When it comes to cholesterol, is lower really better?

Very few of us will not have noticed that the last couple of decades have seen a concerted effort from health agencies and health professionals to persuade us that we should be driving our cholesterol levels to lower and lower levels. When I was at medical school the upper limit of cholesterol was 6.5 mmol/l (255 mg/l). But it’s come down steadily since then and now stands at 5.0 mmol/l (195 mg/l). My suspicion is that it will fall even lower over the years. Who knows, it may get so low that practically everyone will be classified as having a raised cholesterol, and be recommended to lower this with specialised food products and/or drugs.

However, seeing that cholesterol is a constituent in the walls of cells in the body as well as what are known as ‘steroid’ hormones, there is an argument for questioning whether lower really is better. Some have suggested that low levels of cholesterol may predispose to health issues including those that relate to brain function.

Last month saw the publication of a study in the journal Neurobiology of Aging in which Dutch researchers assessed the relationship between cholesterol levels and mental function in about 1200 individuals aged 65 or older. The participants in the study were assessed over a 6-year period. Lower cholesterol levels in this group were associated with a reduction in both general cognition and information processing speed. The authors of this study concluded that their results indicate that: �lower total cholesterol may be considered as a frailty marker, predictive of lower cognitive functioning in elderly.�

Of course with studies of this nature, it is impossible to know whether the low cholesterol is responsible for the associated poorer brain function. However, one way to assess this might be to attempt to lower cholesterol levels and see what it does to brain function. In one study, individuals treated with lovastatin (a cholesterol-reducing drug), compared to those taking a placebo, saw significant reductions in measures such as vigilance and general cognitive function [2]. This study, though, did also test the effect of another statin drug (pravastatin) which did not appear to have this same adverse effect on brain function.

Even if we take the apparent association between lovasatin and impaired brain function as face value, we do not know whether this was due to cholesterol lowering per se or, say, some side effect of the medication.

Another study, though, does add further evidence to support the notion that lower cholesterol levels may impair brain function. In it, a low fat diet was pitted against a standard diet over a 12-week period [3]. The performance of a task that required sustained attention was significantly worse in individuals who had reduced their cholesterol over the course of the trial. And the lower the cholesterol fell, the worse the performance in this test was.

Even if it turns out the cholesterol reduction is bad for the brain, I have no doubt that proponents of the cholesterol concept will point to other benefits of this endeavour. Though I do think it is worth bearing in mind that the evidence shows that in essentially healthy individuals, cholesterol reduction through drugs has not been shown to save lives. And dietary approaches do not appear to reduce funeral rates either, even in those with a history of cardiovascular disease.

And finally, there is at least some evidence that in later life, higher levels of cholesterol are actually associated with enhanced longevity [4-7]. There is mounting evidence, I think, which suggests that as far as cholesterol is concerned, lower is not necessarily better.

References:

1. van den Kommer TN, et al. Total cholesterol and oxysterols: Early markers for cognitive decline in elderly? Neurobiol Agin. 2007 Sep 19; [Epub ahead of print]

2. Roth T, et al. Comparative effects of pravastatin and lovastatin on nighttime sleep and daytime performance. Clinical Cardiology. 1992;15:426-432

3. Wardle J, et al. Randomized trial of the effects of cholesterol-lowering dietary treatment on psychological function. Am J Med 2000;108(7):547-553

4. Brescianini S, et al. Low total cholesterol and increased risk of dying: are low levels clinical warning signs in the elderly? Results from the Italian Longitudinal Study on Aging. Journal of the American Geriatrics Society 2003; 51(7):991-996

5. Forette B, et al. Cholesterol as risk factor for mortality in elderly women. Lancet, 1989; 1:868-870

6. Jonsson A, et al. Total cholesterol and mortality after age 80 years. Lancet, 1997;350:1778-1779

7. Weverling-Rijnsburger AW, et al. Total cholesterol and risk of mortality in the oldest old. Lancet, 1997;350:1119-1123

11 Responses to When it comes to cholesterol, is lower really better?

  1. Anne Larvin 11 October 2007 at 2:16 pm #

    I’d be interested in your take on today’s front page (virtually WHOLE page) headline and write up saying that statins are a miracle pill that work even years after you stop taking them.
    There are some very powerful lobbyist out there, and some pretty shoddy journalism going on – e.g. the recent appalling piece in many of the papers about indvidualised herbal medicines not working.

  2. Sara Neill 12 October 2007 at 4:31 pm #

    Although I reckon my cholesterol level, at under 6, is quite good for a woman of 63, I have been under pressure from my G.P. and others to take statins for several years now. I won’t, so I’m glad to have my isntinct supported by evidence at last.

    I agree that there appears to be a trend towards driving these figures ever downwards. Indeed, the same seems to apply to blood pressure levels. Again, I think mine is reasonably good; lower than what used to be regarded as O.K for my age, but it isn’t low enough for my G.P. He wants me to take drugs to lower that, too.

