Month: November 2007

The Wisdom of Crowds (Babylonian edition)

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Herodotus on Babylon:

They have no physicians, but when a man is ill, they lay him in the public square, and the passers-by come up to him, and if they have ever had his disease themselves or have known any one who has suffered from it, they give him advice, recommending him to do whatever they found good in their own case, or in the case known to them; and no one is allowed to pass the sick man in silence without asking him what his ailment is.

Suroweicki’s book, like this example, was actually about the wisdom of passers-by (unconnected individuals) rather than crowds.

Thanks to David Cramer.

What Causes Heart Disease? Malcolm Kendrick’s Views

Seth Roberts6 Comments

In this video Malcolm Kendrick, a Scottish doctor, points out the lack of cross-country correlation between cholesterol levels and heart disease rates.

In this video Kendrick explains why he believes that extreme stress — often caused by emigration — is a big reason for high rates of heart disease.

This view is supported by research by Michael Marmot and others on the social gradient: People higher in occupational level have better health than those below them. This seems to be because lower jobs are more stressful. The lower your job, the less control you have. Lack of control is the problem.

Kendrick’s view calls into question the usual interpretation of migrant studies. When persons emigrate across countries — from Japan to America, from India to England — they usually have higher heart disease rates in the new country This is often attributed to differences in diet — the old-country diet is presumed healthier than the new-country diet. Kendrick lays the blame elsewhere. He also makes an interesting point about Finland. Finland used to have a very high rate of heart disease. Kendrick points out that in the early 1950s, about 700,000 persons of Finnish descent were pushed by the Soviet government out of the Soviet Union and into Finland. Kendrick also mentions Roseto, Pennsylvania, a town created by emigration en masse from Roseto Italy. The old customs and social networks survived the move intact and the people of Roseto Pennsylvania were. for many years, remarkably healthy.

Previous posts on heart disease: Omega-3 and heart attacks (also here). The Framingham Study.

Thanks to Dave Lull.

Addendum: Kendrick on “ The Great Cholesterol Myth.”

Mitch Kapor on Second Life

Seth Roberts5 Comments

Yesterday I heard Mitch “Lotus 1-2-3″ Kapor give the third of three talks at the UC Berkeley I-School on “ Disruptive Innovations I have Known and Loved” (podcast). This talk was about Second Life; the first two were about the PC and the Internet. It was a very nice talk I would have enjoyed more if I hadn’t had a cold. Even with a cold I was pleased by two things:

1. A graph of on-line Second Life activity. It was increasing at roughly the same rate as SLD-forums activity.

2. A comment that the short-term effect of similar technologies is less than expected; the long-term effect is far greater than expected. One long-term effect Kapor predicted is virtual meetings. I knew someone who was head of design for a very large powerful company — supposedly a dream job. But he had to travel all over the world to meet with his subordinates. Incredibly exhausting. So it wasn’t a dream job, and he gave it up.

I knew about the “disruptive technologies” idea from my work on variation in rat bar-pressing, which led me to read Clayton Christensen’s excellent The Innovator’s Dilemma. Disruptive technologies can be as simple as hydraulic power, which caused several steam-shovel companies to fold.

I had not thought of SLD as a technology; but I realized that’s what it is: A weight-loss technology. Disruptive, who knows, although Aaron Swartz was optimistic quite early. And today in the SLD forums I read this:

I’ve lost 85 lbs. and I have 25 lbs. to go and I just. Can’t. Quite. Process that idea. . . I’m at a new job where no one knows that I used to be incredibly heavy and there’s even a really cute fellow faculty member who seems to like me. He smiles at me. A lot. It’s nice. Everything is so . . . fantastic. I’m so happy I’m practically beside myself. . . . Almost every morning . . . I catch sight of myself in the full-length mirror out of the corner of my eye and the first thought is still “Is that me?”. And I have to stop. And look. And wrap my arms around my tummy – my much, much smaller tummy – and think “Oh that’s right. That IS me.” It always makes me laugh.

Podcasts of his earlier talks here (PC) and here (Internet).

My Theory of Human Evolution (osechi)

Seth RobertsLeave a comment

Sure, you know that in Japan, New Year’s is the big winter holiday. But did you know that osechi, a kind of fancy bento box, is a holiday tradition? Here are some examples:

osechi example 1

osechi example 2

osechi example 3

The cost, even to an American living in the Bay Area, is . . . surprising:

Just about every major department store and supermarket in Japan now stocks osechi ryori cuisine in December. Most stores offer osechi either as individual dishes or as sets, and many pass out elaborate catalogs to make the selection as easy as pulling out your wallet, which better be stuffed if you plan on ordering osechi as a set. . . . Price is determined by contents and the reputation of the wholesaler or restaurant which put it together. For example, a relatively unknown shop may whip up three 20 square centimeter boxes for ¥22,000 [= $200], whereas Kicho, a famous restaurant in Kyoto offers three circles of the same size for a hefty ¥196,000 [= $1800]. The rest of the sets, ranging anywhere from one to four tiers cost between ¥30,000 to ¥50,000 on average and most Isetan customers buy their ready-made osechi in this price range.

Osechi is another example of how holidays create a market for expensive difficult-to-make things. The Stone-Age predecessors of holidays helped support skilled artists, artisans, and craftsmen, the technological pioneers of the time.

Addendum: Bento boxes inspired the design of the IBM Thinkpad.

How Dangerous is Bariatric Surgery?

Seth Roberts3 Comments

From the abstract of a new paper on the question:

The 1-year case fatality rate was approximately 1% and nearly 6% at 5 years. . . .There was a substantial excess of deaths owing to suicide and coronary heart disease.

