Tuesday, July 14, 2009

From Junkfood Science

I suppose we all remember the big story about how rhesus monkeys kept on a highly-restrictive diet lived longer than those who were allowed to nosh at will. Turns out that this is only true if you, well, ignore the monkeys that died.

The lower mortality claimed among the monkeys on the calorie restricted diet were achieved only after eliminating 37% of the monkey deaths. They defined mortality as “age-associated deaths” and eliminated any cause of death they didn’t believe was associated with aging. As the supplemental data explains, 16 deaths from “non-age-associated causes were censored and their age of death used as the time variable in the regression.”

. . . The non-aging-related causes of death included monkeys who died while taking blood samples under anesthesia, from injuries or from infections, such as gastritis and endometriosis. These causes may not be aging-related as defined by the researchers, but they could realistically be adverse effects of prolonged calorie restrictions on the animals’ health, their immune system, ability to handle stress, physical agility, cognition or behavior.

As we know, the most important endpoint in medical interventions is all-cause mortality. Selectively looking at only one cause of death, while ignoring that more patients died from something else, is not evidence to support the efficacy of a treatment. “The treatment worked, but the patient died” is not good medicine that considers the whole patient."

More over on the Junkfood Science blog.

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5 Comments:

Blogger Sean Craven said...

The brain is essentially a big lump of think-grease. Lossa lossa cholesterol.

Need more be said?

10:25 PM  
Anonymous Technology Slice said...

Less digestion means a healthier life.

10:36 PM  
Blogger Marcus said...

i haven't read much on the subject - but here is a (somewhat pretentious) reference; somewhere in his works (i cannot remember where) nietzsche comments on a french philospher who recommends a very slim diet, something like an apple, rice and fresh water daily - i don't remember exactly what it was the french guy wanted everyone to eat (nor how little). anyway, nietzsche makes a point of shooting down lines of thought like that, where you make something that works for you an almost religious idea of how everybody should behave (much like the recent monkey-business). diets are inflamatory subjects - many seem to invest themselves rather heavily into an idea of health that, to them and therefore everybody else, must be the true path to a long life. nietzsche says that if he ate as a little bird, as the french philospher recomended, he would not survive, he needs lots of food to be able to function (and climb the alps). nietzsches point is that everyone has to find out what works for him or her, if, on the other hand, the french guy ate like nietzche he would certainly get ill. of all things that nietzsche says this, i think, is one of the healthier remarks.

2:43 AM  
Blogger Michael Grosberg said...

I find it difficult to parse the scientific jargon on the original document. I understand they eliminated 37% of deaths from their statistic, but how were these deaths divided between the control group and the test group? if they were more-or-less evenly eliminated from both groups the result (whatever it is) is still valid.

5:21 AM  
Blogger Ralf the Dog said...

How many of the fat monkeys died because the hungry monkeys ate them? I know that for my self, lack of food leads to aggression.

12:45 PM  

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