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Dietary Supplement Use in US Army Personnel: A Mixed-Methods, Survey and Focus-Group Study Examining Decision Making and Factors Associated With Use

Open AccessPublished:February 27, 2021DOI:https://doi.org/10.1016/j.jand.2021.01.011

      Abstract

      Background

      Dietary supplement (DS) use by Army personnel is high and is a safety and readiness issue.

      Objective

      Our aim was to examine factors motivating use of DSs among US Army personnel and preferred safety education strategies.

      Design

      This mixed-method study used a validated DS questionnaire and subsequent focus groups that were formed based on questionnaire-identified demographic characteristics. An embedded qualitative dominant design was used.

      Participants/setting

      Data were collected from April to July 2015 from active duty soldiers at 3 military installations in the United States.

      Main outcome measures

      A self-report questionnaire (n = 289) provided data on demographic characteristics, health, exercise, detailed use, and attitudes regarding DS safety and efficacy. Fourteen focus-group sessions (n = 129) examined factors motivating DS use, education strategies, and identified themes and DS-related behaviors.

      Statistical analysis performed

      Descriptive statistics and χ2 analyses were conducted.

      Results

      Of the soldiers who completed questionnaires, 83% were male, 60% were enlisted, and 40% were officers; mean age ± standard deviation was 27.6 ± 0.36 years and 75% used at least 1 type of DS per week: 52% used protein/amino acids, 47% used multivitamins/minerals, and 35% used a combination of products. Focus groups indicated reasons for use included physical appearance, fitness, peer endorsement, ease of access, limited availability of healthy food, occupational demands, and health. Participants requested education from an expert on safe use that was not focused on dangerous products.

      Conclusions

      Soldiers are high DS users, especially products marked for purported performance enhancement. Motivating factors for DS use are fitness/appearance and occupational demands, but soldiers lack knowledge of DS regulatory requirements and safety/efficacy. Soldiers wished to receive education on DSs from trusted health care professionals, such as registered dietitian nutritionists, that was not focused on dangerous products. Study findings suggest guidance and education should occur before periods of high DS use, such as deployment.