    But I know that I only have to see a doctor these days for my blood pressure to rise steeply – the rest of the time it’s O.K.

    I sometimes think it will come to a point at which the health industry specifies for each condition (and others) one, very specific level as “healthy” with anything under or over that level needing drug therapy. This even though both these levels fluctuate as part of a normal, healthy metabolism, so no single test can give a realistic idea of where a person’s BP or cholesterol levels stand over time.

    To save ourselves I think we must all maintain a healthy scepticism, and questioning attitude, to what we are told is good for us.

  3. Richard Trim 12 October 2007 at 7:56 pm #

    This is a midly light hearted response.. I’m just wondering having read your piece on cholesterol levels whether it’s better to to be alive and kicking and brain dead …or to be bed bound by poor heart function but have a brain that can do sudoku but can’t hold the paper or pencil.

  4. Tiggy 13 October 2007 at 1:31 am #

    The pharmaceutical industry wants statins sold over the counter and given to children as well. They reckon half the population need statins!

    My parents are both on them and it’s really affected their memory and other cognitive abilities. Now, even though my dad’s doctor says his cholesterol is okay, he’s keeping him on statins.

  5. lucille helman 13 October 2007 at 3:26 am #

    For most of my life I have been on a low salt and sugar and fat diet. I eat fish and chicken and nut butters because I can’t have whole nuts. In the past few years I gained weight. When I went for an angiogram due to pain(which I realized was chest muscles) the doctor was surprised that I had no obstruction in my veins at 78 years of age. I am taking statins because my cardiologist wants my levels to be at 100, it was 167 in the spring. I had brain fog three months ago and called the cardio and neuro doctors regarding the meds they prescribed. I made the neuro dr. give me (HupA) 50 mg. 2 x’s day.-Made by Solaray.My mind is much clearer and I retain new info well. Be proactive and take care of yourself-not the doctor!

  6. Hilda Glickman 13 October 2007 at 10:26 pm #

    AS far as I know cholesterol has important jobs to do in the body and just being in the blood is not enough for it to be a danger. Being in the blood and clogging up the artery walls are two different things. Also it appears to be oxidised cholesterol which is the problem rather than cholesterol per se. It is nutrients such as cholin inositol and B6 and magnesiium which keep cholsterol at normal levels. Lecithin breaks down cholesterol into tiny particles which can pass into the tissues rather than getting stuck in the artery wall. Lecithin is made of fat, cholin and inosital (Adele Davis) .unsat fat and coenzymes B6 and magnesium. So it seems that it the way in which the body utilises the cholesaterol it has that matters.i

  7. Hilda Glickman 13 October 2007 at 10:43 pm #

    P.s. Anyone worried about heart disease should have their homocysteine tested . (York test labs)

  8. helen 14 October 2007 at 10:29 pm #

    Women should note that even on the DRUG COMPANY WEB SITES buried amongst all the hype on their statin drugs they do admit that these drugs have absolutely no benefit to women elderly or middle aged & that the only real health benefit seems to be for men of ages 50 to 70 who have already had heart attacks or been diagnosed with heart disease. So unless you fall into this category statins have absolutely no use to your continued health instead they increase the risk of overall death from things like cancer, & yes heart problems! all this information is readily available in the drug company research however once the spin doctors are done with it you would never know you were reading about the same drug. Just remember the best cure is not getting sick in the first place PREVENTION is something that medicine seems to have forgotten about in the huge rush to find that magic little pill & replacing vitamins & minerals which are natural to our bodies with drugs & harmful chemicals will never take the place of real medicine. Doctors have unwittingly become nothing but drug pushers for the pharmaceutical companies. Makes you wonder where the world’s health is going to end up doesn’t it? When money & economics becomes more important than common sense & natural health enhancement.

  9. Norma Laming 22 December 2007 at 3:46 pm #

    But what do you do when you get to the age when your GP and hospital doctor test your cholesterol levels? I haven’t got to this point yet but how does one resist efforts to lower cholesterol levels? It really is hard to say no, particularly if you have a chronic medical condition. One comes across as a crank, which is bearable, but awkward when you are taking their advice on other matters.

    I have read that those in old peoples’ homes who live the longest have the highest cholesterol levels and I shall be interested to follow up on the references given>

  10. RAMAN K GIRADKAR 18 July 2008 at 11:22 am #

    THE COMMENTS WHICH I READ IS REALY FANTASTIC AND VERY HEALPFULTO ME AND MY FAMILY.

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    [...] Dr John Briffa wrote a fantastic post today on “When it comes to cholesterol, is lower really better?”Here’s ONLY a quick extractVery few of us will not have noticed that the last couple of decades have seen a concerted effort from health agencies and health professionals to persuade us that we should be driving our cholesterol levels to lower and lower levels. … [...]

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