“Evidence-Based Nutrition” Randomized controlled trials are considered
the gold standard of scientific evidence. Half get the active treatment,
half get a sugar pill— works great for evaluating new drugs, but
a concern is that evidence-based medicine has made a leap from considering
randomized controlled trials to be a high standard
to being the only standard. Consider this review of dietary
interventions for multiple sclerosis by the esteemed
Cochrane Collaboration. They basically concluded that
there’s not much diet can do. But what about Dr. Swank’s success in
treating MS with a low saturated fat diet, the most effective treatment
ever reported, published in some of the world’s
most prestigious journals? Of course, they knew about his work,
but the study didn’t fit the inclusion criteria considered for the review,
because it was not a controlled trial. Demanding randomized trials
makes sense for drugs. Look, they’re expensive;
they’re risky, killing off more than a 100,000
Americans every year. But a healthy diet has no downsides,
just good side effects, so we shouldn’t have to wait on randomized controlled
trials to start saving peoples lives. Consider smoking. It took more than
7,000 studies and the deaths of countless habitual smokers
before a consensus was reached in the medical community regarding
the causal link between smoking and lung cancer, and still without a
single randomized controlled trial. One has to wonder how many people
are currently suffering needlessly while they wait for a
randomized controlled trial to confirm the results found by
other kinds of strong studies? In fact, a famous statistician, Ronald Fisher,
railed against what he called propaganda to convince the public that
cigarette smoking was dangerous. Since they cannot produce evidence
from randomized controlled trials, like a 1,000 kids banned
from smoking; you put another 1,000 kids forced to
smoke at least a pack and a half a day. Now if you did that kind of experiment,
then there would be no difficulty. Maybe instead of smoking causing lung
cancer, lung cancer causes smoking. In its earliest stages lung cancer
may cause inflammation, and so anyone suffering
from chronic inflammation is going to want to smoke a cigarette
to make themselves feel better and it’s kind of comfort
that might be a real solace to anyone in the 15 years
of approaching lung cancer. And to take the poor chap’s
cigarettes away from him will be rather like taking a
white stick from a blind man. It would make an already unhappy person
a little more unhappy than he need be. Fisher made invaluable contributions
to the field of statistics, but his analysis of lung cancer
and smoking was flawed by an unwillingness to examine
the entire body of data available. His smokescreen may have been
because he was a paid consultant to the tobacco industry, but also
because he was himself a smoker. Part of his resistance
to seeing the association may have been rooted in his
own fondness for smoking, which makes me wonder
about the some of the foods many nutrition researchers
may be fond of as well. A famous paper in the British Medical
Journal lampooned this insistence on randomized controlled trials
as the only legitimate evidence. “Parachute use to prevent death and major
trauma related to gravitational challenge: a systematic review of
randomized controlled trials.” Ah, they didn’t find any. Sure parachutes appear to reduce the
risk of injury after “gravitational challenge.” We can observe that people
who fall out of planes without them do tend die a bit more
than those with parachutes, but their effectiveness has not been
proved with randomized controlled trials. Advocates of evidence-based medicine
have criticized the adoption of interventions evaluated by
using only observational data. We think that everyone might benefit
if the most radical protagonists of this evidence-based medicine
organized and participated in a double blind, randomized, placebo-
controlled trial of the parachute. In other words, individuals who insist
that all interventions need to be validated by a randomized controlled trial data
need to come down to earth with a bump.