Marks Daily Apple
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21 Dec

How to Interpret Cholesterol Test Results

cholesterolBefore we get into the big job of interpreting cholesterol numbers, let’s review what cholesterol actually is.

Cholesterol is cholesterol: a waxy steroid of fat that serves as an essential structural component of cellular membranes and in the production of steroid hormones, vitamin D, and bile acids. Contrary to what the terminology indicates, there’s actually only one “type” of cholesterol in the human body, and it’s called, quite simply, cholesterol. What we think of when we use the word “cholesterol” is actually a lipoprotein – a fatty conglomerate of protein and lipids that delivers cholesterol and fat and fat-soluble nutrients to different parts of the body. It’s not just free cholesterol floating around in your blood; it’s cholesterol bound up by lipoproteins.

So LDL, HDL, VLDL, all those (in)famous measurements we get at the doctor’s office are just different types of lipoproteins. They’re not actually cholesterol. I discussed this briefly a couple years back, and there’s always Griff’s big primer in the forum, so take the time to go check out both. And also take a peak at The Definitive Guide to Cholesterol for review.

Okay, let’s talk about the most commonly bandied-about cholesterol numbers: LDL-C and HDL-C. What do they really mean? What are they actually measuring?

To understand what these numbers mean, let’s play the freeway analogy game. Both LDL-C and HDL-C, the standard, basic readings you get from the lab, do not reflect the number of LDL or HDL particles – the number of lipoproteins – in your serum. Instead, they reflect the total amount of cholesterol contained in your LDL and HDL particles. Hence, the “C” in LDL/HDL-C, which stands for “cholesterol.” Measuring the LDL/HDL-C  and then making potentially life-changing health decisions based on the number is like counting the number of people riding in vehicles on a freeway to determine the severity of traffic. It’s data, and it might give you a rough approximation of the situation, but it’s not as useful as actually counting the number of vehicles. A reading of 100 could mean you’re dealing with a hundred compact cars, each carrying a single driver, or it could mean you’ve got four buses carrying 25 passengers each. Or it could be a couple buses and the rest cars. You simply don’t know how bad (or good) traffic is until you get a direct measurement of LDL and HDL particle number.

Say you go ahead and get those particle numbers directly measured. You’re still limited, because that is just a single datapoint from a specific time in your life/day/week. Analogies are fun and helpful, I think, so let’s take this traffic and freeway stuff further. To get an accurate idea of traffic, you need constant updates, right? Imagine you counted the number of cars on the freeway at 12:05 on a Saturday afternoon four weeks ago. That’s great, but what does it tell you about traffic at 5 PM on a Thursday? Even though it’s the same stretch of asphalt/artery, we can’t divine much at all from that single measurement. You need more data points. That traffic fluctuates wildly is entirely uncontroversial. Any southern Californian could tell you that. But did you know that LDL, HDL, and total cholesterol readings in the same person can fluctuate just as wildly, oftentimes enough to move that person from “desirable” to “high risk” and back to “desirable” lipid status without any nutritional or lifestyle changes in the span of a few mere weeks?

In biology, a single snapshot rarely, if ever, tells the whole story. Who woulda known?

But just because the standard cholesterol test is but a snapshot of a dynamic system in flux doesn’t negate the potential usefulness of getting your cholesterol checked. As much as Conventional Wisdom has gotten things wrong when it comes to cholesterol and heart disease, the two do have a relationship together. There is a connection; contrary to what the AHA might think, we just don’t have it ironed out yet. In my opinion, the most persuasive hypothesis about the real causes of atherosclerosis and heart disease comes from Chris Masterjohn and is highlighted in his recent AHS talk, “Heart Disease and Molecular Degeneration,” and on his blog. It’s a synthesis of the two prevailing notions regarding cholesterol and heart disease – the one which says elevated blood cholesterol plays no causal role in heart disease and the one which says elevated blood cholesterol is the primary cause of heart disease – and it goes something like this:

LDL receptors normally “receive” LDL particles and remove them from circulation so that they can deliver nutrients and cholesterol to cells, and fulfill their normal roles in the body.

If LDL receptor activity is downregulated, LDL particles clear more slowly from and spend more time in the blood. Particles accumulate.

When LDL particles hang out in the blood for longer stretches of time, their fragile polyunsaturated fatty membranes are exposed to more oxidative forces, like inflammation, and their limited store of protective antioxidants can deplete.

When this happens, the LDL particles oxidize.

Once oxidized, LDL particles are taken up by the endothelium – a layer of cells that lines the inside of blood vessels – to form atherosclerotic plaque so they don’t damage the blood vessel. This sounds bad (and is), but it’s preferable to acutely damaging the blood vessels right away.

So it’s the oxidized LDL that gets taken up into the endothelium and precipitates the formation of atherosclerotic plaque, rather than regular LDL. OxLDL, poor receptor activity, and inflammation are the problems. But since measuring oxidized LDL in serum is difficult (oxidized LDL gets taken up out of serum and into the endothelium rather quickly) and expensive, we need other, more realistic, more obtainable methods. We need to work with what we’ve got. It would be great if a doctor could quickly order up an “LDL receptor activity” test, but I don’t see that happening anytime soon.

