Teens may be chugging protein shakes and taking other muscle-enhancing supplements more often than previously thought, a new study found.
According to a self-reported survey conducted among adolescent males and females, nearly 35 percent said they used protein powders and shakes, while almost 6 percent reported using steroids, according to study author Maria Eisenberg of the University of Minnesota in Minneapolis, and colleagues. Both both behaviors were more common among boys versus girls.
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In comparison, recent studies with population-based samples of U.S. youth have indicated that 8 percent of females and 10.2 percent of males reported the use of protein supplements.
Use of muscle-enhancing products or behaviors to bulk up, such as different eating habits or exercising more, were significantly associated with grade level, Asian race, body mass index, and sports team participation, the current authors wrote in Pediatrics online.
Women and how media images impact thinness and body image has been the subject of a great deal of research, but images of men depicted in the popular media show people who are increasingly large, lean, and muscular, the authors pointed out.
"Boys' body dissatisfaction has simultaneously increased, and research has demonstrated that exposure to images of extremely muscular models contributes to body dissatisfaction and muscle dysmorphia in young men," they wrote.
For the current study, they gathered data through the Eating and Activity in Teens (EAT 2010) study, a large, population-based study of weight status, dietary intake, physical activity, weight control behaviors, and related factors for adolescents from the Minneapolis and St. Paul metropolitan area during the 2009 to 2010 school year.
The study included a 235-question self-report survey and physical measurements of participants height and weight.
The authors focused on participant response to questions related to frequency of participation in any of five muscle-enhancing behaviors over the year prior to the survey, including altered eating behaviors and exercising more -- considered "healthy" behaviors as well as use of protein powder or shakes, use of steroids, or use of other muscle-building substances, such as creatine, amino acids, or growth hormones, considered "unhealthy" behaviors.
Participants also reported their school level, gender, race, socioeconomic status based on parental educational attainment, body mass index (BMI), sports team participation, and weight status.
The study population consisted of 2,793 students with a mean age of 14.4 and almost equally divided among females (53.2 percent) and males (46.8 percent). Nearly 30 percent of the participants were black and about 20 percent were white or Asian.
Almost 60 percent of the study population played at least one after-school sport.
Among boys, the authors found that more than two-thirds reported changing their eating to increase their muscle size or tone, and 90 percent exercised more to increase their muscle mass or tone. In terms of the prevalence of "unhealthy" behaviors:
34.7 percent reported using protein powders or shakes
5.9 percent reported using steroids
10.5 percent reported using some other muscle-enhancing substance
Among the girls, 21.2 percent reported using protein powders, while 4.6 percent said they used steroids, and 5.5 percent used other muscle-enhancing substances.
The authors also found that overweight and obese girls had significantly greater odds of using protein powders or shakes than girls of average BMI.
After adjusting for all covariates, the authors found high school boys were 70 percent more likely than other participants to use protein shakes and powders and other muscle-enhancing substances.
Asian males were more likely to use steroids compared with white males, while Asian females had around a greater chance of using steroids or other muscle-enhancing substances.
Both girls and boys who participated on a sports team were significantly more likely to engage in all muscle-enhancing behaviors besides taking steroids and, among girls, other muscle-enhancing substances.
The authors noted that the study sample from a single U.S. state may not be generalizable, and that study measures of muscle-enhancing behavior were self-reported.
Nonetheless, "pediatricians and other healthcare providers should ask their adolescent patients about muscle-enhancing behaviors," they advised. "Healthcare providers should counsel adolescent patients about appropriate exercise, general nutrition, and the lack of efficacy and potential dangers of muscle-enhancement products."
They added that future research could include more detailed assessments of participants' body composition and weight.