The Perpetuation of the Cholesterol Myth
Again this last week I have been spurred into action, taking-to-task two health experts on popular social media accounts.
I seem to be unable to let inaccuracies go un-challenged, especially when they come from qualified health experts and those whose credibility the general public accepts without question.
It feels like a never-ending job explaining to people the simple facts, even when they understand some of the complicated mechanisms for heart disease.
The second of my "beefs" relates to an Instagram influencer @heart.health.nutritionist.
Whilst quite a lot of her content relating to foods with adequate nutrients is quite good, she has fallen into the trap of accepting a few heart-health paradigms which lead her to inaccurate advice.
A recent post that she made highlighted the key factors in endothelial damage (endothelium is the inner wall lining of your arteries) being triglycerides, stress, hypertension and LDL.
There was a study in which mice were force fed cholesterol (in very large quantities) to justify the statement.
I would agree with all except the last one....LDL cholesterol.
Not only have I never read anything to suggest LDL damages artery walls, it would be the most monumental design flaw in the human body if it did, as our blood carries cholesterol around it continually for cell repair, amongst a host of other jobs.
Unlike most people, I follow links to these studies and read them.....and there were no clear conclusions that LDL caused damage to the endothelium. There were lots of mechanisms showing how damaged LDL particles when oxidised can create inflammation, but the study on some mice didn't reach the same conclusion she drew from it.
I felt compelled to share a study which, in humans, demonstrated the opposite, so I replied:
This is an interesting study, although seems not to show LDL actually damaging the endothelium, and doesn’t share any possible mechanisms for how this would happen…it seems to instead be concerned with the effect of LDL within the endothelium and the process of oxidation of LDL particles.
If it did indeed show LDL as a damaging particle, it would be at odds with large scale trials and research, which don’t support LDL quantity as a factor in heart disease risk or mortality.
For example, a major randomised controlled trial was done, between 1968 and 1973.
It was called the Minnesota Coronary Experiment (MCE). It had over 9,000 participants.
As found in earlier studies, replacing saturated fats with polyunsaturated fats reduced cholesterol levels somewhat.
However, and this is key, it had precisely no impact on cardiovascular disease.
More disturbingly, the greater the fall in the cholesterol level, the more people died.
For each 1% fall in cholesterol there was a 1% increase in the risk of death.
“There was a 22% higher risk of death for each 30 mg/dL (0.78 mmol/L) reduction in serum cholesterol.” As the authors of this study commented.
“Available evidence from randomised controlled trials shows that replacement of saturated fat in the diet with linoleic acid [a polyunsaturated fat] effectively lowers serum cholesterol but does NOT support the hypothesis that this translates to a lower risk of death from coronary heart disease or all causes.”
This study was published in the New England Journal of Medicine.
Michelle replied that she was too busy to read the study, despite the fact that it might fundamentally change her advice.
What is troubling, is that this type of "information sharing" re-enforces a recommendation to avoid saturated fat consumption erroneously.
Michelle, the owner of the Instagram account, also accepts the belief that salt creates hypertension. This is another myth, busted long ago scientifically, but taught to nutritionists through an out-dated curriculum.
We need to break the cycle of teaching very outdated and incorrect health advice in the curriculum of our nutritionists and health practitioners if we are ever to break free from advice that takes us in the wrong direction for our health.
The graphic above should be simple enough to understand for most people that get confused about the impact of cholesterol and saturated fat on their health.