Enter the various lipid panels.

First up is your basic lipid panel, the standard test the average doctor is going to order for a patient. If you go this route, you’ll typically get four measurements: total cholesterol (TC); high density lipoprotein cholesterol (HDL-C); low density lipoprotein cholesterol (LDL-C); and triglycerides.

Total cholesterol

What they say: Get that TC below 200, or else (you’ll have a heart attack or you’ll have to pay a higher health insurance premium, if we take you on at all).

My take: Mostly meaningless. Even though the epidemiological evidence suggests a TC between 200 and 240 mg/dl is best for all-cause mortality, we can’t hang our hats on it. First off, total cholesterol is limited because it’s only telling us the amount of cholesterol contained in all our lipoproteins without saying anything about what kind of lipoproteins we have or how many there are. Second, total cholesterol is limited because it’s determined by a bizarre formula – HDL-C+LDL-C+(Triglycerides/5) – that reduces various types of blood lipids, each with a different role in the body and a unique impact on our risk for illness, to mere numbers. Someone with low HDL and high triglycerides could easily have the same TC as someone with high HDL and low triglycerides, so long as the numbers work out. Whether it’s being used to predict wellness or disease, total cholesterol by itself is mostly meaningless.

HDL-C

What they say: “Good” cholesterol. It’s the “garbage truck” that cleans up “excessive” cholesterol and fat from tissues, so the higher the better! Though men and women should strive for levels exceeding 60 mg/dl, above 40 is acceptable for the former and above 50 is acceptable for the latter.

My take: Higher HDL-Cs correlate strongly with better cardiovascular health. No real argument here. Higher HDLs are desirable. Just remember, it’s only a snapshot of a glimpse into the cholesterol content of your HDL particles. Among most groups tested, the TC:HDL ratio is actually a strong indicator of heart disease risk, with higher ratios corresponding to higher risks. Note, though, that no Primal Blueprint adherents were among the groups analyzed, ever.

LDL-C

What they say: Get it as low as humanly possible! I want that low density lipoprotein so low as to be nearly nonexistent. Your body obviously hates you; otherwise, it wouldn’t be producing a potently toxic substance and sending it directly into your endothelial cells to form atherosclerotic plaque! Of course, we’re not actually measuring the number of low density lipoproteins, just the amount of cholesterol contained in them, but still!

My take: While a high LDL-C may indicate a problem, remember that LDL-C only indicates the total amount of cholesterol in your LDL particles. You could easily have a few large particles (good) or a bunch of smaller, denser ones (bad, might indicate poor LDL receptor activity and an LDL that likes to hang out in the blood), but LDL-C alone isn’t enough to know. It’s also just a moment in time, whereas what you’re interested in is the trend. If the trend indicates a steady rise in LDL-C, however, that could hint at poorer LDL clearance and lower LDL receptor activity (and greater susceptibility to oxidation).

Triglycerides

What they say: Lower would be better, sure, but you really gotta do something about that LDL! Anything less than 150 mg/dl is fine.

My take: High triglycerides correlate strongly with low HDL and smaller, denser LDL. High triglycerides, then, could indicate more oxidized (or oxidizable) LDL. The triglycerides of most Primal eaters, especially those on the lower carb side of things, usually hover well below 100 mg/dl. Triglycerides come packaged in VLDL, or very low density lipoproteins (which are calculated by dividing your triglyceride count by 5).

So, what can we learn from a standard lipid test? Not much, actually. We can learn from standard lipid tests, however. If we take a series of regular ol’ lipid measurements, preferably one pre- and several peri-Primal, we can get an idea of our metabolic health. Look for:

  1. Trends – Are your triglycerides going down over time? That’s great. Is your HDL trending up? Also good.
  2. Normal fluctuations – Your numbers can jump around 20-30 points in either direction between readings without it necessarily meaning anything.
  3. TC:HDL-C ratioLower is better and indicates fewer LDL particles.
  4. Triglyceride:HDL-C ratioLower is better and indicates larger LDL (and, usually, fewer) particles. Ideally, this will be close to 1 or lower; one study (PDF) found that 1.33 was the cut off.

If you’re going to get your cholesterol tested, and the basic labs just aren’t cutting it, you might as well go for one of the premium lab tests: the NMR LipoProfile or maybe the VAP. Rather than rely on indirect estimates and formulas, NMR and VAP directly measure the  size of your lipoproteins. I find NMR to be far more useful, because in addition to measuring particle size, it measures particle count (whereas VAP only estimates the count).

But you probably have holiday shopping to do, and I don’t want to drone on for too long, so I’ll leave it at that for now. Next week, I’ll pick up where I left off and get into what you can expect from NMR and VAP testing, including the downsides and the advantages. After that, I’ll go into some strategies for improving your numbers – or, rather, improving your health which in turn should improve your numbers.