      Keywords

      The Continuing Professional Education (CPE) quiz for this article is available for free to Academy members through the MyCDRGo app (available for iOSand Android devices) and through www.jandonline.org (click on “CPE” in the menu and then “Academy Journal CPE Articles”). Log in with your Academy of Nutrition and Dietetics or Commission on Dietetic Registration username and password, click “Journal Article Quiz” on the next page, then click the “Additional Journal CPE quizzes” button to view a list of available quizzes.Non-members may take CPE quizzes by sending a request to [email protected] . There is a $45 fee per quiz (includes quiz and copy of article) for non-members. CPE quizzes are valid for 3 years after the issue date in which the articles are published.
      Research Question: What are the underlying factors motivating use of dietary supplements among US Army personnel, as well as their preferred safety education strategies?
      Key Findings: A mixed-methods study was conducted with US Army personnel that used a dietary supplements questionnaire (n = 289) and focus groups (14 sessions, n = 129). The questionnaire data showed the majority (75%) used at least 1 dietary supplement once per week. Focus groups revealed reasons for use included physical appearance, achieving personal and professional fitness goals, endorsement by peers, ease of access, limited access to healthy food, occupational demands, and health outcomes. Soldiers preferred receiving dietary supplements from trusted health care providers with expertise in nutrition and fitness education early in their military careers and before deployment.
      Appproximately 50% of US adults use dietary supplements (DSs) regularly,
      • Gahche J.J.
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      Federal monitoring of dietary supplement use in the resident, civilian, noninstitutionalized US Population, National Health and Nutrition Examination Survey.
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      • Jun S.
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      Dietary supplement use differs by socioeconomic and health-related characteristics among U.S. adults, NHANES 2011-2014.
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      • Giovannucci E.L.
      Trends in dietary supplement use among us adults from 1999-2012.
      and use by Army personnel is higher than by civilians, as approximately 63% of soldiers report using them at least once or more per week.
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      • White A.
      • Hadden L.S.
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      Use of dietary supplements among active-duty US Army soldiers.
      ,
      • Austin K.G.
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      • Farina E.K.
      • McGraw S.M.
      • Lieberman H.R.
      Soldier use of dietary supplements, including protein and body building supplements, in a combat zone is different than use in garrison.
      DS use among military personnel is well documented by recent studies.
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      • Stavinoha T.B.
      • McGraw S.M.
      • White A.
      • Hadden L.S.
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      Use of dietary supplements among active-duty US Army soldiers.
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      Predictors of dietary supplement use by U.S. Coast Guard personnel.
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      Dietary supplement use in a large, representative sample of the US Armed Forces.
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      Protecting military personnel from high risk dietary supplements.
      • Kegel J.L.
      • Kazman J.B.
      • Scott J.M.
      • Deuster P.A.
      Health behaviors and psychosocial attributes of US soldiers.
      A systematic review reported prevalence of DS use among military personnel across all services to be approximately 61%.
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      • Farina E.K.
      • Austin K.G.
      • Lieberman H.R.
      A systematic review and meta-analysis on the prevalence of dietary supplement use by military personnel.
      The use of DSs among military personnel appears to increase during deployment.
      • Boos C.J.
      • Simms P.
      • Morris F.R.
      • Fertout M.
      The use of exercise and dietary supplements among British soldiers in Afghanistan.
      • Baker B.
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      Prevalence and predictors of dietary and nutritional supplement use in the Australian Army: A cross-sectional survey.
      • Varney S.M.
      • Ng P.C.
      • Perez C.A.
      • et al.
      Self-reported dietary supplement use in deployed United States service members pre-deployment vs. during deployment, Afghanistan, 2013-2014.
      In a survey administered more than 10 years ago, 60% of soldiers taking DSs did so to promote general health, 31% to provide more energy, and 24% to increase muscle strength.
      • Lieberman H.R.
      • Stavinoha T.B.
      • McGraw S.M.
      • White A.
      • Hadden L.S.
      • Marriott B.P.
      Use of dietary supplements among active-duty US Army soldiers.
      However, DS use for the purpose of performance enhancement has been increasing.
      • Austin K.G.
      • McLellan T.M.
      • Farina E.K.
      • McGraw S.M.
      • Lieberman H.R.
      Soldier use of dietary supplements, including protein and body building supplements, in a combat zone is different than use in garrison.
      ,
      • Kegel J.L.
      • Kazman J.B.
      • Scott J.M.
      • Deuster P.A.
      Health behaviors and psychosocial attributes of US soldiers.
      ,
      • Austin K.G.
      • Price L.L.
      • McGraw S.M.
      • McLellan T.M.
      • Lieberman H.R.
      Longitudinal trends in use of dietary supplements by U.S. Army personnel differ from those of civilians.
      Most military personnel take more than 1 DS per week and use appears to be increasing over time.
      • Knapik J.J.
      • Austin K.G.
      • Farina E.K.
      • Lieberman H.R.
      Dietary supplement use in a large, representative sample of the US Armed Forces.
      ,
      • Austin K.G.
      • Price L.L.
      • McGraw S.M.
      • McLellan T.M.
      • Lieberman H.R.
      Longitudinal trends in use of dietary supplements by U.S. Army personnel differ from those of civilians.
      A review by Dickinson and MacKay
      • Dickinson A.
      • MacKay D.
      Health habits and other characteristics of dietary supplement users: A review.
      reported civilian Americans generally use DSs for their supposed health benefits. Studies indicate DS consumers are more conscientious about health and wellness than non-DS users and identified health consciousness as a significant predictor of attitudes toward supplements.
      • Willis E.
      • Royne M.
      Health consciousness or familiarity with supplement advertising: What drives attitudes toward dietary supplements?.
      However, use of many types of DSs is not supported by sufficient evidence and some DSs can have adverse effects on health.
      • Cohen P.A.
      The supplement paradox: Negligible benefits, robust consumption.
      ,
      • Cohen P.A.
      Hazards of hindsight—monitoring the safety of nutritional supplements.
      Many consumers mistakenly believe DSs are regulated for safety and efficacy in the same way that nonprescription and prescription drugs are regulated by the Food and Drug Administration (FDA).
      • Carvey C.E.
      • Farina E.K.
      • Lieberman H.R.
      Confidence in the efficacy and safety of dietary supplements among United States active duty army personnel.
      However, the Dietary Supplement Health and Education Act of 1994 defined DSs as products containing 1 or more dietary ingredients intended to supplement the diet and increase dietary intake rather than as drugs or medical devices. The statute does not require manufacturers to demonstrate safety or efficacy before DSs are placed on the market.
      Dietary Supplements. US Food and Drug Administration.
      FDA regulation prohibits manufacturers and distributors from selling misbranded and adulterated DSs, but the burden of proof is on the FDA to provide sufficient evidence that a marketed DS is unsafe or causes illness or injury before the product can be legally removed from the market.
      Many soldiers and civilians misunderstand or lack knowledge about DS efficacy and safety. Case reports and surveys demonstrate adverse effects of DS use in soldiers are common and often caused by the ingestion of a specific ingredient in a supplement.
      • Deuster P.A.
      • Lieberman H.R.
      Protecting military personnel from high risk dietary supplements.
      ,
      • Carol M.L.
      Hydroxycut weight loss dietary supplements: A contributing factor in the development of exertional rhabdomyolysis in three U.S. Army soldiers.
      • Eliason M.J.
      • Eichner A.
      • Cancio A.
      • Bestervelt L.
      • Adams B.D.
      • Deuster P.A.
      Case reports: Death of active duty soldiers following ingestion of dietary supplements containing 1,3-dimethylamylamine (DMAA).
      • Lieberman H.R.
      • Austin K.G.
      • Farina E.K.
      Surveillance of the armed forces as a sentinel system for detecting adverse effects of dietary supplements in the general population.
      One study assessed soldiers’ confidence in the safety and efficacy of DSs and knowledge of federal DS regulatory requirements and found most soldiers were confident DSs perform as advertised and are safe to consume.
      • Carvey C.E.
      • Farina E.K.
      • Lieberman H.R.
      Confidence in the efficacy and safety of dietary supplements among United States active duty army personnel.
      Like civilians, most soldiers had a limited or inaccurate knowledge of federal DS regulatory requirements. Fewer than one-half of the soldiers surveyed in that study were aware that the government does not require DS manufacturers to conduct efficacy trials of their products.
      • Carvey C.E.
      • Farina E.K.
      • Lieberman H.R.
      Confidence in the efficacy and safety of dietary supplements among United States active duty army personnel.
      A comprehensive report by the Committee on Dietary Supplements Use by Military Personnel of the Institute of Medicine noted the extensive use of DSs and stated there is a critical requirement to evaluate the long-term safety and efficacy of DSs in the military population.
      • Greenwood M.R.C.
      • Oria M.
      Given the extensive use of DSs by soldiers and other military personnel and concern about the benefits and efficacy of DSs, it is necessary to understand why soldiers choose to consume DSs and are willing to spend a great deal of money to obtain them.
      • Lieberman H.R.
      • Stavinoha T.B.
      • McGraw S.M.
      • White A.
      • Hadden L.S.
      • Marriott B.P.
      Use of dietary supplements among active-duty US Army soldiers.
      Along with high use of DSs among military personnel, the types of DSs they select appear to be more risky or dangerous than those typically used by the civilian population.
      • Lieberman H.R.
      • Stavinoha T.B.
      • McGraw S.M.
      • White A.
      • Hadden L.S.
      • Marriott B.P.
      Use of dietary supplements among active-duty US Army soldiers.
      ,
      • Deuster P.A.
      • Lieberman H.R.
      Protecting military personnel from high risk dietary supplements.
      ,
      • Lieberman H.R.
      • Austin K.G.
      • Farina E.K.
      Surveillance of the armed forces as a sentinel system for detecting adverse effects of dietary supplements in the general population.
      A cross-sectional study with data from approximately 300,000 soldiers found those engaged in high-intensity interval training and exhibiting healthy behaviors often consumed weight-loss and performance-enhancing DSs.
      • Kegel J.L.
      • Kazman J.B.
      • Scott J.M.
      • Deuster P.A.
      Health behaviors and psychosocial attributes of US soldiers.
      To our knowledge, the study presented here is the first mixed-method, qualitative study using focus-group methodology to investigate factors motivating use of DSs in an at-risk military population. A detailed and standardized DS questionnaire
      • Caldwell J.A.
      • McGraw S.M.
      • Thompson L.A.
      • Lieberman H.R.
      A survey instrument to assess intake of dietary supplements, related products, and caffeine in high-use populations.
      was also administered to a larger population sample. The objective was to examine the underlying factors motivating use of DSs among Army personnel and explore attitudes and preferred safety education strategies for DS use.

