Little white lies in stroke research?

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Does the proverbial apple a day really prevent stroke, as a Dutch study now in the journal Stroke suggests? Or is it just that the kind of people who eat more fruits and vegetables are more likely to lead healthier lifestyles in general? Who knows? But the 10-year study of over 20,000 adults found that the risk of stroke was 52 percent lower for those participants who consumed the greatest amounts of so-called white fruits and vegetables a category that includes apples, as well as pears, bananas, chicory, and cucumbers

For the purposes of their study, the researchers categorized fruits and vegetables according to the color of their flesh, which indicates the type of nutrients it contains. In addition to white, the other color categories were green, orange and yellow, and red and purple. At the beginning of the study, which required participants to answer a 178-item food questionnaire, none of the participants had cardiovascular disease. Over the course of the next 10 years, 233 had suffered strokes. It turns out that those who regularly consumed more of the white-fleshed fruit and veggies were significantly less likely to have had a stroke; researchers calculated that, for every 25 grams consumed daily from the white color category, the risk of stroke dropped by 9 percent. Eating lots from the other three categories showed little effect, however.

Data dredging, says ACSH's Dr. Gilbert Ross, referring to the unseemly practice of mining data for superficially related factors. He notes that, ultimately, the researchers were comparing the 233 people who suffered strokes with the over 19,700 who didn t not a terribly balanced set of subjects.

As ACSH s Dr. Ruth Kava notes, The most important part of the study is the authors acknowledgement that they couldn t rule out the possibility that the reduced risk of stroke might be related to the fact that those who eat more fruits and vegetables might have healthier lifestyles overall.

ACSH s Dr. Josh Bloom agrees. It is impossible to conclude anything from this study, he says. There are just too many variables.