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What is cholesterol?

What is cholesterol?
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I know much more about cholesterol today than I did even two years ago, let alone when I was mindlessly reiterating “standard” cholesterol recommendations to patients years ago.   You can’t talk about nutrition without mentioning cholesterol, but most folks (including many of the doctors who tell you yours may be too high) don’t know what cholesterol actually is, let alone the actual risk it portends.  I’m going to be doing a lot of writing about the confusion over cholesterol in the future, but I want to very quickly give you a few things to consider.

    1. Cholesterol is a “waxy” substance generally produced by our liver.  Without we could not live, which is to say cholesterol is vital for many functions in our body.
    2. There are many types of cholesterol particles that vary by size, density, and function
    3. More often, what people mean when they say “cholesterol” is “lipoprotein,” and these are not the same thing. I’ve tried resisting the urge to include this figure, but I just can’t help it.  Below is a figure of a lipoprotein particle.  Hopefully you can make out that cholesterol is a part of the lipoprotein, along with other molecules like triglycerides (TG), cholesterol esters (CE), phospholipids, and apoproteins.

lipoprotein particle

  1. As you’ve probably heard, there low density lipoproteins (LDL), high density lipoproteins (HDL), and a few variants in between of intermediate and very-low density, respectively (i.e., IDL, VLDL).
  2. Historically, we’ve been taught that LDL is “bad,” while HDL is “good.”  This is true in the same way it’s true to say rugby is safer than football, because they don’t wear helmets and don’t hit quite as hard.  It sort of misses the important nuances (which I won’t go into here).  Unfortunately, it’s far too simple to assert that LDL is “bad,” though it is easier to say HDL is “good.”
  3. The aspect of LDL that makes it “bad” is not the cholesterol concentration (the so-called LDL-C, which is what your doctor measures when you get a cholesterol test), it’s probably the actual particle itself (the so-called LDL-P, which you never get checked unless you have a fancy test called a lipid nuclear magnetic resonance – or NMR for short – test).  If that doesn’t confuse you enough, this might: there are different types of LDL molecules, which vary in size.
  4. As a general rule, ceteris paribus, the smaller the LDL particle, the more damage it causes.  This is actually a bit controversial.  There are some (pretty smart folks) who make the case that a particle of LDL is a particle of LDL – it’s only the number of them that matter, not the size.  In other words, the only thing about LDL particles that matter is their number, not their size or the concentration of cholesterol within them.
  5. Confusing this even more, in about a third of folks, LDL-C (the concentration of LDL cholesterol) and LDL-P (the number of LDL particles) are actually what call discordant (i.e., not predictive of the same thing)
  6. Our entire belief that high LDL-C is “bad” stems from the following logic: taking a type of drug called a statin lowers LDL-C and lowers risk of heart disease, ergo high LDL-C must be “bad.”  The problem with this logic, I hope you can see, is that it negates the fact that the benefit of statins could result from doing something other than lowering LDL-C.  I personally am not convinced that statins exert their protective benefits by reducing high LDL-C.  I believe they reduce, specifically, the number of small particles and overall inflammation, and that these effects are likely what confer their benefit.  More about this later.
  7. While HDL is considered “protective,” it’s not uniformly true.  There are actually many different HDL particles (of course, the standard test only measuring the concentration of cholesterol in HDL, denoted HDL-C).  If that weren’t bad enough, different technologies (e.g., VAP versus NMR) actually use different nomenclature to describe the different subparticles of HDL.  As a general rule, the larger the HDL particle, the more mature it is, the more protective it is.  HDL particles are probably protective for two reasons: 1) they can enter and exit the artery wall without causing damage, unlike the LDL particle, and 2)  they can carry damaging particles called oxysterols from the artery wall back to the liver via process called “reverse cholesterol transport” or RCT.
  8. Triglyceride (TG) levels in the blood are better when “low” than when “high.” Of course the cutoff that constitutes “high” is debated.  Standard tests suggest an upper limit of 150.  The real whizzes on the topic actually suggest TG levels should be below 80.  In fact, combining HDL-C and TG into a ratio (i.e., TG/HDL-C) is probably the single best predictor of cardiac risk you can derive from a standard cholesterol test.  The lower the ratio, the lower your chances of having an “adverse cardiac event,” as the medical community describes it (e.g., a heart attack).

…and that was short version of Cholesterol 101.

