Cholesterol makes you smarter!

Ready for a doozy?

It turns out there’s research showing that for seniors, the lower your serum cholesterol, the higher the risk for cognitive decline.

Here’s an abstract of a Neurobiology of Aging research paper on the topic.

Here’s a translation of the study findings in lay language:

A group of researchers in the Netherlands did a study looking at cholesterol levels and cognitive decline and found that the elderly with the highest cholesterol levels were able to think better than their counterparts with low levels of cholesterol . . .

The researchers divided a group of 1181 elderly people (ave age 75) into groups of high cholesterol, medium cholesterol and low cholesterol levels. They administered reliable tests designed to determine general cognitive function, memory and information processing speed. Across the board subjects with the highest cholesterol levels performed the best, followed by those with medium cholesterol levels. The group with the lowest cholesterol levels performed the worst.

The scientists followed these groups of people for about six years and found that all groups followed about the same trajectory of mental decline, but the group with the highest cholesterol levels ended up with better function than the other two groups simply because they started from a better position at the beginning.

The research team also studied members of the group of subjects who were carriers of a certain genetic marker that is associated with greater rates of Alzheimer’s disease. The folks in this group that had the lowest cholesterol levels had a more precipitous decline in mental function over the six years than did those who had the same genetic marker but were in the high cholesterol group.

This is not the only study that has shown the cholesterol is protective against cognitive decline – it’s only the most recent.

Yes, but high cholesterol raises your risk for heart disease, right?

Actually, if you Google “cholesterol myth” you’ll be deluged by folks who argue otherwise.

At the very least, anyone who is either A.) a woman or B.) a man over 50 needs to ask some serious questions. See this, for instance–an article on Spiked Online by Malcolm Kendrick:

Perhaps the largest single analysis of cholesterol levels, and death from cardiovascular disease (and other diseases), was published in 1992. This review included over 100,000 women, aggregated from a number of different studies and countries.

To quote from the study: ‘The pooled estimated risk for total cardiovascular death in women showed no trend across TC (total cholesterol) levels.’ In short, for more than 50 percent of the world’s population – women – raised cholesterol is not a risk factor for heart disease.

Moving to men, it is true that under the age of 50 there does seem to be an association between raised cholesterol levels and heart disease. But after the age of 50, when more than 90 percent of heart attacks happen, the association disappears.

That’s not all. Not only is high cholesterol not associated with increased risk for heart disease — low cholesterol is linked with increased risk of . . . dying.

As Kendrick states: once you’ve crossed 50, “the lower your cholesterol level is, the lower your life expectancy.”

His assertion is supported by the two major studies regularly cited as supporting the notion that high serum cholesterol is dangerous — one conducted in Honolulu, one in Framingham, Mass. Kenrick writes:

. . . a falling cholesterol level sharply increases the risk of dying of anything, including heart disease.

The dangers of a low cholesterol level were highlighted by a major long-term study of men living in Honolulu: ‘Our data accord with previous findings of increased mortality in elderly people with low serum cholesterol, and show that long-term persistence of low cholesterol concentration actually increases the risk of death.’

Somewhat ironically, the danger of a falling cholesterol level was first discovered in the Framingham study: ‘There is a direct association between falling cholesterol levels over the first 14 years [of the study] and mortality over the following 18 years.’

It seems almost unbelievable that warnings about the dangers of a high cholesterol level rain down every day, when the reality is that a low cholesterol level is much more dangerous than a high level. Given this, why would anyone want to lower the cholesterol level? On the face of it, it would make more sense to take cholesterol-raising drugs. Especially after the age of 50.

Add to that the fact that statins — cholesterol-lowering drugs, Lipitor being one well-known brand — subject people to the risk of serious side effects.

So what’s going on?

Some people think it’s a vast pharmaceutical company conspiracy. After all, statins are a multi-billion dollar business.

A less malevolent but equally plausible explanation is that we’re in the grip of the cascade effect, as described in this NY Times article linked by Instapundit the other day:

We like to think that people improve their judgment by putting their minds together, and sometimes they do. The studio audience at “Who Wants to Be a Millionaire” usually votes for the right answer. But suppose, instead of the audience members voting silently in unison, they voted out loud one after another. And suppose the first person gets it wrong.

If the second person isn’t sure of the answer, he’s liable to go along with the first person’s guess. By then, even if the third person suspects another answer is right, she’s more liable to go along just because she assumes the first two together know more than she does. Thus begins an “informational cascade” as one person after another assumes that the rest can’t all be wrong.

Because of this effect, groups are surprisingly prone to reach mistaken conclusions even when most of the people started out knowing better, according to the economists Sushil Bikhchandani, David Hirshleifer and Ivo Welch. If, say, 60 percent of a group’s members have been given information pointing them to the right answer (while the rest have information pointing to the wrong answer), there is still about a one-in-three chance that the group will cascade to a mistaken consensus.

The NY Times piece focuses on the belief — increasingly discredited — that low fat diets are good for you. But it seems to me you could argue much the same about serum cholesterol levels.

It isn’t easy to go against the advice of our doctors. I know of one senior who refuses to take statins. He’s harangued every time he goes to the doctor.

It isn’t easy to go against consensus opinion. But hey. It’s character-building!

Me, I’m planning for my cholesterol levels to be off the scale ;-)

[tags] cholesterol [/tags]

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6 Responses to Cholesterol makes you smarter!

  1. Deb says:

    Good analysis, Kirsten. Interesting. There was no way I was giving up whole eggs anyway!

  2. Kirsten says:

    Another piece of the whole cholesterol thing is that diet has very little effect on serum cholesterol levels.

    I didn’t get into that since this post got long enough without it :-)

    Another interesting tidbit is that Vitamin D levels may be a key to heart health. It’s not been proven yet but apparently there’s a strong correlation between living at lower latitudes and low incidence of heart disease.

    This page isn’t very esthetically pleasing but it does include a lot of links to research studies to make that case:

  3. …and do you think that the “cascade effect” might also account for the incessant hype and hysteria about “man-made global warming” you wrote about in the previous post? Who was it that said if someone says something often enough, it is assumed to be true?


  4. Kirsten says:

    Very well could be, John.

    The NYT article singled out medical research as particularly prone to it but I should think scientific ideas are just as vulnerable.

    In fact we can probably assume that a good third of all “accepted” scientific and medical beliefs are wrong, based on this model ;-)

  5. jan says:

    For years I ate oat bran because it was supposed to have some health benefit even though it tasted like cellophane. Then suddenly…oops, we were wrong. It isn’t healthy after all. That was many years ago. Now I’ll just wait for what I like to eat to get back on the “good” list.

  6. Kirsten says:

    Oh, I didn’t realize oat bran got dropped!


    It’s damn near impossible to keep track, isn’t it.

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