Navy Seals Nutritional Supplements Articles & Resources

In the United States, supplement sales have grown almost 80% from $ billion in 1994 to $ billion in In 1999, Americans spent approximately $ billion on sports supplements and approximately million people reported regular 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 ,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 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 , 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 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

Most frequently reported nutrition information sources for all soldiers were magazines/books, friends, and teammates (Fig. 2). SF were less likely than SP to report using the Internet (27 vs. 45%, respectively, p

The mean scores of the five NK subtopics are presented in Table IV. Soldiers performed best on fluid and hydration questions with 82% answering at least one-half of the questions correctly; only 38% of soldiers answered one-half of the prior event meal questions correctly.

Discussion

Supplement Use

SF represent a unique military population and exhibit some behaviors similar to those of competitive athletes. A higher proportion of soldiers used supplements than previously reported in SUs exercised more frequently and had greater NK than NU, whereas in previous studies, predictors of SU have been age, education greater than 12 years, higher income, and positive lifestyle factors such as Overall, SU chose supplements such as multivitamins, sports bars/drinks, and vitamin C, which are widely regarded as safe and may be beneficial to meet their physical training needs. These supplements are similar to choices reported previously by elite military personnel and ,2,13

SF in this study are graduates of the . Army SF training school, where there was a lower incidence (64%) of supplement use than observed in the present study (90%).2 The difference between SF students and SF-qualified soldiers may reflect an increase in use over time, because the SF student study was conducted in Additionally, there may be a trend in the SF culture that as SF students become SF qualified, more of them become SU. Consistent with this explanation, supplement use among the elite . Navy SEALs (78%) was similar to the incidence we observed in Because there was a significant difference between SF and SP and from previously cited rates of supplement use, it appears that Special Operations Forces (., SF and Navy SEALs) use supplements more often than other soldiers and ,14

Nutrition Knowledge

There is limited data available on military populations' NK. A report on over 3,000 Navy sailors found they responded correctly to approximately 40 to 65% of nutrition ,8 In comparison, NK studies of college athletes found they responded correctly approximately 34 to 52% of the ,16 Previous research has not demonstrated a positive correlation between supplement use and NK;11,17 however, in this study, NK was a predictor of supplement use, and SU had significantly higher NK than NU.

There is confusion about the role of protein in performance in this population, similar to a prior study of Many soldiers (65%) incorrectly believe that for short-term athletic events, energy comes from amino acids. Whereas only 22% of soldiers reported using protein supplements and the amounts consumed are unknown, it is troubling that most soldiers do not understand the function of the supplements they use. Of concern is that if soldiers are consuming large amounts of protein supplements, it will increase their already elevated fluid needs during training. Additionally, the safety and efficacy of consuming individual amino acids has not yet been proven in research studies of adequately nourished

Fifty-eight percent of SF and SP responded that vitamins provide energy. These soldiers may be misled into assuming their energy intake will be provided by a vitamin supplement. An energy deficit may result in muscle mass loss, increased fatigue, injury, and illness,4 all of which would be detrimental to performance and mission success.

The beneficial effects of most supplements used by those who are well-nourished are not known; however, multivitamin supplementation by individuals who lack certain vitamins or minerals in their diet is certainly warranted. The use of carbohydrate supplementation in the form of drinks, bars, or gels is advocated for those with high-energy needs, such as the SF. These results suggest that in general, these soldiers are often consuming appropriate supplements for their health and performance. It is encouraging that a high percentage of soldiers will take supplements if they were found to be beneficial to their health or job performance.

In a nationwide survey by the American Dietetic Association,20 92% of respondents agreed that "registered dietitians, nutritionists, and doctors are people's most-valued sources of nutrition information"; however, primary sources reported for nutrition information were television and magazines. Similarly, in this study, only a small number of soldiers sought out these professionals for nutrition information. Because NK in this study was low, combined with obtaining nutrition information from nonprofessional sources, the Department of Defense medical professionals must bridge the gap to proper nutrition by directing soldiers to easy to read nutritionally sound magazines. Other efforts could include briefings to command personnel on proper nutrition, as word-of-mouth nutrition information is often obtained through friends and colleagues. Nutrition education for SF, some of the most active soldiers in the military, could significantly enhance their health, physical training, and ultimately mission success. Realizing that most soldiers may not seek qualified medical personnel such as dietitians to obtain information is a barrier that military dietitians must overcome to ensure soldiers' NK and subsequent eating behaviors are healthy.

Acknowledgments

We thank Susan McGraw for assistance with data analyses and Carol Baker-Fulco for support on-site during data collection. This work was supported by the . Army Medical Research and Materiel Command.

References

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Guarantor: MAJ Maria E. Bovill, SP USA

Contributors: MAJ Maria E. Bovill, SP USA; William J. Tharion, MS MBA; Harris R. Lieberman, PhD

Military Nutrition Division, . Army Research Institute of Environmental Medicine, Nauck, MA 01760.

The views, opinions, and/or findings in this report are those of the authors and should not be construed as an official Department of the Army position, policy, or decision, unless so designated by other official documentation. Human subjects participated in this study after giving free and informed consent. Investigators adhered to regulations described in the appropriate documents, . Army Regulation 70-25 and . Army Medical Research and Materiel Command Regulation 70-25 on Use of Volunteers in Research. For the protection of human volunteers, the investigators adhered to policies of applicable Federal Law CFR 46. Citation of commercial organizations and trade names in this report do not constitute an official Department of the Army endorsement or approval of the products or services of these organizations.

Reprints: William J. Tharion, Military Nutrition Division, . Army Research Institute of Environmental Medicine, 42 Kansas St., Natick, MA 01760-5007.

This manuscript was received for review in October 2002. The revised manuscript was accepted for publication in March 2003.