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About the Author:

Peter Attia, M.D., is the co-founder and President of the Nutrition Science Initiative (NuSI), a non-profit based in San Diego, CA. He received his B.Sc. from Queen's University in Canada and his M.D. from Stanford Medical School in California. After his surgical residency in general surgery at Johns Hopkins he worked as a consultant at McKinsey & Company. He founded NuSI with scientific journalist Gary Taubes in 2012.

Discussion

  1. auto-rijbewijs  December 29, 2011

    It’s a nice blog you have over here! It’s very usefull information for me and I just want to thank you for that! If you post more threads as this one, I’ll follow your blog active!

    (reply)
  2. Dorian  February 7, 2012

    Peter,
    I have upcoming blood work and am considering asking for an NMR or VAP test — neither of which I’ve had before but hope to track going forward. Would you suggest one over the other? Also, do you know if there tends to be a major cost difference between these two tests?
    Thanks!

    (reply)
    • Peter Attia  February 7, 2012

      NMR is the gold standard and more valuable than VAP. The reason is that only NMR can “count” the number of LDL particles which is actually what matters (rather than just the amount of cholesterol they hold). Cost is a function of insurance, typically.

    • RGoodin  February 21, 2012

      I recently had a VAP test and it does give a “Real-LDL size pattern” which showed mine to be Large Buoyant, Pattern A LDL. It’s not a specific count, but if it’s reliable, it gives an indication of the Pattern size which could be helpful.

      It also gave my “Real-LDL cholesterol” as 147 and my “Sum Total LDL-C” as 164. The TG/HDL-C (66/83) was 0.8.

      I thought the test was useful, but haven’t had a NMR done.

    • Peter Attia  February 21, 2012

      I’ll write more about this in a subsequent post. All of these measurements are indirect, though. LDL-P is the most important number.

  3. Dennis in Canada  March 14, 2012

    Nice explanation of cholesterol. I’m wondering however, what is an acceptable range for the TG/HDL-C ratio?

    Secondly, how meaningful are the LDL-C numbers and the HDL-C numbers. For example, can it be normal for a person to have low TG, normal HDL-C and high LDL-C? I mean this would yield a good TG/HDL-C ratio, but a high total C.

    I guess what I’m asking, in the face of conflicting numbers, which ones should a person focus on?

    (reply)
    • Peter Attia  March 14, 2012

      Dennis, great questions. All will be answered in time, but if you need to take away one message, make it this: NOTHING matters once you know LDL-P. Find that out and get it fixed. All the other stuff we try to use to help us estimate.

  4. Debbie  April 1, 2012

    Hi Peter,

    If you’ve written about cholesterol levels in depth, I apologize for asking these questions in advance. But, as per your response to Dennis, how does one fix a too high LDL, aside from adhering to a low-carb diet, which of course I am doing? I haven’t had my cholesterol levels checked in about six months, since I began the diet – frankly, I’m scared to. I always had low LDL, and high HDL; suddenly, these were reversed. (I got a rushed call from the doctor’s PA, asking for my fax # so she could send over a statin prescription – which I rejected – I hope politely – but I doubt it.) So, I’m hoping the next blood test will show an improvement in these numbers. But, let’s say they don’t – I always assume the worst – then what?

    Thanks again,
    Debbie

    (reply)
    • Peter Attia  April 1, 2012

      Don’t sweat LDL-C (LDL cholesterol). The number is almost meaningless. All that matters is LDL-P (number of LDL particles). The problem, unfortunately, is that most doctors don’t know this, so they just order standard lipid panels. PLEASE — and I write this for EVERYONE — insist to your doctor that you have a lipid NMR test done. I will write about this is great detail soon. Hopefully, it will be “good” enough to share with your doctors.

    • Debbie  April 2, 2012

      Thanks, Peter. By the way, I finally found red meat I love: corned beef! I had a giant sandwich at a place here in New York on the famous lower east side – without the bread, of course – and a side salad. Unreal! Supposedly, it was 1/3 lb. of meat, but, I don’t know… it looked closer to a pound to me… this way of eating can be just fine. (You may wonder how I could have missed out on corned beef and pastrami, but all I ever had an interest in was SWEET STUFF. And corned beef was supposed to be bad for you anyway. Well, I can make up for lost time) :)

      Debbie

  5. Diana  December 4, 2012

    Discovered the Atkins diet about 15 yrs ago and realized that all calories are not created equal. It is nice to see that someone else is finally picking up the ball. Thanks for all your hard work.

