Low cholesterol linked with enhanced risk of death

I saw a patient this week who occasionally feels light-headed, particularly when he stands up quickly. This symptom – referred to as ‘postural hypotension’ in medicine – usually signals that someone’s blood pressure is on the low side, and drops even lower on standing. Sure enough, his blood pressure was low (100/70 mmHg). Most doctors here in the UK like to see a low blood pressure, and often remark that this means the person has likely immunity from raised blood pressure.

I, personally, don’t have so much of a relaxed attitude to low blood pressure. First of all, pressure is required to ‘force’ blood into the organs and tissues including the brain. If blood pressure is too low, vital organs may be effectively starved of blood and therefore not function optimally. Everything in the body, be it blood pressure, sodium levels or temperature, has an ‘optimal range’. Too much of something is, by definition, a problem, but by the same token so is little (if blood pressure gets low enough we lose consciousness and can die).

Could the same be true for cholesterol? I know there’s a vogue among members of the medical profession and certain scientists to urge us to drive our levels to ever-lower levels (‘lower is better’), but does this actually make sense? Cholesterol is, after all, an essential constituent of several important entities in the body including the brain, vitamin D and ‘steroid’ hormones such as cortisol and testosterone. If blood cholesterol levels get low enough, could this starve the body of essential element and therefore jeopardise health?

While ‘raised’ levels of cholesterol are associated with an increased risk of heart disease, lower levels of cholesterol are also associated with an increased risk of cancer as well as ‘haemorrhagic stroke’ (strokes caused by bleeding in the brain). These observations do not mean that low cholesterol causes cancer or stroke (neither do they mean that cholesterol causes heart disease either).

In order to get a best overall picture of the relationship between any factor and health, it makes sense to assess its relationship with overall risk of death – also known as overall mortality.

Previous evidence has revealed that while higher cholesterol levels may be associated with increased overall mortality in younger individuals, this trend reverses as people age. The relevance of this is that most individuals die when they are advanced in years, and therefore the relationship cholesterol has with overall mortality in the elderly is, generally, much more relevant and important than this relationship in the young.

A recent study illustrates this [1]. In it, researchers examined the relationship between overall mortality and individuals aged 60-85 (average age 71) over a period stretching 12 years. Initial analysis revealed that higher total cholesterol levels (> 200 mg/dl/5.2 mmol/l) were associated with a 24 per cent reduced risk of mortality over the study period. And lower cholesterol levels (< 170 mg/dl/4.4 mmol/l) were associated with a 60 per cent increased risk of death.

Some claim that the association between lower cholesterol levels and increased risk of death is due to the fact that when individuals are ill or frail their cholesterol levels tend to be low. In other words, the heightened risk of death is due to the illness and/or frailty associated with low cholesterol, not the low cholesterol per se.

To adjust for these so-called ‘confounding factors’ the data was reanalysed, this time after removing individuals who were low in weight (BMI < 20) and/or who died within 2 years of the analysis starting. Once these adjustments had been made, the relationship between raised cholesterol and lower risk of mortality was no longer statistically significant. However, the relationship between lower cholesterol levels and increased risk of death remained (36 per cent increased risk).

Again, epidemiological studies of this nature do not tell us if the relationship between lower cholesterol levels and reduced survival is ‘causal’. However, this sort of evidence should at least cause us to pause before we recommend that individuals, especially elderly ones, drive their cholesterol levels to ever-lower levels (like some would have them do).

References:

1. Sarria Cabrera MA, et al. Lipids and all-cause mortality among older adults: a 12-year follow-up study. Scientific World Journal Epub 1 May 2012

18 Responses to Low cholesterol linked with enhanced risk of death

  1. Kim 11 October 2012 at 5:26 pm #

    I have very low cholesterol and it seems the better I eat, the lower it goes. When I eat a junk food diet, it’s around 150 total cholesterol and when I was on a low carb diet consisting of mostly meat and vegetables and went as low as 108. The last time I had it checked after being on a low carb primal diet consisting of meat and vegetables, some cheese, plenty of butter and bacon, it measured about 128 total cholesterol. Granted my hdl had improved somewhat and was up to 47 and my triclyderide was 35, it still worries me that my cholesterol is so low eating a healthy diet. I avoid higher carbs as I had T2 diabetes before starting the primal diet.

  2. lucy 12 October 2012 at 1:21 am #

    I also have very low blood pressure, and notice that if I sleep with my hands on top of my belly (slightly raised), or am working on something that involes my arms being raised above my head, they quickly go numb.