      Methods

      Study Design and Participants

      This was a cross-sectional mixed-methods study that initially administered a standardized, validated questionnaire
      • Caldwell J.A.
      • McGraw S.M.
      • Thompson L.A.
      • Lieberman H.R.
      A survey instrument to assess intake of dietary supplements, related products, and caffeine in high-use populations.
      and, based on responses to the questionnaire, selected a smaller group of volunteers for focus-group participation based on preselected demographic factors. The survey was the quantitative, recessive strand element of the study. The focus groups were the qualitative, dominant strand of the study.
      • Zoellner J.
      • Harris J.E.
      Mixed-methods research in nutrition and dietetics.
      The focus-group approach was based on a phenomenology strategy
      • Harris J.E.
      • Gleason P.M.
      • Sheean P.M.
      • Boushey C.
      • Beto J.A.
      • Bruemmer B.
      An introduction to qualitative research for food and nutrition professionals.
      that assessed the participants’ attitudes, perceptions, and experiences regarding DSs.
      The questionnaire gathered information on demographic characteristics, lifestyle factors, and frequency and types of DSs used.
      • Zoellner J.
      • Harris J.E.
      Mixed-methods research in nutrition and dietetics.
      The study was conducted at 3 military installations in the United States, and recruited active duty soldiers 18 years and older from combat arms, combat support, and combat service support occupations. Data were collected from April to July 2015 using a questionnaire at each site followed by focus-group sessions. Approximately 300 soldiers attended briefings, 291 consented, and 2 withdrew after consenting. Therefore, 289 completed the quantitative questionnaire and all provided usable data. The focus groups were formed using the homogenous sampling method based on demographic criteria of rank, sex, and DS use. These focus groups consisted of all male, all females, both sexes, DS users, nonusers, and mixed DS users and nonusers within different ranks (junior enlisted, senior enlisted, junior officers, and senior officers). Participants were excluded if they were engaged in selling DSs. Study site selection was coordinated through a centralized Army command to obtain a sample that would be representative of the active duty Army and the research team would receive unit administrative support. Participation was voluntary. This study was approved as an expedited protocol by the Human Use Review Committee of the US Army Research Institute of Environmental Medicine, Natick, MA, and all participants provided written informed consent.