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. Hi Guys,
    Could someone please help me understand my numbers? Do I need further blood work due to my present numbers, and if so what am I looking out for? I’m a 37 yr old male, 5.8, 7.5% BF, 160lbs, 29-30 waist size, exercise regularly. Been on a paleo type diet for about a year now. Very low carb, less than 100g per day. I’m gonna give you all my numbers from before I switched from a high grain high protein low fat diet to the paleo type diet with around 9-12 ounces of animal protein per day, I switch my fats through the day, roughly one TBsp of olive oil, 1 tbsp of walnut oil for lunch, I cook all my proteins in either raw butter or coconut oil, I may have one ounce of raw almonds or 1 tbsp of almond butter raw or 1 scoop of coconut butter for a snack each day. 2 whole organic eggs per day. Lots of salads and 3 servings of steamed or sauteed greens per day. All I drink is mineral water. Please help me understand my numbers!

    High Grain High Pro/low fat diet #’s

    Total=200
    HDL=64
    LDL=99
    Trig’s ?

    6 months into paleo diet

    Total=237
    HDL=72
    LDL=122
    Trig’s=30

    12 months on Paleo diet

    Total=270
    HDL=79
    LDL=174
    Trigs=26

    Thanks for your time!
    Adam

    Adam wrote on May 26th, 2012
  2. Just got my blood test back and triglycerides were at 540…very high. I haven’t totally eliminated all sugar and grains in my diet yet, but I have reduced it. Completely stopped drinking sugared soda and changed to diet (I know, not ideal…but better than drinking the sugar).

    The LDL cholesterol was so low that he couldn’t measure it. HDL was over 200.

    Doctor wants me to get on medication. What do you guys think?

    Tommy Z wrote on July 31st, 2012
  3. Love the information! But as I live in Australia my lab results for cholesterol are not in the same value format as used in the USA. Do you have anyway to convert this?

    Cherie wrote on August 31st, 2012
  4. total : 215
    hdl: 57
    ldl: 142.60
    VLDL cholestrol: 15.40
    Triglyceride: 77
    tc:hdl : 3.77

    I have been primal for about 2-3 months. I have eaten clean for 90 p/c of the time. I had a few pizzas but it was totally within the 80-20 rule.

    Srinivas Kari wrote on September 25th, 2012
  5. I need help interpreting my blood test numbers. For reference I’m a 20 year old male who went low carb high protein February of 2012 and has been paleo for about 2-3 months. I used to weigh 155 and dropped to 130-135 with a fair amount pf running and swimming and pushups situps jump squats burpees etc. Lowered my blood pressure also. A typical diet would be
    Breakfast: two eggs, chopped onion, chopped carrot, dices tomato, handful of spinach, protein from dinner
    Snack: (2x)spinach salad with protein from dinner
    Snack: nuts, mostly almonds or walnuts
    Dinner: protein and whatever vegetable around
    My biggest concern was that my meat was normal supermarket bought. I couldn’t get my hands on grass fed. I don’t have blood test numbers pre paleo.
    TC 373
    HDL 81
    TG 61
    LDL 280
    Chol/HDLC 4.6
    Non HDL cholesterol 280
    Both my parents are on statins and I refuse to go on statins. My normal doctor is sending me to a cardiologist with pure hypercholesterolemia.
    It baffles me though. I used to NEVER exercise and would eat just about anything I wanted. I did follow the “low fat” diet but that only made me want candy, breads, white rice, pasta, etc even more. I don’t understand how losing weight and body fat while going on an all natural diet puts me more at risk for heart disease.

    David wrote on January 11th, 2013
  6. Can someone tell me if it’s possible to do a self-referral cholesterol test in Aussie? Or, do you have to go through a doctor to get one?
    Thanks!

    Sara Lake wrote on January 21st, 2013
  7. well . . my test reading for total cholesterol is 4.1, how to convert that to the other type of reading and mostly used

    Nero Seem wrote on June 10th, 2013
  8. I just got my cholesterol results and am curious about taking cholesterol medication. I’m 75, had a minor heart attack in 2006 and have had no problems since then.
    My LDL is 107, HDL 111, and Triglycerides 71. Total cholesterol is 232.
    With such high HDL and Triglycerides, why do I need to take medication? My HDL has always been high but this is the highest it’s ever been.
    Linda

    Linchad wrote on October 30th, 2013
  9. Switching to a sorta (I’m just not a good follower; I tend to synthesize things and make up my own program) Primal/Paleo/Low-Carb diet that’s fairly heavy on fatty meat (I love the taste of it!) my triglyceride/HDL ratio fell by about 75%, from normal to really, really good (about .6). So much for the CW we’ve been fed about reducing meat consumption to improve blood work.

    Karl Kelman wrote on July 3rd, 2014
  10. I am totally happy and my Doc thinks I am a superman.

    74 years of age.
    Primal for 1 year plus.
    Quit smoking 4 years ago.
    Total cholesterol ~ 171
    Triglyceride ~ 101
    HDL ~ 52
    LDL ~ 99
    Ratio ~ 3.3
    I feel grrrrate!

    Jay

    Jboy wrote on August 7th, 2014

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