Kurt Harris MD

An Archevore is someone who eats based on essential principles, and also someone who hungers for essential principles. Take your pick.

Exploring these principles is one of my interests, but not the only one.

So you may find commentary here about other issues in medicine, health, other sciences, or just about anything.

Feed The Archevore

Archevore is written, produced, and directed by me. I am an independent science writer with no outside sponsorship from any private firm, NGO or, Zeus forbid, government agency. Donations are greatly appreciated. 


In addition to buying from the book list, you can also support Archevore by making all of your Amazon purchases for any item through the Amazon Portal below.

Amazon Portal

 

 

Buy gold online - quickly, safely and at low prices

 

« More N = 1 | Main | New Jimmy Moore Interview »
Thursday
Jan272011

N = 1?

In common usage in the medical world, the phrase "n=1" is often used in the pejorative. A colleague tells you of some clinical scenario, perhaps involving some patient and their favorable response to medical intervention. You doubt the universality of the observation, so you might say "Yeah, but that's just n=1". You are trying to say that it is anecdotal. That we should be more scientific in our thinking. That n=1 is obviously not enough. It is the opposite of a large, randomized well-controlled trial.

In the "paleo" and health blogosphere, I see "N=1" experimentation, used unironically as a guiding principle, almost a fetish.

It is often explicitly stated that "how it works for you" and especially "how you feel" is the ultimate arbiter of the advisability of dietary maneuvers.

Ultimately, in the literal sense, as the LAST thing to be considered, this is true.

But the starting point should always be the soundest science - based evidence and reasoning.*

Many practicing physicians will instantly understand my skepticism, as will students of human consciousness and anyone who appreciates the radical subjectivity of human experience.

I had a patient once who claimed she was allergic to every food except skinless chicken breast and oatmeal. She ate nothing else for years.

I have had patients with back pain claim that their backs were ruined by the most trivial of events, such as lifting a 10 lb UPS package 5 years previously.

One lady claimed a large swelling on her leg occurred at a result of tripping over her cat. It turned out to be a malignant tumor.

I had a male patient present with a golfball-sized tumor his testicle, and when I told he and his young wife that it was a tumor, they both swore it had only appeared a few days ago. She was actually incensed at me, insisting that she was frequently and intimately familiar with her husbands anatomy, as there is NO WAY she would not have noticed such a thing…

One of the things I am concerned about in encouraging people to closely monitor their responses to food is creating an army of people with real but essentially psychosomatic (created by the brain) reactions to possibly harmless foods, at the same time as we are reassurring them that if they “feel fine” eating something, then that means it is harmless.

I felt absolutely fine drinking up 4 coke classics a day in my youth, no lie. I was in good shape and not obese.

Conversely, a person with undiagnosed celiac disease may have no symptoms whatsoever until they have type I diabetes, Hashomoto’s thyroiditis or neuropathy or cancer.

Might the fact that you feel so much better without something in your diet be because because of your expectations?

Both the placebo effect and its opposite, the nocebo effect are very powerful. Often more powerful than actual drugs in clinical trials where the effects can be assessed.

Why should we doubt that we can fool ourselves about just about anything?

Don't some people think they feel great on whole grains and soy and maybe even vegan fare, attributing even negative symptoms to "detox" or "candida die off" or other nonsense?

Just to be nice and sparkling clear, I am not saying one should not pay attention to how you feel with dietary changes. Far from it.

I am really just taking issue with two things:

1) Using the subjective experience as “proof” that a salutary change was made. This is especially difficult when you are changing a huge number of dietary variables at the same time and, often altering the physical culture the person experiences in big ways. Arguing that if x feels better without y is highly unreliable. In the case of both wheat and “dairy”, we should make our arguments based on plausible science first, as the “feeling” may be absent or misleading and hard to separate from the other variables in either case.

2) The contradiction between telling people to “suck it up” if they are suffering without their wheat or sugar or starches or milk, at that same time that they are being told to closely monitor how they feel as a gauge to what to eat.

It will be best to always emphasize N=1 objective measures of health like blood pressure, waist size, glucoregulation, etc.

Ultimate means last. Use N=1 subjective experience as the ultimate - last - test in this literal sense.

