The Big Fried-Potato Question
During the eight-year study, only 236 of the 4,400 subjects died; fewer than 30 per year. We don’t know what caused their deaths; one would expect it to be heart attacks and strokes but that data was not examined. The researchers adjusted the analysis for a number of variables including age, but it would have been more valuable to know whether fried-potato consumption was related to early mortality. That would give us more of an indication that there really was an increased mortality from eating french fries three days a week.
The Big Question
The big question is simply this: why are researchers from Italy examining the relationship between potato intake and mortality in a study about osteoarthritis? On the surface, it doesn’t make any sense. There was no overall strategy outlined in the reasoning for the study.
One reason they did it is because it’s open-access data: anyone can examine the data and use it for any type of analysis. All I had to do was register and I could download all the data related to any of their questionnaires including the FFQ. I’m not going to analyze the data, but I could.
The study was designed to examine osteoarthritis (OA) and the variables that are important to its prevention and treatment: “The purpose of this study is to examine people who have knee OA or are at high risk for knee OA; information will be used to better understand how to prevent and treat knee OA.” No mention of looking at potato intake and mortality.
The problem is that the authors of the study did not design the variables to examine; they had to use what was already in the study. The questions might have been different if they begin with a study to examine their research question: does potato intake affect mortality in North America? Here’s an example. The authors did not include data from potato chips in their analysis. To be fair, they couldn’t because all snacks were lumped together: potato chips, corn chips, pretzels, and other snack food. If you were starting from scratch, you would definitely include separate questions on the types of snack foods. But this is the type of problem that occurs when you don’t design the study; you take whatever is there, and maybe it works and maybe it doesn’t.
The Bottom Line
What can we gain from this research paper? Not much—it’s mostly meaningless in the real world. But we can do this: be realistic in how we prepare foods and what fast foods we choose to eat. Deep-fried foods can be a part of your diet; just make them a small, infrequent part of it. Every food can be a part of your diet as long as you control the amount and how often you eat it. Eat less. Eat better. Move more.
What are you prepared to do today?
Dr. Chet
Reference: Am J Clin Nutr doi: 10.3945/ajcn.117.154872
