In John Tierney’s blog, Gary Taubes is very critical of nutrition researchers:

The last place you want a science to find itself is where obesity research is today, with hypotheses of causation that can explain none of the pertinent observations, but yet are believed so fervently that no one can challenge them without being ostracized or declared a quack.

Fair enough. But Taubes (and Tierney) make the usual mistake of being too critical and not enough appreciative. I figured the real wisdom would be in the comments, and I was not disappointed. Taubes thought physics functioned better than nutrition. One comment:

It’s not that the scientists [in physics and nutrition] are any more or less skeptical, or that it takes any longer for the truth to emerge, it’s that the public is more likely to be paying attention [to nutrition] in the meantime. And human beings as a group are extremely bad at reasoning under uncertainty.

Quite right. If Taubes and Tierney have trouble seeing the big picture (although Good Calories Bad Calories is a big-picture book) surely most people, and other journalists, do much worse. Another comment:

People like the old “correlation does not equal causation” slogan, but it’s not correct to translate that as “correlations are completely uninformative,”

Well put. (I blogged about this.) My favorite comment, however, was not wise:

Tierney stresses the errors and biases of nutrition science – but what of its successes? [Good start.] . . . As Tierney surely knows, there is a solid body of research that cumulatively demonstrates the positive effects of a balanced diet, lots of fresh fruit and veggies, avoidance of saturated fats, moderate consumption of calories and regular exercise. This is common sense, and science backs it up.

The history of nutrition teaches the opposite. The most helpful findings have not been “common sense”. Folate supplementation greatly reduced birth defects. Not common sense. Eat oranges to cure scurvy: Not common sense. Pellagra due to nutrition rather than infection: Not common sense. The whole notion of vitamins: Not common sense (deficiency diseases were attributed to poisons). “Common sense” approaches to losing weight, such as “moderate calorie intake”: Failed miserably.

It’s true that traditional foodways often turn out to be very healthy, but they can’t be called “common sense” because they vary so much from one place to another.

Thanks to Dave Lull and Tim Beneke.

Very.

The single most striking result in the history of the cholesterol controversy . . . passed without comment by the authorities: those Framingham residents whose cholesterol declined over the first fourteen years of observation were more likely to die prematurely than those whose cholesterol remained the same or increased. They died of cardiovascular disease more frequently as well.

Around 1990, nineteen studies found that both women and men had higher total mortality at the lowest cholesterol levels (< 160). The increase came from more “cancer, respiratory and digestive diseases, and trauma.” From Gary Taubes’ fascinating new book Good Calories, Bad Calories.

I expect these results are corrected for income but I’m not sure. A friend of mine is very poor. “You have the cholesterol level of a Chinese peasant [i.e., very low],” his doctor once told him.

Interview with Taubes (October 9).

Another excellent post from Michael Eades discusses a new study that found elderly people with lower cholesterol had faster cognitive decline than those with higher cholesterol. Suggesting that cholesterol protects your brain.

There are several reasons to think this association reflects cause and effect. First, earlier studies found the same thing. Second, an earlier study found that people whose cholesterol was lowered had higher rates of violent death — an unexpected side effect that implies brain dysfunction. Third, as Eades points out, the brain contains lots of cholesterol.

Thanks to Tom.

John Tierney has an interesting column in the NY Times today about how many Americans — including the Surgeon General and the McGovern Commission — came to mistakenly believe that low-fat diets were better than diets with more fat.

Thanks to Dave Lull.

The Framingham Study is a famous long-term health survey. According to an NIH webpage, its goal was “to identify the common factors or characteristics that contribute to CVD by following its development over a long period of time in a large group of participants who had not yet developed overt symptoms of CVD or suffered a heart attack or stroke.”

That is not quite right. It was originally called the Framingham Diet Study. Now it is called the Framingham Heart Study. Why the change? Well, Michael Eades, the author of Protein Power, found an early report on the findings of this study and wrote a fascinating post about it. One of his excerpts from the report:

In undertaking the diet study at Framingham the primary interest was, of course, in the relation of diet to the development of coronary heart disease (CHD). It was felt, however, that any such relationship would be an indirect one, diet influencing serum cholesterol level and serum cholesterol level influencing the risk of CHD. However, no relationship could be discerned within the study cohort between food intake and serum cholesterol level.

In the period between the taking of the diet interviews and the end of the 16-year follow-up, 47 cases of de novo CHD developed in the Diet Study group. The means for all the diet variables measured were practically the same for these cases as for the original cohort at risk. There is, in short, no suggestion of any relation between diet and the subsequent development of CHD in the study group.

That is, the findings of the study completely contradicted what the researchers believed (as indicated in the name Framingham Diet Study). This is what Leonard Syme taught his introductory epidemiology students on topic after topic: Well-known conclusions are far less certain than you think.

Thanks to Tom.

This piece of a discussion at the Google Group sci.med.cardiology fascinated me:

[My] HDL was always around 32, until I dropped the low fat nonsense about 7 years ago. Adding healthy fats and dropping carbs brings my HDL to about 70 while boosting my LDL almost none. And after the HDL shot up, the low-carbing continued to produce weight loss without difficulty. I’ve never felt better in my life and I am 63 now.

I would like to raise my HDL. The advice I’ve read (do a long list of things) hasn’t helped. For example, one bit of advice was to lose weight. I did lose weight and my HDL briefly got much better. I kept the weight off but my HDL did not stay high. Whereas whatever this guy did had lasting effects. I tried to find out more about what he did but, alas, he didn’t answer my email.