13.6.11

Harvard anti-low carb "study" pole-axed

A 2010 Harvard study with the title "Low-Carbohydrate Diets and All-Cause and Cause-Specific Mortality" purportedly found that:
Conclusion: A low-carbohydrate diet based on animal sources was associated with higher all-cause mortality in both men and women, whereas a vegetable-based low-carbohydrate diet was associated with lower all-cause and cardiovascular disease mortality rates.
one to ridicule the "junk science" in this article is Dr Chris Masterjohn: The Daily Lipid: New Study Shows that Lying About Your Hamburger Intake Prevents Disease and Death When You Eat a Low-Carb Diet High in Carbohydrates

here is another - largely in laymans language: Brand-Spankin’ New Study: Are Low-Carb Meat Eaters in Trouble? « Raw Food SOS: Troubleshooting on the Raw Food Diet . its by celebrated demolisher of the China Study Denise Minger, who concludes:

Bottom line: In this study, when you look closer at the data, differences in mortality appear to be unrelated to animal product consumption. Changes in cancer and cardiovascular risk ratios occur out of sync with changes in animal food intake.
So what is responsible for the Vegetable Group’s lower mortality hazard ratios (and the Animal Group’s higher ones)?
Here’s a clue. Every time the researchers made multivariate adjustments to the data to account for the risk factors they did document (including physical activity, BMI, alcohol consumption, hypertension, and smoking, among other things), the hazard ratio went down for the Animal Group (meaning it got better) and it went up for the Vegetable Group adherents (meaning it got worse). That indicates pretty clearly that the Animal Group adherents had more proclivity to disease right from the get go, regardless of meat consumption, and the Vegetable Group adherents may have been more health-aware than most folks. (To see what I’m talking about, look at the mortality tables under the “10″ column, and compare the “Age- and energy-adjusted HR” with the “Multivariate-adjusted HR” for each group.)
In other words, it looks like what this study really measured was a Standard American Diet group (aka highest Animal Group decile) and a slightly-less Standard American Diet group (aka highest Vegetable Group decile). Both ate sucky diets, but the latter had slightly less suckage. You can bet the farm that neither was anything close to “low carb.” And if you have two farms, you can bet the other one that neither diet group was anything near plant-based, so I’m not sure the vegan crowd has much to gloat about here.

The End.
the comments section of Minger's blog are consistently entertaining if not informative - here is a taste:

8 09 2010
Richard Tamesis, M.D.
Finding out that Harvard students and faculty aren’t really that much smarter than the rest of us was the first hard lesson I learned when I arrived to do a post-residency fellowship over there in 1988. And to think this study was funded by the NIH with taxpayer money. Reply
brian0918
How does this crap get through peer review? Not only do the conclusions not follow logically from the data, but they are complete misrepresentations of the data. How can you label these groups “Animal” and “Vegetable”, or the diet “Low Carb”, when none of those labels are accurate, given the most common understanding of an Animal Diet or Vegetable Diet or Low-Carb Diet.
Do they even try to justify their labeling? The labeling was clearly pre-crafted to produce the desired plain-language conclusion.
Reply
Masxon X Hamilton
Hey, don’t you read – this is from Haaaavaaaaad! Simply has to be beyond question. From a critical thought process standpoint this country is totally lost and there simply aren’t enough people like Denise to keep this kind of crap science out of circulation – Haaaavaaaaad or not.
9 09 2010
Jim Stone
Let’s be careful here. Willett does some good work (though I have some concerns about some of his work), and Hu (the primary on this one) has a lot of very good papers. This particular paper does seem to be an exercise in creative framing, though. For one thing, it’s a little confusing how we’re supposed to use the mortality tables when the baselines in the three rows are different. If these are deciles, aren’t there also supposed to be roughly equal numbers in each bin? (Maybe I should dive into the main text of the article to get more info on how they created their bins) For male CVD, the 373 deaths in the high veggie decile 1 bin, seems somewhat anomalous, and yet it’s the baseline for all those low veggie numbers in the rest of the veggie row. For animal, (male CVD again) bin 1 has an n value of 270, and bin 10 is 264. Yet the HR ratio is 1:1.42. The latter number is “age and energy” adjusted. So, either there were some major age adjustments (and for that we need to factor in background demographic trends), major energy adjustments, or the bins aren’t close to equal for some reason. Just a very confusing way to present the data, I think. Jim P.S. Overall, it looks like soluble fiber might be something good to hypothesize about based on this data.
10 09 2010
Richard Tamesis, M.D.
This paper was probably written by one of Dr. Hu’s fellows, given the fact that Dr. Hu is listed as the last author in the paper. They probably did it during their fellowship and he signed off on it when they submitted it for publication. He shares in the blame for any mistakes or poor analysis made in the paper, and so do the peer reviewers who didn’t seem to have as much sense and smarts as Denise.