      Sample Size Estimation for Survey and Focus Groups

      A sample size of 288 was required for the survey based on a 95% CI, a soldier population of 480,000—the approximate number of active duty soldiers
      • Cancian M.F.
      U.S. Military Forces in FY 2020: Army.
      —and an estimated outcome factor of 75% ± 5% of soldiers consuming DSs. Military personnel are far more homogeneous than the general population due to enlistment criteria and retention standards, such as age.

      Beaver KM, Barnes JC, Schwartz JA, Boutwell BB. Enlisting in the military: The influential role of genetic factors. SAGE Open. April 13, 2015. https://doi.org/10.1177/2158244015573352

      Moreover, cross-service comparisons of military supplement use have found <6% variation among Army, Air Force, and Coast Guard personnel.
      • Caldwell J.A.
      • McGraw S.M.
      • Thompson L.A.
      • Lieberman H.R.
      A survey instrument to assess intake of dietary supplements, related products, and caffeine in high-use populations.
      Surveying a small portion of any given military population produces results that accurately generalize to the remainder of the entire Army compared with surveys conducted on the general US population. To recruit volunteers for this study, large groups of soldiers were briefed in person by study personnel in a single venue about study requirements. Potential volunteers were recruited personally, not by mail, over the internet, or by advertisements. In addition, if a soldier volunteered, he or she would be relieved of their regular duties to participate in the questionnaire and, if selected, a focus group. The survey methodology used was validated in prior investigations of the Army and other military services,
      • Lieberman H.R.
      • Stavinoha T.B.
      • McGraw S.M.
      • White A.
      • Hadden L.S.
      • Marriott B.P.
      Use of dietary supplements among active-duty US Army soldiers.
      ,
      • Austin K.G.
      • Price L.L.
      • McGraw S.M.
      • Lieberman H.R.
      Predictors of dietary supplement use by U.S. Coast Guard personnel.
      ,
      • Lieberman H.R.
      • Marriott B.P.
      • Williams C.
      • et al.
      Patterns of dietary supplement use among college students.
      • Austin K.G.
      • McGraw S.M.
      • Lieberman H.R.
      Multivitamin and protein supplement use is associated with positive mood states and health behaviors in US Military and Coast Guard personnel.
      • Knapik J.J.
      • Trone D.W.
      • Austin K.G.
      • Steelman R.A.
      • Farina E.K.
      • Lieberman H.R.
      Prevalence, adverse events, and factors associated with dietary supplement and nutritional supplement use by US Navy and Marine Corps personnel.
      reducing administrative inconsistencies and questionnaire-item misinterpretation by an iterative process.
      • Caldwell J.A.
      • McGraw S.M.
      • Thompson L.A.
      • Lieberman H.R.
      A survey instrument to assess intake of dietary supplements, related products, and caffeine in high-use populations.
      Determination of the appropriate number of focus groups, and their size and composition, was based on several external standards and parameters necessary to achieve the study’s objectives. Hennink and colleagues
      • Hennink M.M.
      • Kaiser B.N.
      • Weber M.B.
      What influences saturation? Estimating sample sizes in focus group research.
      determined a high degree of code saturation, the point at which no additional issues were identified in the data, would be attained with 4 focus groups. Also, that the majority of meaning saturation, the point at which the issues identified were fully understood and no additional insights were found, would be achieved with 4 to 6 focus groups. For this study, to insure an adequate and representative sample participated, a total of 14 focus-group sessions (n = 129) were conducted, 5 sessions each at 2 military installations, and 4 sessions at 1 installation using a homogenous sampling method.
      • Harris J.E.
      • Gleason P.M.
      • Sheean P.M.
      • Boushey C.
      • Beto J.A.
      • Bruemmer B.
      An introduction to qualitative research for food and nutrition professionals.
      The determination to include approximately 10 participants (but no more) in each of these groups was based on guidance from Krueger and Casey,
      • Krueger R.A.
      • Casey M.A.
      Participants in a focus group.
      who stated that the traditionally recommended group size is 10 to 12 people, and it is unwise to study groups with more than 10 participants because “large groups are difficult to control and they limit each person’s opportunity to share insights and observations” (p. 67). The focus-group sample size was conservative and based on published studies using focus groups of 10 to 60 participants to investigate health-related outcomes.
      • Boddy L.M.
      • Knowles Z.R.
      • Davies I.G.
      • et al.
      Using formative research to develop the healthy eating component of the CHANGE! school-based curriculum intervention.
      • Nolan-Clark D.J.
      • Neale E.P.
      • Probst Y.C.
      • Charlton K.E.
      • Tapsell L.C.
      Consumers' salient beliefs regarding dairy products in the functional food era: A qualitative study using concepts from the theory of planned behaviour.
      • O'Dougherty M.
      • Kurzer M.S.
      • Schmitz K.H.
      Shifting motivations: Young women's reflections on physical activity over time and across contexts.
      • Jones S.A.
      • Walter J.
      • Soliah L.
      • Phifer J.T.
      Perceived motivators to home food preparation: Focus group findings.
      A recent focus-group study of caffeine-containing product use by Army aircrew personnel conducted by our laboratory using the same methods generated various themes and achieved theme saturation with 5 sessions and a total of 47 participants.
      • Bukhari A.S.
      • Caldwell J.A.
      • DiChiara A.J.
      • et al.
      Caffeine, energy beverage consumption, fitness, and sleep in U.S. Army Aviation personnel.
      A total of 128 soldiers participated in focus groups, out of 150 who were invited based on their questionnaire-determined demographics. One volunteer withdrew after reporting to a focus-group session.