If you apply N=1 subjective evaluation to dietary maneuvers that were not totally grounded on science in the first place, you are liable to seriously fool yourself.

*This is really the only thing differentiating sound from unsound. The intitial science behind the dietary principle is the only differentiator. Just read 30 Bananas a Day or any vegan website to see what I mean. The subjective experience in the short term cannot be the crux. Humans can eat anything in the short term.

PrintView Printer Friendly Version

EmailEmail Article to Friend

Reader Comments (6)

Well said as usual. Along these lines, advice I got from a more-clueful-than-most doc a few years ago that might be worth amplifying with your point (1): Change only one thing at a time and wait at least a month before changing anything else, so as to be able to (more) fairly judge the effects. Obviously this isn't the best approach in all circumstances, but when looking for the source of a specific issue, it's a useful rule.

January 27, 2011 | Registered CommenterJohn Rosevear

Thanks Dr. Harris for pointing out what we should already know especially in the light of our individual past histories. One does not always/usually "feel" the damage being done, otherwise one would have stopped doing the damage in the first place. (self-destructive tendencies the exception)
The alternate to John Rosevear's plan is to change everything and then reintroduce over time. Or my personal favorite, start feeling crappy or have some digestive distress then try to figure out what you did different to cause it. Not a controlled scenario but one I tend to fall into. When you have a reaction of sorts without any expectation of a reaction it does minimize the placebo effect, at least in my n=1, anecdotal experiences.
TPSW - dv

January 27, 2011 | Registered CommenterDianne V

the converse problem occurs when even true observations about an individual are generalized for the whole population. and my difficulty with the gold-standard - randomized placebo-controlled studies - is that they can identify phenomena which are statistically true for a population, but not necessarily true for me or the individual i'm dealing with. nonetheless, those observations are the place to start.

January 27, 2011 | Registered CommenterJeff Klugman

In my work I deal with placebo and nocebo effects constantly. In general they tend to extinguish after a few months, which is one way to tell the difference between placebo/nocebo and a "real" effect of a modification.

January 27, 2011 | Registered CommenterEmily Deans MD

Induction is a bitch, but can be very useful if handled with extreme care and skepticism.

January 27, 2011 | Registered CommenterAaron B

Thanks for yet another thought-provoking article. I appreciated the cordial-ish exchange on Robb's site, and (unlike some other commenters there) I'm completely good with simple disagreement. Shoot, why does everyone need to be "right"? I have a modest body of experience and education, and both of those are constantly growing. And, like other folks that you've posted about, my position on some things sometimes shifts over time as my understanding and experience changes me. On other things, my current position stays firmly where it has been for years. Anyway, on to my actual point.

I think that there should be a marriage of peer-reviewed science and personal/collective experience. That partnership allows for real-time improvements, instead of waiting for the consensus of published, peer-reviewed research to indict or acquit one particular food or food group. The solo act of a science-only approach, while it avoids the (valid) placebo concern, spawns extended periods of time (decades!) with no definitive answer for the masses that are so, so sick these days. I agree with you on the general reduction (or complete omission) of wheat/gluten, fructose, and LA, but I'm not clear on how both you and I concluded that these things are less-than-awesome, since scientific research is far from "complete and conclusive" on even these topics. So while there are some publications that suggest that most folks would do better without these, we've "married" that incomplete scientific evidence with experience, and forged our opinion, right? I think the general dismissal of individual experience as a valuable indicator leaves the general public open to more "science-based" recommendations like the Food Pyramid, etc. Of course, the money and politics of that is another discussion. I guess I feel like the complete reliance on published literature to support one's position is unhelpful for folks desperately trying to sort through all the conflicting recommendations. Robb's "try it and see" approach was, I suspect, a response to the constant rebuttal of some scientific suggestions (if not conclusions) that he drew from his education and research. I don't think it's at all detrimental to perform a case study of yourself by removing foods, reintroducing them, and evaluating how you do. However, I do think that waiting til all possible doubt has been removed by scientific study could have some tangible consequences. I, personally, would rather err on the prudent side, even if that's construed as a precursor to paranoia. Thanks for the dialogue.

January 27, 2011 | Registered CommenterDallas H
Comments for this entry have been disabled. Additional comments may not be added to this entry at this time.