Chapter 1, Problem 52SE

Association between Glycemic Load and Acne? An article in the Journal of the Academy of Nutrition and Dietetics reported on a study of diet in subjects with moderate to severe acne. Read the excerpts from the abstract and answer the questions that follow. (Source: Burris et al., “Differences in dietary glycemic load and hormones in New York City adults with no or moderate/severe acne,” Journal of the Academy of Nutrition and Dietetics, vol. 117 [September 2017]: 1375-1383)

Methods: Sixty­four participants (no acne, $n=32$ ; moderate/severe acne, $n=32$ ) were included in this study. Participants completed a 5­day food record, had blood drawn and completed a questionnaire to evaluate food­aggravated acne beliefs and acne­specific quality of life.

Results: Participants with moderate/severe acne consumed greater total carbohydrate compared to participants without acne. Participants with moderate/severe acne had greater insulin compared to participants without acne. Although there were no differences between groups, 61% of participants reported food­influenced acne.

a. Was this a controlled experiment or an observational study? Explain how you know.

b. Assuming the study was properly conducted, can we conclude that higher consumption of carbohydrates causes more severe acne? Explain.