      Questionnaire

      The survey questionnaire was used to obtain demographic information, identify participants to assign to specific focus-group sessions, and collect detailed information on DS use. The questionnaire was a modified version of a validated, standardized questionnaire used for studies conducted by the US Army Research Institute of Environmental Medicine, which is available to the public.
      • Lieberman H.R.
      • Stavinoha T.B.
      • McGraw S.M.
      • White A.
      • Hadden L.S.
      • Marriott B.P.
      Use of dietary supplements among active-duty US Army soldiers.
      ,
      • Austin K.G.
      • Price L.L.
      • McGraw S.M.
      • Lieberman H.R.
      Predictors of dietary supplement use by U.S. Coast Guard personnel.
      ,
      • Caldwell J.A.
      • McGraw S.M.
      • Thompson L.A.
      • Lieberman H.R.
      A survey instrument to assess intake of dietary supplements, related products, and caffeine in high-use populations.
      ,
      • Lieberman H.R.
      • Marriott B.P.
      • Williams C.
      • et al.
      Patterns of dietary supplement use among college students.
      ,
      • Austin K.G.
      • Price L.L.
      • McGraw S.M.
      • et al.
      Demographic, Lifestyle factors, and reasons for use of dietary supplements by Air Force personnel.
      The questionnaire consisted of 45 questions on demographic characteristics, deployment, general health, fitness and exercise, dietary patterns, caffeine use, frequency and types of DSs used, reasons for DS use, negative effects experienced, sources of DS information, places of purchase, and expense of DS use. The questionnaire took approximately 40 minutes to complete electronically using Samsung Series 7 Slate tablets (Samsung Electronics).

      Focus Groups

      Content Validity and Reliability of Focus-Group Questions

      Before implementation, the focus-group questions were tested for validity and reliability. The research team generated a question bank based on previous literature and the detailed US Army Research Institute of Environmental Medicine questionnaire of demographics and DS use. These questions were reviewed by subject matter experts and the study team. The questions were then iteratively tested using 4 sequential pilot focus-group sessions to ensure proper framing of questions, sequencing, time allotment, and refinement.
      • Krueger R.A.
      • Casey M.A.
      Focus Groups: A Practical Guide for Applied Research.
      This process identified key areas of questioning, focus-group procedures, question comprehension, discussion flow, and session timing. The pilot tests established consistency of focus-group procedures across multiple focus-group moderators. Each focus group followed a general script of the following predetermined topics areas: definition of a DS; discussion of specific DSs used; use factors and decision making; desired effects and/or benefits of DS use on health and performance; confidence in perceived safety and efficacy of DSs; awareness/perception of information related to DSs; and potential for effective guidance and education on DSs.

      Focus-Group Procedures

      Each focus group was conducted in a closed classroom for approximately 90 minutes. Focus-group sessions were moderated by 1 of 3 study staff members with experience and expertise in focus-group facilitation. At the beginning of each session, participants were briefed on the purpose and focus-group rules, to include the following: introduction of study personnel; description of focus-group format; explanation of the use of recordings; respect of participant opinions and privacy; confidentiality of participant identities; and rights of participants to refrain from responding to questions and/or to leave the focus group without penalty. Focus groups were formed on the basis of military rank, sex, and use of DSs to reduce potential influences due to military rank structure and allow uninhibited sharing of DS-related experiences and attitudes. The moderators ensured participants had an opportunity to express their thoughts if they chose to do so and sessions were completed within a specified time period to respect participants’ attendance/participation and time. The researchers took steps to reduce bias by following standardized procedures and methods of questioning to address various topics areas, and questions were rehearsed during pilot testing to ensure reliability between moderators. Up to 5 sessions were conducted at each military installation to insure identification and saturation of themes.