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  6. Elizabeth  February 13, 2013

    Hi Peter,
    I just happened to come across your site while looking up info on my recent lab work. I know you cannot provide medical advice, but am curious as to what you would do in my situation. You seem to have the only site that addresses more than just the lipid levels.
    I am a 30 year old female with a history of high LDL and Triglycerides since a teenager. I went to a doctor a few weeks ago because of what I felt might be heart related issues. He ordered blood work and I just got the results in. After reading your comments, I am just going to give the LDL-P for now, and see what you think. The total was 2673. The recommendation I got was a low carb, low fat, low cholesterol, low sugar diet. Any suggestions?

    (reply)
    • Peter Attia  February 13, 2013

      Impossible to give dietary recommendation based on just LDL-P. Even if I were in a position to give advice in this capacity, I would need to know much more before doing so. Presumably a low carb, low sugar, low fat, low cholesterol diet it doing to do more good than harm, but what, exactly, will you eat? This is a pretty hypocaloric diet, which is likely not sustainable for very long.

    • Elizabeth  February 13, 2013

      Thank you for such a quick response. I too have been concerned about what I’ll be able to eat. It seems like that pretty much eliminates everything! I have always considered myself as having a fairly “healthy” diet. Especially compared to my husband who has great levels.
      My lipid numbers were: TC 263, LDL-C 120, HDL-C 55, TG 324, Non-HDL-C 208. (These have been steadily creeping up over the past few years) I am also going to include the Apo B:Apo A-I Ratio : 0.96 and Insulin: 14.
      The doctor’s office just gave me the results, and said to make a diet change. Would you recommend seeing a nutritionist?
      I don’t really know where to start, or if I should be alarmed at this point.

    • Peter Attia  February 15, 2013

      You need to see a good lipidologist, not just a general doc who prescribes meds to everyone who walks in the door. Your TG is very high.

    • Elizabeth  February 15, 2013

      Thank you! I think what you are doing is wonderful. I hope you continue to educate people. Good luck in all your endeavors.

  7. Michelle L.  June 26, 2013

    Thank you for an interesting article. I was telling my co-worker about high-fat, low-carb diets and she was concerned about the affect of cholesterol. I guess I am wondering two things:
    1) should she be concerend? If not, why not?, and;
    2) I am interested in incorporating smaller amounts of complex carbs, such as oatmeals, into a moderately-high fat diet. I see that you dont do this at all. Will doing this cause me to gain weight and have other health problems.
    This is all very new to me and I just want to have a healthy, sustainable diet.
    Thank you.
    Michelle

    (reply)
    • Peter Attia  June 27, 2013

      Michelle, see (or direct your co-worker) to the series I wrote on this, The Straight Dope on Cholesterol (9 parts and counting). Short answer: no.

  8. Chetandeep Singh  June 30, 2013

    Great source of Knowledge challenging conventional wisdom. My context:- I am a weight loosing spree. I have lost 10 pounds in last 2 months – nothing to boast of (neither do i want to). All i did was in last 2 months, eliminated added sugar by 80% from my diet – 0 sodas, no cakes, pastries, sugarless tea etc. After watching your TED talk & going through your website, I feel energized to take this to the next level – being fit. Having a family history of diabetes & cholesterol, the motivation to change is compelling. My question:- Since the conventional lipid profiling is not much of a use & so on, to start with, what tests should I ask my physician to order for me ? Thanks for sharing all the knowledge with us.

    (reply)
    • Peter Attia  June 30, 2013

      Slow and steady is the name of the game. See the series on cholesterol for the tests.

  9. Jacob Rea  June 30, 2013

    Over the past 6 years I have lost 200+ pounds (by way of gastric bypass) and have gained about 95 of those pounds back. Here as recently as 3 months ago I did the HCG diet with daily injections, weekly doctor visits and increased exercise. I lost 45 pounds in 6 weeks. Anyone with weight problems would be pleased but once off the diet and injections, my weight started coming back despite keeping to a modified diet.
    After viewing your TEDMED talk, you have given me hope. After watching (at 6 PM) I spent the next 9 hours researching your website, other physician’s writings and short films on protein diets and am starting down this path to hopefully achieve good and permanent weight loss.
    I viewed your snapshot of a daily meal… I am wanting to follow something close to that but what does one do who is lactose intolerant? I can eat hard cheeses and a few soft cheeses, but creams and milks makes me feel like I am being choked and shortly thereafter, I am in the bathroom eliminating almost everything in my gut.
    I need a constant supply of energy day and night. By day I do coordinate a Cancer Research study and by night I am a cross between a Chiropractor and massage therapist. My day job taxes my brain, my night job is purely physical as I help professional athletes keep their bodies in as close to perfect running order and without a constant supply of energy, I can’t help those who depend on me.