    Is there anything I can do to raise it, naturally?

    Any links to articles that you may have written on the subject?

    Thanks.

  3. roy harvey 12 October 2012 at 12:39 pm #

    Dr Briffa. Hi i am torn between taking statins or not. i am 67 have diabetes 2 and high blood persure i go for a speed walk every other morning at 70clock am and i feel fit. i have lost a stone in weight doing a fast for 2 days a week , when i stoped taking statin tablets my colesterol went up to 5 and my doctor wanted a word,! by phone am i right in not taking statins confused.

  4. Lorna 12 October 2012 at 3:23 pm #

    Wondering about the last paragraph: ‘lower cholesterol levels… enhanced survival’. Shouldn’t this read ‘higher cholesterol levels … enhanced survival’?

  5. Dr John Briffa 12 October 2012 at 4:39 pm #

    Thanks Lorna – corrected now.

    John

  6. Georgia Ede MD 12 October 2012 at 4:44 pm #

    Such an important post. Most cholesterol drug trials are conducted as if human beings consisted of a heart in a test tube, ignoring effects on overall health. It has long been known that there is an association between low cholesterol levels and suicide, although the reason for this apparent connection remains unclear. Most studies were, naturally, epidemiological in nature, and therefore it is impossible to know whether low cholesterol itself causes suicidal tendencies. There have been some interventional studies using cholesterol-lowering medications, most of which have shown the same trend, but the problem there is that the medications themselves can sometimes cross the blood-brain barrier and cause psychiatric side effects, so again, we don’t yet know what’s really going on. However, it stands to reason, as you point out in your post, that low cholesterol levels could be hazardous to our overall health, given cholesterol’s critical biological role in every single cell of our bodies. Cholesterol comprises 15% of the dry weight of the brain. 20% of the body’s cholesterol is found in the brain, where it is an integral component of membranes, synapses, and myelin sheaths. How could the brain function properly without it?

    Zhang J. Epidemiological link between low cholesterol and suicidality: a puzzle never finished. Nutritional Neuroscience 2011; 14(6):268-287.

  7. lorraine cleaver 12 October 2012 at 4:47 pm #

    I’m unsure what this means really. My cholesterol was high when hypothyroid but has come down to the perfect numbers now, according to GP, now that my thyroid is finally properly medicated. Does this mean it was better for me to have it remain high at 6?

  8. John Walker 12 October 2012 at 5:54 pm #

    I am unsure of my cholesterol levels. In the late eighties, I was hovering around 5 (Whatever units they use), and then it was average and ‘all right-no worries’. These days that reading is considered high. What’s changed? I doubt the human physiology has changed, so someone moved the goalposts maybe? I wonder, because I’ve read no convincing explanation for the change in acceptable levels. So I don’t worry about cholesterol. On a low carb diet one can’t anyhow, and of course, if I don’t eat enough cholesterol my liver manufactures it. I am reminded of something I saw somewhere. Why is there so much cholesterol in an egg? Because an egg has to have all the building-blocks to make a chicken. Makes sense to me..

  9. helen 13 October 2012 at 3:32 am #

    ^John, the medical establishment are always shifting the goal posts, blood pressure, weight and cholesterol to name just three………..any time any one tells you that you are above or below average well honestly what does that mean?? it means they have selected a random number and decided that it will be the benchmark and it seems to be subject to whatever drug or food or treatment they are pushing at the time to get maximum coverage of the population and thus increase their bottom line…………not rocket science just follow the money…….I am what they would term obese and while I could lose a few pounds I am very healthy I never get sick and I always expect myself to be thus ….(and so it is!) unlike my super skinny friends & normal weight co workers who are always sick and cant understand why I am not……….I never take someones subjective normal as my own what is normal for you may not be normal for me and vice versa the same goes for everyone. When they get back to treating everyone in a holistic manner then I will think there is some hope for people not to be so sick but when they keep telling us to eat things that increase the risk of getting diabetes, cancer and other chronic illness it beggers my belief …………thank the powers that be that people like Dr Briffa and a few other medical souls who look, observe and question constantly and come to informed conclusion that actually help individuals …………the medical establishment seem to see us all as cash cows and instead of treating the person lump us all into the same pile of illness ………then look at only cures rather than prevention and play the FEAR card to get us to conform…………all advertising does this no matter what it is for ……..makes us scared we arent good enough or well enough or pretty enough or what ever and then SELLS us the cure………….have a look at every commercial and you will see that it isnt sex that sells it is fear …………ask a marketing manager and if they are honest you will understand this to be true……….make the punter feel frightened or afraid of being left behind and you can sell them anything to make them feel better.