      Data Analysis

      Questionnaire data were analyzed using IBM SPSS, version 21
      and Microsoft Excel 2007. The results of spending included data from participants who reported spending more than $0 and less than $242 per month. Outliers were removed when they reported spending more than 1.5 times the interquartile range above the 75th percentile. The filtered data were normally distributed. Data from focus groups were collected using field notes and audio and video recordings of each session. Numbered placards were used to identify participants on video recordings to associate individual focus-group comments with questionnaire responses, such as demographic and DS use data. Focus groups were transcribed verbatim from audio and video recordings by several different staff members, and all transcripts were imported into NVivo software, version 10,
      which is designed for qualitative analyses. Verbatim responses were coded for categories, patterns, and themes. An initial descriptive codebook was developed based on the main focus-group topic areas and themes that emerged during transcript reviews. The codebook themes were organized into major categories (parent nodes), with minor themes identified within each category (child nodes). Each theme node was defined by descriptions, as well as inclusion and exclusion criteria, to insure coding during analysis.
      Two researchers independently coded a subset of the data and reviewed coding decisions and differences as identified by the NVivo software.
      Interpretation discrepancies were addressed and resolved by further refining the codebook criteria to eliminate ambiguities, until inter-rater reliability agreement was >95%. Additional emergent themes were added to the codebook as warranted during this review process. Further coding occurred as an iterative process during data analysis. The data were evaluated by comparing participant responses within and between groups and analyzed by themes. Direct quotes were used to illuminate themes.

