Nutrition Knowledge and Supplement Use among Elite U.S. Army Soldiers

Military Medicine, Dec 2003 by Bovill, Maria E, Tharion, William J, Lieberman, Harris R

A U.S. Army Special Forces (SF) unit was studied to determine characteristics of supplement users, assess nutrition knowledge, and identify nutrition information sources. SF-qualified (n = 119) and non-SF, support soldiers (n = 38) participated. Most soldiers (87%) reported current supplement use with more SF (90%) than non-SF, support soldiers (76%) using supplements (p

Introduction

U.S. Army Special Forces (SF) are elite military units that must maintain operational readiness for short-notice deployment. Physical training is frequent and includes distance running and sprinting, distance marching with rucksacks, swimming, weight lifting, climbing, and parachuting. They must be able to recover quickly between training sessions to sustain these physical demands. SF are often compared with competitive athletes and may adopt similar nutritional strategies. Sobal and Marquait1 reviewed 51 studies of vitamin/mineral supplement use by athletes and estimated a 46% mean prevalence. Elite athletes at national, international, and Olympic levels had a mean supplement use of 59%, higher than both college (43%) and high school (47%) athletes and the general population (35-40%). Research with U.S. Army soldiers indicates that 64% in SF and Ranger selection and training schools consume supplements.2 Supplement use among SF who have completed initial selection courses and have been assigned to operational units has not been reported.

In the United States, supplement sales have grown almost 80% from $8.8 billion in 1994 to $15.7 billion in 2000.3 In 1999, Americans spent approximately $1.4 billion on sports supplements and approximately 1.2 million people reported regular use.4 However, individuals with limited nutrition knowledge (NK) may be influenced by misinformation, leading to practices that could impair performance, be detrimental to their health, or simply waste money. Studies of athletes, coaches, and trainers indicate they exhibit low NK and often believe in questionable nutrition practices.5,6 The limited information available regarding NK of military personnel indicates they also possess low levels of NK,7,8 but NK of operational SF units has not been assessed.

Methods

Subjects

Volunteers recruited from an SF unit were SF-qualified soldiers and non-SF-qualified, support soldiers (SP). SP provide logistical and administrative support, but they do not participate in the same intensive training as SF-qualified soldiers. Because women are excluded from SF units, all subjects were men. A total of 176 soldiers volunteered between November 1999 and July 2000; however, due to incomplete or nonresponses, the final sample consisted of 157 subjects.

Materials

A questionnaire was administered to obtain demographic, medical history, health habits, and supplement use information. Supplement use categories were: never, past but not present, occasionally (less than once/week), frequently (one to six times/week), and daily. NK was assessed by modification of a previously developed questionnaire.5 Our questionnaire contained 54 items focusing on five sports nutrition subtopics: general nutrition, supplementation, special dietary considerations, pre-event meals, and fluid and hydration. Additional questions inquired about nutrition information sources.

Data Analyses

Data were analyzed using the Statistical Program for Social Sciences software (version 10.0, SPSS, Chicago, Illinois). Subjects were classified as supplement users (SU) if they used supplements at all at the time the questionnaire was administered. Descriptive data are reported as means � SD or frequencies and percentages. Groups compared were SF with SP and SU to nonusers (NU). Analyses of variance, [chi]^sup 2^ analyses, and Fisher's exact test were performed to determine mean differences for demographic and health habit variables and supplement use frequency by military group (SF vs. SP). Fisher's exact test was used instead of Pearson's [chi]^sup 2^ for 2 � 2 tables that did not meet [chi]^sup 2^ size requirements.9 NK scores were categorized as highest 50% and lowest 50% of scores. Logistic regression was performed to determine significant predictors of supplement use from demographic variables and various NK scores. This model used the same definition of supplement use as above but eliminated subjects who reported only using carbohydrate replacement drinks, bars, and gels because many consume these products not as a supplement but just as a beverage or food. Statistical significance was set at p

Results

SF were older (p

Supplement Use

Most (87%) soldiers reported using supplements at least occasionally, although SF reported more frequent use than SP: 90 vs. 76%, respectively (p

Exercise frequency (the number of times per week a soldier ran, swam, weight trained, or did other physical exercise) and NK percent correct responses were predictive of supplement use and determined by logistic regression (p

Nutrition Knowledge

SUs had a higher NK score than NU (p

NK scores differed by exercise frequency (p