Six percent chance of dying within 5 years . . . Your chance of survival is probably better if you are posted to Iraq. On the other hand, another study found a 6% death rate within 5 years for matched obese persons who didn’t have the operation.

The Decline of Fact Checking at The New Yorker

Seth Roberts1 Comment

In the latest New Yorker, an article by Bill Buford begins:

Meat-eaters . . . have more recently had to accept that their diet is probably the source of much of the world’s . . . obesity.

Gary Taubes’ new book Good Calories, Bad Calories argues the opposite. Even if the fact checkers hadn’t read Taubes, surely they knew of the Atkins diet?

Addendum: Buford also blames heart disease on meat. In this talk Malcolm Kendrick notes an inverse correlation between saturated fat consumption and heart disease. Thanks to Dave Lull.

Interview with a Discoverer of the Importance of Omega-3

Seth Roberts2 Comments

Dr. Jorn Dyerberg was one of two Danish doctors who discovered that Eskimos in Greenland, with low rates of heart disease, have much more omega-3 in their blood than Danes in Greenland, with normal rates of heart disease. This was the beginning of the great interest in omega-3s. Here is an interview with Dr. Dyberg. Among his comments:

As for ALA, an omega-3 from plants that is converted in the body to EPA and subsequently DHA, he was unconvinced. In terms of biological effects of DHA and EPA, Dr. Dyerberg said there are many. “We don’t know of any specific biological effects of ALA,” he said.

“Tissue experiments give you an ALA concentration of zero. This omega-3 is either burnt or converted,” he said. “And the conversion is low.”

“If we want the benefits of omega-3, we have to eat them as long chain,” he said, referring to EPA and DHA.

My research — revealing very clear benefits of flaxseed oil, no doubt because of its ALA — shows this is quite wrong.

Thanks to Dave Lull.

Omega-3 and Blood Pressure

Seth Roberts4 Comments

I was surprised to see a chapter in Fish, Omega-3 and Human Health devoted to hypertension. Isn’t high blood pressure caused by too much salt and too much weight? Well, yes, but a special strain of rats used as an animal model of hypertension turned out to have a defect in their immune system. Perhaps high blood pressure is also caused by immune-system over-reaction.

A 1993 meta-analysis of studies of the effect of fish oil on blood pressure concluded:

Diet supplementation with a relatively high dose of omega-3 PUFA, generally more than 3 g/d, can lead to clinically relevant BP reductions in individuals with untreated hypertension.

The sizes of the blood pressure changes:

Weighted, pooled estimates of SBP [systolic blood pressure] and DBP [diastolic blood pressure] change (mm Hg) with 95% confidence intervals were -1.0 (-2.0 to 0.0) and -0.5 (-1.2 to +0.2) in the trials of normotensives, and -5.5 (-8.1 to -2.9) and -3.5 (-5.0 to -2.1) in the trials of untreated hypertensives.

A different meta-analysis reached essentially the same conclusion.

Note the use of fish oil. Fish oil has long-chain omega-3 fats, while flaxseed oil — which I have used in my self-experimentation — has only the short-chain omega-3 fat, which is converted to long-chain omega-3 after you eat it. Fish oil is often considered better because the omega-3s don’t need to be converted. But this way of thinking misses something. Because the omega-3s in flaxseed oil are converted to long-chain omega-3s by enzymes, the amount of long-chain omega-3 in the body rises more slowly (and thus lasts longer) than if you take fish oil supplying the same amount of long-chain omega-3. Flaxseed oil supplies a kind of time-release long-chain omega-3. A long low dose could easily be more potent than a short high dose.

Thanks to Dave Lull.

Israel Ramirez on Gary Taubes

Seth Roberts7 Comments

The theory behind the Shangri-La Diet was inspired by research of Israel Ramirez, which I describe in an appendix (”The Science Behind the Theory Behind the Diet”) to the book. I recently asked Ramirez what he thought of Gary Taubes’ idea in Good Calories, Bad Calories that we are fat because carbohydrate consumption pushes our insulin levels too high. He is especially well-qualified to judge because he has done experiments in which insulin injections induced obesity in rats. His reply:

As I understand Gary Taubes, he has resurrected Atkins’ idea that carbohydrates stimulate insulin which lowers blood glucose and thereby induces more eating. The evidence for this is not very compelling. You can induce overeating with insulin in lab rats but you have to give so much insulin that the animal is in danger of dying. I am not aware of any experiments of this sort in people but diabetics don’t often report being hungry after accidentally giving themselves too much insulin. There are exceptions to this pattern; for people and lab rats, glucose levels tend to fall shortly before eating.

There are clinical trials in people and lab rats showing that high protein, low carbohydrate, diets suppress intake. For people, the effects are modest in the long term, amounting to a few pounds greater loss than for people given a low fat diet at the end of a one year trial. There is some evidence that this weight loss might not be maintained after the first year. Trials showing weight loss on low carbohydrate diets required eating less carbohydrate than that consumed by 99% of lean people.

Cross national and historic data don’t strongly support Taubes. People in countries where traditional high carbohydrate diets are still consumed are often lean, i.e. Japan and China. In recent times, as people in these countries have shifted away from traditional starch diets, frequency of obesity has increased. Intake of soft drinks, on the other hand, does roughly parallel incidence of obesity. I interpret the beverage correlation as a psychological phenomenon but it is also consistent with Taubes.

Even if Taubes were entirely correct about carbohydrates, it would not contradict the idea that learning influences the amount of food you eat. Nor would it mean that extremely low carbohydrate diets are best or easiest way to lose weight; Seth Roberts’ method may still be easier for many people.