      Results

      Results From the Questionnaire

      Quantitative survey data were collected from 289 participants (83% male) from 3 military installations; Fort Campbell, KY (n = 100 [34.6%]), Fort Hood, TX (n = 89 [30.8%]), and Fort Riley, KS (n = 100 [34.6%]). The majority of participants (96%) were 40 years or younger, with a mean age ± standard deviation (SD) of 27.6 ± 0.36 years, mean body mass index ± SD of 26.5 ± 6.1, and 14% of participants had a body mass index ≥30.0. Approximately 50% of participants were from a combat arms occupation and had deployed a mean ± SD of 1.3 ± 1.5 times, lasting a mean ± SD of 12.5 ± 14.0 months (Table 1).
      Table 1Self-reported use of dietary supplements at least once per week during the prior 12 months, with demographic and fitness-related questionnaire responses, by US Army personnel (n = 289) participating in a mixed-methods study examining decision-making and factors associated with dietary supplement use
      VariableTotal, nDS
      DS = dietary supplement.
      user, n (%)
      MVI/MM
      MV/MM = multivitamin/multimineral.
      user, n (%)
      IV/M
      IV/M = individual vitamin and/or mineral.
      user, n (%)
      P/AA,
      P/AA = protein/amino acid supplement.
      user n (%)
      Combination of DSs, n (%)Other DS, n (%)
      ←n (%)→
      Total289216 (75)137 (47)73 (25)149 (52)101 (35)123 (43)
      Sex
      P < .05, based on χ2 test.
      P < .05, based on χ2 test.
      P < .01, based on χ2 test.
      P < .01, based on χ2 test.
      P < .05, based on χ2 test.
      Male241 (83)186 (77)116 (48)54 (22)136 (56)97 (40)109 (45)
      Female48 (17)30 (63)21 (44)19 (40)13 (27)4 (8)14 (29)
      Age group
      P < .01, based on χ2 test.
      P < .01, based on χ2 test.
      18-24 y116 (40)85 (73)52 (45)30 (26)68 (59)52 (45)53 (46)
      25-29 y87 (30)68 (78)41 (47)20 (23)50 (57)32 (37)30 (34)
      30-39 y75 (26)55 (73)37 (49)19 (25)31 (41)17 (23)35 (47)
      ≥40 y11 (4)8 (73)7 (64)4 (36)0 (0)0 (0)5 (45)
      Education
      P < .05, based on χ2 test.
      Some high school/high school graduate65 (22)44 (68)25 (38)15 (23)32 (49)23 (35)26 (40)
      Some college/Associate’s degree100 (35)72 (72)44 (44)22 (22)50 (50)43 (43)43 (43)
      Bachelor’s or graduate degree124 (43)100 (81)68 (55)36 (29)67 (54)35 (28)54 (44)
      Race/ethnicity
      P < .01, based on χ2 test.
      P < .01, based on χ2 test.
      P < .05, based on χ2 test.
      P < .05, based on χ2 test.
      White, not Hispanic169 (58)138 (82)88 (52)41 (24)98 (58)64 (38)84 (50)
      Black, not Hispanic52 (18)33 (63)19 (37)14 (27)15 (29)9 (17)17 (33)
      Hispanic, any race44 (15)31 (70)16 (36)9 (20)24 (55)20 (45)12 (27)
      Other23 (8)13 (57)13 (57)9 (39)11 (48)8 (35)9 (39)
      Rank group
      Junior Enlisted: E1-E4 (Private, Private Second Class, Private First Class, Specialist); Senior Enlisted: E5-E7 (Sergeant, Staff Sergeant, Sergeant First Class); Junior Officer: O1-O3 (Second Lieutenant, First Lieutenant, Captain); Senior Officer: O4 and above (Major and above).
      P < .05, based on χ2 test.
      Junior Enlisted90 (31)65 (72)38 (42)23 (26)47 (52)40 (44)35 (39)
      Senior Enlisted84 (29)60 (71)37 (44)15 (18)41 (49)29 (35)42 (50)
      Junior Officer82 (28)62 (76)40 (49)23 (28)49 (60)26 (32)30 (37)
      Senior Officer33 (11)29 (88)22 (67)12 (36)12 (36)6 (18)16 (48)
      Strength training (weekly)
      P < .01, based on χ2 test.
      P < .01, based on χ2 test.
      P < .05, based on χ2 test.
      P < .01, based on χ2 test.
      P < .01, based on χ2 test.
      No33 (11)15 (45)6 (18)3 (9)3 (9)4 (12)10 (30)
      Yes256 (89)201 (79)131 (51)70 (27)146 (57)97 (38)113 (44)
      Aerobic exercise, min (weekly)
      P < .01, based on χ2 test.
      P < .05, based on χ2 test.
      P < .05, based on χ2 test.
      ≤601 (0)0 (0)0 (0)0 (0)0 (0)0 (0)0 (0)
      61-31448 (17)33 (69)22 (46)12 (25)17 (35)14 (29)17 (35)
      315-46465 (22)40 (62)25 (38)13 (20)29 (45)15 (23)21 (32)
      ≥465175 (61)143 (82)90 (51)48 (27)103 (59)72 (41)85 (49)
      a DS = dietary supplement.
      b MV/MM = multivitamin/multimineral.
      c IV/M = individual vitamin and/or mineral.
      d P/AA = protein/amino acid supplement.
      e Junior Enlisted: E1-E4 (Private, Private Second Class, Private First Class, Specialist); Senior Enlisted: E5-E7 (Sergeant, Staff Sergeant, Sergeant First Class); Junior Officer: O1-O3 (Second Lieutenant, First Lieutenant, Captain); Senior Officer: O4 and above (Major and above).
      P < .05, based on χ2 test.
      ∗∗ P < .01, based on χ2 test.
      Overall, 92% of participants reported being in excellent to good health, 64% reported excellent to good eating habits, 43% were trying to lose weight, and 83% scored above 240 points in the Army Physical Fitness Test (180-point passing score; 300-point maximum score) (Table 2). Three-fourths of study participants used some type of DS at least once per week during the 12 months before the study. The predominant DSs consumed were protein and amino acid products (52%) (Figure 1). Users of DSs spent a mean ± SD of approximately $76.77 ± $56.77 per month on supplements in the prior 3 months. Seven percent of the participants incorrectly believed the US government requires all DSs sold to work as advertised, and 34% incorrectly believed the US government verifies the safety of DSs. Approximately one-third (38%) of participants were extremely to very confident that DS claims of manufacturers were accurate (Table 2). The top 5 locations from which DSs were purchased were on-post brand name supplement franchise store (44%), off-post brand name supplement store (21%), other supplement store (21%), military general retail or exchange store (18%), grocery stores (11%) and DS online store (10%).
      Table 2Questionnaire responses on eating habits, fitness, and dietary supplement knowledge and opinions by US Army personnel (n = 289) participating in a mixed-methods study examining decision-making and factors associated with dietary supplement use
      QuestionResponse selectionn (%)
      Rating of overall healthExcellent89 (31)
      Good177 (61)
      Fair23 (8)
      Poor0 (0)
      Rating of overall eating habitsExcellent24 (8)
      Good162 (56)
      Fair79 (27)
      Poor24 (8)
      Body weight goalsTrying to lose weight123 (43)
      Trying to gain weight32 (11)
      Maintaining weight100 (35)
      Not doing anything34 (12)
      Ever enrolled in the Army Weight Control Program
      Army Weight Control Program (US Army
      Army Regulation 600-9: The Army Body Composition Program.
      Yes29 (10)
      No257 (89)
      Not sure3 (1)
      Army Physical Fitness Test score
      Army Physical Fitness Score (earlier version), consisted of 3 events push-ups, sit-ups, and 2-mile run. Minimum passing score is 60 points for each event.46
      ≥30040 (14)
      290-29952 (18)
      240-289148 (51)
      180-23940 (14)
      <180 or not sure9 (3)
      Awareness of ingredients contained in DS
      DS = dietary supplement.
      Never taken DS36 (13)
      Not used DS in 12 mo34 (12)
      Very good awareness52 (18)
      Good awareness119 (41)
      Poor awareness42 (15)
      Very poor awareness4 (1)
      Belief US Government requires DS to work as advertisedNot sure74 (26)
      Yes21 (7)
      No194 (67)
      Belief US Government requires DS sold to be safeNot sure55 (19)
      Yes97 (34)
      No137 (47)
      Confidence DS will do as claimedNot taken DS in 12 mo30 (11)
      Extremely confident25 (9)
      Very confident85 (30)
      Somewhat confident110 (38)
      Not confident at all8 (3)
      Confidence current DS taken is safe to consumeNever taken a DS29 (10)
      Not taken in 12 mo30 (11)
      Extremely confident36 (13)
      Very confident100 (35)
      Somewhat confident81 (28)
      Not confident at all11 (4)
      a Army Physical Fitness Score (earlier version), consisted of 3 events push-ups, sit-ups, and 2-mile run. Minimum passing score is 60 points for each event.

