted in severe atherosclerotic plaque development.
This process takes place daily in our foodstuffs. Powdered eggs contain some 60 times the oxycholesterol of fresh eggs.
The same goes for fresh milk versus dried milk powder. The same process goes on with any foods in which powdered eggs or milk are used as ingredients. Are there any cookies out there on our grocery shelves made with fresh milk or eggs? I doubt it because of economic considerations - fresh eggs and milk are much more costly. Even our left-overs can become relatively harmful after a few days when any natural cholesterol it might have contained has converted to the oxy form because of air exposure.
Think about these truths during your cooking and shopping and take care, for this is one form of cholesterol that is your enemy and will remain so.
Duane Graveline MD MPH
Former USAF Flight Surgeon
Former NASA Astronaut
Retired Family Doctor