  10. Gregory Barton 13 October 2012 at 7:12 am #

    Well said, John. The “one size fits all’ recommendation for cholesterol levels, regardless of age, ignores the fact that cholesterol forms part of the innate immune system. As we get older and accumulate more pathogens it makes sense that we need more cholesterol.

    But Lorraine Cleaver raises a good point. The fact that her LDL-C is lower due to thyroid supplementation indicates that cholesterol is being cleared from the blood and utilized to make hormones, bile acids and other goodies. So the lower number doesn’t necessarily indicate that she has less cholesterol. It merely indicates that there is less cholesterol (or fewer lipoproteins) in her blood.

    Low cholesterol could therefore indicate cholesterol is being utilized, rather than indicate a deficiency.

  11. PeggyC 15 October 2012 at 1:50 am #

    @Roy Harvey, Have you at least tried to control your diabetes with a low carbohydrate, high fat diet? As Dr. Briffa recommends repeatedly? Fasting two days a week is easier if the rest of the time you are low carb high fat. And that could correct your cholesterol numbers as well, without statins. And total cholesterol is less predictive than certain ratios, triglycerides to HDL (lower than 2 is best) for one. I”m not a doctor, so I’ll leave the “should I take statins” question to Dr. Briffa, but I wouldn’t take any drug without first trying to fix things with diet. A low carb, grain free diet is good for both T2 diabetes and cholesterol!

  12. Gregory Barton 15 October 2012 at 5:38 am #

    Roy, if I had cholesterol of 5 mmol/l, or 193 mg/dl (which I do) I wouldn’t want it to be any lower.

  13. Gregory Barton 15 October 2012 at 5:46 am #

    Oh, by the way, you might be interested in referring to this chart:
    http://perfecthealthdiet.com/wp/wp-content/uploads/2011/06/O-Primitivo-Cholesterol.jpg
    It’s in mg/dl. But you can convert the numbers using this website:
    http://www.onlineconversion.com/cholesterol.htm

  14. Lorna 15 October 2012 at 10:59 pm #

    ‘lower cholesterol levels and increased risk of death is due to the fact that when individuals are ill or frail their cholesterol levels tend to be low’.
    If this is true, wouldn’t it suggest that high cholesterol indicates better (not worse) health?
    Why is ‘healthy’ being so frequently re-defined: better research or is it a way to gain publicity for ‘new’ treatments/drugs? What was acceptable a few years ago is now demonised in terms of cholesterol levels. If you look at what happened to HRT, the press does not report it as such a ‘wonder’ drug any more. Why? It would be useful for the popular press to alert us to why drugs come in and out of popular prescription/use rather than the constant search for the new, the scarey and the profitable.

  15. alan 17 October 2012 at 6:15 pm #

    i too have a blood pressure of 100-60. i do quite a lot of running cycling. still, i am not sure if it is regular or not optimal, although i do not experience the normal symptoms tied to it

  16. Doc´s Opinion 18 October 2012 at 12:17 am #

    This research reflects our limited understanding of the role of cholesterol in health and disease. We know that cholesterol is necessary for health, and we know that without cholesterol atherosclerotic heart disease as we know it would not exist.
    So high levels of cholesterol may indeed reflect good health, for example in the elderly. People who grow old with high cholesterol are probably protected somehow, maybe by unknown mechanisms. Therefore, the significance of total cholesterol may often be very difficult to interprete and obviously high cholesterol does not go hand in hand with bad health.
    Fortunately we are gaining more understanding about the role of blood lipids in atherosclerosis. LDL particle size and particle number (LDL-P) appears to be strongly associated with risk: http://www.docsopinion.com/heart-disease/ldl-p/. Therefore, total cholesterol might not be used for much longer as a treatment target to reduce the risk of heart disease.

  17. Paul Anderson 19 October 2012 at 10:23 pm #

    It (total cholesterol) probably will continue to be measured simply because its far cheaper than measuring the various sub particles of cholesterol. And what improves the profile of cholesterol, away from the small dense LDL to the large fluffy type: saturated fat. It also raises the so good good cholesterol, HDL.

    If you wanted to look measure something that was a good indicator of longevity and future good health, and give yourself a good chance of avoiding heart disease and quite possibly cancer further down the road, a far better indicator, in my opinion, would be keeping an eye on your HbA1C measure. And how would you keep this low: I would suggest avoiding a diet high in processed carbohydrates, sugar and quite possibly starches.

    Paul Anderson.

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