Fluffy Particles, Solid Fats & Cholesterol Tests

How do you lower your LDL cholesterol 60 points in 4 weeks or less?

Get it tested twice.

Let me back up. Since August 2010, I’ve been on a “paleo-inspired” diet high in animal fats and low in grains and legumes (low as in “none”, see my post I Eat Staples for a full breakdown of my diet). I was first interested in the idea of utilizing evolutionary history to construct an optimal diet after reading the NYT article “The New Age Cavemen and the City” but I wasn’t convinced to give the diet a try until after watching the low-budget documentary Fat Head*, a mix between a response to Super Size Me and a debunking of the lipid hypothesis. Rapidly increasing my intake of red meat and saturated fat prompted many warnings about the consequences, namely that I would gain a lot of weight very rapidly. When the opposite occurred, warnings remained but they instead addressed the invisible and long-term risk of heart attacks. Given the stigma and fear surrounding saturated fat in this society, I probably gave someone a heart attack every time I drank heavy cream in public.

Science and Math Ahead!

There are several levels of the cholesterol test with the lowest, cheapest and most useless one simply providing you with a total level of your “cholesterol” (you’re not actually measuring cholesterol, but the lipoproteins that carry it…but whatever) with no distinction between HDL (high-density lipoprotein, also known as “good” cholesterol for its protective effects) and LDL (low-density lipoprotein, also known as “bad” cholesterol for its potential inflammatory and plaque contributing effects. More on this later…). The next step up is in all likelihood what you received the last time you had your cholesterol levels since it’s relatively informative given it’s price tag (roughly $25) but it has several drawbacks. The standard lipid panel test will measure HDL, total cholesterol and triglycerides directly, but will calculate the rest of the numbers using these formulas:

Total=HDL+VLDL+LDL; Triglycerides=VLDL*5

VLDL is calculated by dividing triglycerides by 5, although this becomes unreliable as triglyceride levels increase beyond 200 mg/dL and above. LDL levels are calculated based on what the remainder is but with no indication of what type of particle you are carrying. If you thought that “bad” versus “good” cholesterol was confusing enough, this would only make matters worse as you can subdivide LDLs even further based on their particle size. LDLs can either be large and fluffy (Pattern A) or small and dense (Pattern B). Relatively recent research has shown that it is LDL particles carrying polyunsaturated fatty acids (i.e. linoleic acid, the fat found in tremendous quantities in industrial seed oils, think soy and corn oil) that are susceptible to oxidation with small, dense LDL particles particularly susceptible to oxidative damage given their tendency to become trapped in a vessel wall. Long story short, a diet high in saturated fat has been shown to raise your LDL levels but of the large fluffy particle kind (the “good” LDL if you will). Furthermore, given the chemical structure of saturated fat, it is particularly resistant to oxidation while carried in an LDL particle. Those two factors, the near-impossible oxidation of saturated fat and the tendency for small LDL particles to get stuck in vessel walls, cannot be conveyed through the standard lipid panel given that LDL levels are not even directly measured, let alone subdivided into their respective categories. Hence, the only way to get an accurate picture of your LDL levels is through direct measurement via what is commonly known as a Verticle Auto Profile test. An example of what such a test would look like can be found courtesy of Gary Taubes, note the LDL pattern distribution found on the third page.

This last paragraph is by no means meant to be a definitive explanation but should give you enough of a footing to understand the results.

The Results

So I tried to get a VAP test in order to get an accurate and detailed look at my cholesterol levels, I was instead amazed at the difficulty of said prospect. Universally, doctors and nurses had no idea what I was talking about when I said VAP test. The first doctor I encountered acted almost personally offended that I would request such a test and simply directed me to the standard lipid panel. The second doctor was not a condescending asshole and was completely cooperative (Best line: “I’ve never heard of this test but maybe we can both learn something from this!”) until I found out that the VAP test costs something like $500 and is not covered by insurance. So I didn’t get a VAP test. Instead, you people will have to make do with two standard lipid panels taken within a month. Away!

