Thursday, April 4, 2013

Head Scratcher

It's a head scratcher that an organization like this - the health newsletter of Harvard - is lazily recommending actions that are ten years out of date.  Even the institution's own scientists have moved past the "lowfat to lower cholesterol" fad and back towards science.
The emailed newsletter starts:
"People can reduce cholesterol levels simply by changing what they eat. For example, if you are a fan of cheeseburgers, eating less meat (and leaner cuts) and more vegetables, fruits, and whole grains can lower your total cholesterol by 25% or more. Cutting back on saturated fat (found in meat and dairy products) and trans fat (partially hydrogenated oils) can reduce cholesterol by 5% to 10%."

They recommend these four things to "lower your cholesterol":
"Stick with unsaturated fats and avoid saturated and trans fats.  
"Get more soluble fiber. 
"Include plant sterols and stanols in your diet."

Head scratcher part 1: There's no evidence - after forty years or more of examination - to show that "lower cholesterol" is a benefit for mortality reduction.  Your government, in its infinite wisdom, spent nearly a billion dollars to prove that its advice to reduce cholesterol and fat intake was in fact good for mortality reduction.  Said government failed to show any such thing.  

Second, eating plant sterols and stanols to lower cholesterol is equivalent scratching your private parts to make the sun come up sooner - I guess is might work, but the evidence is sketchy.  Sure, if you believe the conjecture that cholesterol is a cause of early mortality by causing damage to blood vessels, then it might be considered a common sense thing to use a "natural" plant based "food" to lower cholesterol.  But after forty years, and still no direct evidence that cholesterol manipulation via diet (or statin) is helpful for reduced all cause mortality - REALLY?!  A dearly beloved family member would dutifully down benecol every night on a piece of bread and announce proudly that it was "reducing" her cholesterol - how I managed to keep my pie hole shut about that I'll never know.  The kicker?  For females her age, "low cholesterol" correlates with increased mortality.  
The idea that fiber helps mortality is all the rage, but suffers, like the idea of diet to reduce cholesterol, from a lack of evidence.  Why people remain so in love with the idea is a little confusing when there are so many reasons not to down magnum doses of fiber and so little in the way of evidence that fiber is a big benefit - or any benefit.
The topic of cholesterol and causation of disease is very, very complex.  Seems like folks with "high LDL" (which can mean a lot of cholesterol packaged in LDL particles, or a large number of LDL particles, or some combination of both) have a higher correlation with heart disease; but some folks with "normal" LDL die young (Tim Russert being a prime example, his was reportedly 70, which is "low").  HDL has a correlation with reduced mortality, but efforts to raise HDL do not decrease mortality.  Insurance companies - who have a lot more at stake in your health than do your doctors - bet on your ratio of total cholesterol to LDL cholesterol.  
I read this newsletter to gauge changes in the perception of the common view.  At least this perspective - of doing what is best for you based on changes you can verify for yourself without relying upon "expert opinion" - has become obvious for the old guard.  They advise:
"Find the diet that work for you. When a friend or relative tells you how much his or her cholesterol level dropped after trying a particular diet, you may be tempted to try it yourself. If you do and after a few months you discover that you’re not getting the same benefits, you may need to chalk it up to genetic and physiological differences. There is no one-size-fits-all diet for cholesterol control. You may need to try several approaches to find one that works for you.  Although diet can be a simple and powerful way to improve cholesterol levels, it plays a bigger role for some people than for others. If your doctor suggests a lower-fat, lower-cholesterol diet, and despite your best efforts it isn’t working, you may need a different kind of diet, or medication, or both to bring cholesterol down."
It is curious to consider how this will all play out over time.  I don't see a day when all of the "experts" who have advocated low fat and statins to save the world will just have a conference and announce "what we've been telling you was bogus."  At some point, however, the truth will be too obvious for any rational denial.  The "It's the Sugar, Stupid" paper (from Monday and Wednesday's post) will be another nail in the "low fat for health" coffin, making the causality chain something like:
1. Too much sugar causes metabolic derangement (metabolic syndrome)
2. Unchecked, metabolic syndrome progresses to diabetes (full blown loss of glycemic control), and excess carbohydrate in general exacerbates the issue once one is over the metabolic syndrome threshold
3.  Diabetes predicts about a ten year shorter lifespan, and a much shorter period of active life.
The role of fat and cholesterol in this chain is minimal, and if eating high fat and high cholesterol helps you retain glycemic control and avoid metabolic syndrome, we've been in reverso-world the last 30+ years.

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