Vitamin/mineral supplement use among high school athletes

Adolescence, Winter, 1994 by Jeffery Sobal, Leonard F. Marquart

INTRODUCTION

Vitamin and mineral supplements are commonly consumed in the United States with about 35-40% of the general population using them (McDonald 1986; Stewart, McDonald, Levy, Schuker, & Henderson, 1985). Fewer adolescents consume supplements than do adults, with about 20-25% of adolescents using them (Sobal & Muncie, 1988). However, adolescent athletes may be greater consumers of supplements than other groups.

Only four studies provide prevalence data on supplement consumption among high school athletes, reporting that 56% (Douglas & Douglas, 1984), 46% (Parr, Porter, & Hodgson, 1984), 33% (Krowchuk, Anglin, Goodfellow, Stancin, Williams, & Zimet, 1989), and 23% (Moffatt, 1984) used supplements. While three of these studies used large samples of adolescents, the Moffatt (1984) paper was an analysis of 13 elite high school gymnasts. The wide-ranging findings of these studies show that currently there is little consensus about the prevalence of supplement use by high school athletes. Supplement use by high school athletes tends to be lower than that of college and elite athletes (Sobal & Marquart, 1994).

Prior studies of supplement consumption among high school athletes did not examine influences or reasons for use. Other data reveal that boys participating in sports take supplements more often than do boys not involved in athletics (Fleischer & Read, 1982), suggesting that athletic participation may be a motivation for consumption. Alternatively, concern about general health may be a primary motivation. The present investigation examined reasons for supplement use in order to address the importance of motivations based on both athletic performance and health. Influences upon supplement use may originate from health-based sources, such as coaches. The relative importance of these and other influences were examined.

In recent years, women have increased their participation in sports at all levels. Studies of supplement use in the general population (McDonald 1986; Stewart et al. 1985) and among adolescents (Sobal & Muncie, 1988) tend to report that women are more likely to consume supplements than are men. The female gender role is more closely tied to food and nutrition, and supplement use appears to be an expression of these health concerns. The age at which gender differences in supplement consumption begin is not clear. Among athletes supplement use may not follow the gender patterns of the general population, with the emphasis upon athletic performance and competition traditionally more closely related with the male gender role. Existing studies do not analyze gender differences in high school athletes' supplement use (Douglas & Douglas, 1984; Parr et al. 1984; Krowchuk et al., 1989). This investigation examined gender differences in supplement use among adolescent athletes to investigate whether more female-based health roles or more male-based athletic competition roles are more important.

Athletes participate in a variety of sports and have varying aspirations for achievement. Belief that vitamin and mineral supplements enhance athletic performance is common, and athletes often consume supplements as ergogenic aids despite the consensus in the nutrition literature that supplements do not help performance (Haymes, 1991). Athletes who aspire to compete at higher levels of sport may be more likely to use supplements as ergogenic aids because of their athletic ambitions. This study also examined belief about the value of supplements for athletic performance, differences in the consumption of supplements by type of sport, and variations in supplement consumption between high school athletes who plan to compete at the college level and those who do not have higher athletic aspirations.

Prior studies of supplement consumption among medical patients found that those in rural areas were less likely to consume supplements than were their urban or suburban counterparts (Sobal, Muncie, & Guyther, 1986). Many practices, such as health behaviors and techniques for athletic training, may be slower to diffuse into rural areas and be adopted later by rural residents than by those who live in urban settings (Rogers, 1983). This investigation further examined high school athletes in a rural area to provide comparative information with prior studies of adolescents (Douglas & Douglas, 1984; Parr et al., 1984; Krowchuk et al., 1989).

METHOD

A questionnaire was developed based on prior literature on vitamin/mineral supplement consumption (McDonald 1986; Stewart et al., 1985) and the authors' experience in adolescent nutrition and athletics. The questionnaire was pretested on adolescents and examined by professional colleagues for content validity. Demographic questions assessed the athletes' gender, grade in school, sports team participation, major sport, and aspiration to participate in college sports. Supplement use questions asked athletes if they take vitamin/mineral supplements, how often they take them, how long they have been taking them, which of ten supplements they take, the importance of six reasons for using supplements, and to rate the level of influence of seven factors on supplement use. One question asked if they thought taking vitamin/mineral supplements could help athletes perform better in their sport.