Standard Lipid Panel “Ideal” Range 4/20/2011 5/27/2011
Cholesterol, Total 100-199 mg/dL 274 mg/dL 219 mg/dL
Triglycerides 0-149 mg/dL 65 mg/dL 65 mg/dL
HDL Cholesterol > 39 mg/dL 76 mg/dL 84 mg/dL
VLDL Cholesterol Calc 5-40 mg/dL 13 mg/dL 13 mg/dL
LDL Cholesterol Calc 0-99 mg/dL 185 mg/dL 122 mg/dL

I have high cholesterol…sort of and maybe? I knew from the beginning that I couldn’t trust the LDL levels from a standard lipid panel to give me an accurate picture of my situation. The first doctor gave me an earful about my “borderline high” LDL levels (“Try to reduce your saturated fat and trans fat intake”) but was congratulated on my very high HDL levels (“You must be really athletic!”, “Not really…”, “…oh”). Based on the guidelines available to her, I was informed that the recommendations would be to prescribe statins (cholesterol lowering drugs) had my LDL been over 190 instead of just 185. Again, I completely discounted the results because I knew how many shortcomings the standard lipid test had so I therefore made no changes to either my diet or my activity levels, and I certainly did not start taking statins. A month later, I found another clinic and took another blood test and the results completely floored me. My LDL levels went down 33% in the span of about a month with absolutely NO CHANGES to my lifestyle. Instead of discussing statins, my doctor congratulated me on the protective factors I had (very high HDL, very low triglycerides) and told me not to worry about my slightly elevated LDL levels.

Random variance in any biological marker is certainly to be expected, but what absolutely floored me is how dramatic the change was for me. This episode only gave me more contempt for the medical profession. The fact that so many decisions (statins & regimen) and so much tracking (statins/regimen is working/not working) is based on a test that can swing at least 33% is any given direction based on nothing is somewhat terrifying. Chris Masterjohn expanded on the “regression to the mean” phenomenon in an excellent article over at his blog called “How a Study Can Show Something to Be True When It’s Completely False — Regression to the Mean”:

Regression to the mean is, in short, the tendency for really high values to fall towards the average value upon a second measurement and the equivalent tendency for really low values to rise towards the average value in the same way.This is incredibly common in research studies and if researchers do not randomly allocate subjects to control and treatment groups, or if they do but that randomization does not effectively produce equivalent characteristics within the two groups, or if the authors do not report the raw baseline values so that we as readers can verify that the randomization was effective, the study will be plagued by the vagaries of regression to the mean and its results will be completely uninterpretable.
If we are to read research critically, we should examine every study purporting to show a change in some measurement for regression to the mean.No stone should ever be left unturned.

Even though I didn’t get the venerated VAP test, it’s still possible to extrapolate your LDL pattern distribution based on your triglyceride levels.

From Austin et al 1990. “Phenotype A” means that large LDL particles dominate; “phenotype B” means that small LDL particles dominate.

Given my ultra-low trygliceride levels of 65 mg/dL, that would put me squarely favoring Pattern A (The “good” kind) LDL particles at around 70% likelihood. We can’t know for sure given genetic factors and whatnot, but it’s a good start until I get an actual VAP test. Therefore, even my “worrisomely” high LDL levels is protective given what I mentioned earlier about the benefits (or perhaps the benign nature) of fluffy LDL particles.

However, the bigger question really is whether a healthy, lean, non-smoking, 26 year-old male with no family history of heart disease should even be worried about getting a heart attack to begin with, even without considering the protective factors. I’ll leave you to ponder that while I go grab some cheese.

Also, this video still makes me laugh:

*  Watch this hour long presentation titled “How Bad Science and Big Business Created the Obesity Epidemic” for a primer on why saturated fat is vilified. You can watch “Fat Head” either on Hulu or Netflix but the smarmy tone and sarcasm in the first half of the film is often very off-putting to people, which is a shame since the latter half is incredibly informative and clear. Skip to about 50 minutes in if you’re going to watch it.

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