    (reply)
    • Peter Attia  June 30, 2013

      Jacob, I’m not sure following my diet (which is constantly changing, by the way) is necessarily right for you. I would suggest small, but sustainable changes for ~8 week periods. Perhaps eliminate sugar/HFCS for this period of time (which also improves the glycemic index of your carbs), as a first step?

    • Jacob Rea  June 30, 2013

      Thanks for your advice and time both are greatly appreciated. – Jake

  10. Julie Hopkins  August 15, 2013

    My husband and I began an (initially) ketogenic, then very low-carb journey at the very end of 2012. He had become a full-blown type 2 diabetic, and I was feeling absolutely horrible on statins. He is now completely controlling his diabetes with diet … his blood sugars are terrific and he’s much more insulin sensitive now. His lipid profile is being done tomorrow.

    I have gone from a size 12 to a 6, my blood sugar is perfect, and my blood pressure which had begun creeping up is perfect. My lipid profile results are in, and I have gone from a total cholesterol of 220 while on a statin to 354 now/not on a statin. However, my triglycerides have fallen from 200+ to 176, and my HDL-C has gone from 34 to 47. I appreciate this article referencing the importance of the TG/HDL-C ratio, and mine has gone from 5.9 to 3.7. I will request an NMR Lipid Profile before going back on a statin, but I am wondering what is considered a “good” TG/HDL-C ratio?

    Thank you! Your articles are wonderful and we appreciate your intellectual curiosity and the wealth of information you present in an accessible way.

    (reply)
    • Peter Attia  August 15, 2013

      Depends who you ask. If you ask me, TG/HDL-C is ideally below 1 (when both are measured in mg/dL) when most insulin sensitive. Most doctors are happy if less than 3.

    • Bill  August 15, 2013

      “TG/HDL-C is ideally below 1″

      My most recent fasting TG/HDL is 0.14 (23 TG mg/dl / 162 mg/dl HDL). Fasting blood glucose 87.

      Not a lab error—consistent with previous tests.

      I eat low carb, but not ketogenic, not VLC.

      Safe to assume I’m insulin sensitive? I ask because while I am lean, I have some subcutaneous belly fat I did not have when I did eat VLC.

      I’ve been wondering why a modest amount of carbs would make me less lean if I am insulin sensitive. I see many Vietnamese people in my city of all ages who eat tons of rice and noodles and are super-lean, I imagine because they are insulin sensitive and carb-tolerant, like the Kitavans, etc.

  11. Bert  September 17, 2013

    Just found your site. Awesome. Ah, item 5 of “What is Cholesterol?” doesn’t have a period at the end of the sentence. Sorry, it’s who I am. I’ve learnt to except it and I try not to bother others too much with it. Thanks again for the information.

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  12. david  April 2, 2014

    I agree with, as far as I can tell, everything you say. My diet and exercise program weren’t that far off from yours, although at age 70, I bit less intense I’d imagine. But still, trekking 8 hours a day for weeks in the Himalayan foothills, swimming, hiking, tai chi, pretty intense weight workouts. I could jump in the air and with both feet off the ground kick over my head with the other leg, and then land softly. Happy days.

    I got a statin jammed on me by a couple of MDs. First opinion and second opinion, the second a cardiologist with complete ignorance of Apo B: I asked him about it and he said “”The science isn’t there yet.” Six months on low-dose simvastatin and I can’t walk around the block: a neuromuscular disease. Fasciculations, shocking muscle atrophy, continual burning and cramping in the feet and legs. You wouldn’t believe the photos of what happened–though I’d be glad to share. It’s been two years now, and from the reports of others, not much hope.

    My question: do you know of any research being done into statin-triggered diseases like mine…and that of thousands of others? I never had a cholesterol issue: I had an LDL-C number that…well, before my doctor wanted it under 100; but miraculously, that number’s been raised to 190. (Dr Nissen, Cleveland Cline: “They’re making up these numbers out of the air.”

    Okay, I was extremely healthy, but now I’m not. Is there any hope for treatment anywhere you know?
    David

    (reply)
    • Peter Attia  April 2, 2014

      No doubt, statin can have complications, which it sounds like you had. I’m sure hoping they immediately pulled the medication away from you.

  13. gerard hughes  April 6, 2014

    i have been told that my levels of triglycrides are high 3.1 when it should be under 1.8
    my doctor revered me to your website for info can you suggest what i should do
    re diet . i am 56 male and fairly good health
    regard gerry hughes

    (reply)

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