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Biased But Necessary: Single Case Studies

The views expressed are those of the author and are not necessarily those of Scientific American.


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Like a kid who skips the copyright information that precede iPad games, I go straight to the clinical cases in the New England Journal of Medicine whenever I get my hands on a copy. Recently I browsed through a bunch of cases in the online archives. In 1823, the journal called these vignettes “hospital reports.” Some could have been penned by Dickens himself. In one particular case, a 70-year-old man from the coastal city of Duxbury walked into Massachusetts General Hospital with a “dreadfully painful complaint in the face.”  A certain Dr. Warren listened carefully to the patient’s symptoms. These are duly recorded in the hospital report. If I had the means to subscribe to NEJM, I would know how the story ends (the rest is behind a paywall).

Case studies may be biased toward a single individual or a small group of people. However, until more evidence can be built up, they are necessary for tracking mysterious and established disease conditions that suddenly appear on scene. At the beginning of October, I didn’t have any particular condition in mind when I started my highly arbitrary “clean eating” diet. The experiment was a great excuse to think about food. It was also a study in personal health. Whether I had primed myself to think I felt healthier or not, I did notice feeling better after certain meals. I thought about the ingredients of everything I ate. I wondered which countries the ingredients came from. Not for my vegetables, though. I’d met the farmers who grew my tomatoes, Swiss chard, green okra and fingerling potatoes.

Fingerling potatoes roasted in olive oil with feta cheese. A bowl of raspberries, bananas, walnuts and yogurt. Sparkling water.

My notes stay pretty detailed until about halfway through the month and then my records get spotty. The clean eating method I chose (no meat, no alcohol, no fish, no canned foods, no processed food) was arbitrary. Several readers accurately pointed this out. Others gave me links to websites that discuss clean eating. But I could still find no evidence of this particular diet covered in my trusty source on medicine and health studies: PubMed. And in his intricately researched book, The Cancer Chronicles, veteran science writer George Johnson notes lacking conclusive evidence between diets and cancer.

While I hear my mother’s voice urging me to slice up carrots and eat an apple with my lunch, my Dutch in-laws eat sandwiches with cheese or chocolate sprinkles and seem none the worse for it.

Baked Swiss chard with pistachio nuts. Almond butter w/ honey on Ezekiel bread.

Back to the study. It was supposed to last four weeks, but I have complete data for only two. I intended to not eat bread at all, but somehow Ezekiel bread sprouted into my breakfast every morning. Other notes (or duh’s!) from the self-experiment include:

- On days that I ate very little bread and mostly fruits and vegetables I also tended to exercise for longer periods of time;

- My energy levels seemed to increase by the end of the second week on the diet, but I have no measures whatsoever to support this feeling;

- Since I was paying such close attention to what I ate, I also ate less than what usually do (and studies support this).

Microsprouts, cherry tomatoes, yellow bell peppers wrapped in a whole wheat tortilla

When I interview researchers and scientists on new findings or papers, I love to ask this: What surprised you most about this study? In my case of “clean eating,” I was shocked to discover that I had enough willpower to stop eating mint chocolate chip gelato (which fell under the processed food category). The clean eating regime turned into a game for me and I wanted to beat it. Recently, I’ve gone back to eating the gelato again. I must say: I don’t feel so well after eating it.

There were other insights, too. I was able to quickly make decisions when dining out. With a few exceptions, I had to order the salad, no dressing. And that old truism reared its ugly head: You crave what you can’t have. I rarely eat red meat and never poultry. (Years ago, after I’d gently tried to coax a morbidly overweight chicken, fallen from a trailer truck, away from a busy road, I vowed never to eat chicken again.) Strangely, though, during two weeks of strict dieting, I craved a juicy burger. So I gave into that one — it was the best lamb burger I’ve had.

What are some conclusions? All diets will always conflict with some evidence in the medical literature. We continue to gain fascinating insights into how food interacts with human biochemistry, immunology and the microbiome.  But we are humans, evolved to eat a lot, drink beer, toast cocktails, make mistakes and mess around with garlic and olive oil. My suggestion is: go try a case study of your own.

 

Kathleen Raven About the Author: Kathleen Raven is a writer living in Atlanta, Georgia. She received her MS in Ecology with a focus on sustainable agriculture and MA in Health & Medical Journalism from the University of Georgia. Follow on Twitter @sci2mrow.

The views expressed are those of the author and are not necessarily those of Scientific American.






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  1. 1. DanielWWalton 2:45 pm 10/31/2013

    I absolutely agree. The quirks of case studies, the exceptions, are what show science the problems in its rules.

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