      Headquarters, Department of the Army, Army Physical Readiness Training (Field Manual 7-22, Appendix A, Published October 2012. Accessed October 6, 2020, https://www.up.edu/armyrotc/files/reading-material/fm-7-22-appendix-a-apft.pdf.

      b DS = dietary supplement.
      Figure thumbnail gr1
      Figure 1Self-reported dietary supplement use at least once per week during the past year by US Army personnel (n = 289) participating in a mixed-methods study to explore underlying factors of use.

      Results From the Focus Groups

      Results from 14 focus-group session transcripts (n = 129) are organized into major themes and described with supporting quotes from study participants (Figure 2).
      Figure thumbnail gr2
      Figure 2Major themes reported during focus-group sessions for reasons and benefits of dietary supplement use by US Army personnel (n = 129) participating in a mixed-methods study to understand underlying factors for dietary supplement (DS) use.

      Reasons and Benefits of DS Use

      The most frequent reasons stated for use of DSs were to improve physical appearance or physique; increase lean muscle mass; maintain or optimize general health; reduce body weight or fat for personal reasons; or to meet Army standards for body weight and body composition, physical fitness, and military appearance. Noncompliance with the standards can impact future career advancement opportunities. In addition, DS use was viewed as a source of energy, motivation to exercise, improve focus, reduce pain in joints, reduce muscle soreness, prevent age-related health decline, and as a response to peer influence. The DS users said they “stack” use of multiple DSs for additive effects and to prevent adverse effects. Among nonusers, factors cited for nonuse of DSs included safety concerns, awareness of adverse effects in others, limited knowledge of DSs, and a preference for “natural” methods for achieving desired benefits. In addition, some previous users of DSs said they stopped using them after experiencing pain due to intense workout levels and overexertion during exercise, which they attributed to use of DSs. Others ceased using DSs because they did not experience the expected benefits. Some DS users stated they stop and restart DS use as part of a “cycle” regimen to avoid a decline in perceived physical effects of DSs over time. Quotes of responses to illustrate this theme are provided in Figure 3A .
      Figure 3Selected quotes from focus-group sessions (14 sessions) relating to various themes with reasons and factors motiving use of dietary supplements by US Army Personnel (n = 129) participating in a mixed-methods study examining decision-making and factors associated with use. (A) Quotes from theme regarding reasons and benefits of DS use. (B) Quotes from theme regarding DS decision-making and information sources. (C) Quotes from theme regarding confidence in DS safety and efficacy. (D) Quotes from theme regarding cost, access, and time involvement. (E) Quotes from theme regarding short-term safety concerns. (F) Quotes from theme regarding long-term safety risks. (G) Quotes from theme regarding deployments. (H) Quotes from theme DS guidance and education
      (A)
      Participant InformationQuote
      Male, Sergeant (Senior Enlisted)“I mean, mine is more a less, just to maintain my body where it was before I got older, because when you get older you tend to lose a lot of what you had when you was a young guy or a young girl . . . Because as we all know in the Army you have to maintain a certain weight, you have to maintain a certain look and if you don’t have that you lose your job.
      Male, Captain (Junior Officer)“I’ll sometimes take my pre-workout just to force myself to go the gym like if I’m in that zone where I am thinking about going to the gym, but I don’t really feel like it, I’ll take a pre-workout and be like all right well there’s no turning back now.”
      Female, Sergeant (Senior Enlisted)“I think mine is more so appearance. I don’t like my nails breaking, or I want like longer hair even though I chopped it off, longer hair longer nails, just to maintain the weight I am at and also um I have been considering taking a protein powder because we skip meals. I’m overworked and we skip meals so I am hungry or I wake up hungry sometimes.”
      Male, Major (Senior Officer)“I think improving, uh, physical appearance more than overall health for me.”
      (B)
      Participant InformationQuote
      Male, Captain (Junior Officer)“I remember seeing an article about two Soldiers dying from a pre-workout . . . and the next day I continued taking it. I had been taking it previously and been fine, so I thought I am going to just keep taking it.”
      Female, Sergeant (Senior Enlisted)“I take this pre-workout and pass the finish line and your heart’s about to bust it’s not the same, it’s not the same. A lot of it is Army, a lot of it is peers, a lot of it is being pure lazy I don’t wanna do the work that it takes to workout. I don’t wanna put in, I don’t have the money to spend, I don’t wanna spend the money on some special foods and organic this. I want quick fast bikini body now put that on the board, what they say gets me there and 6 months down the road I’ll be in the hospital. But I was lookin good for this one period of time . . . I got my pictures on [social media] and you know what? That’s all I need for society to see me . . . but behind closed doors my body is deteriorating inside out.”
      (C)
      Participant InformationQuote
      Male, First Lieutenant (Junior Office)“I think it’s in how the individual uses it. They have guidelines on how the supplement should be taken, and I think if you don’t do your own individual research you could very well misuse that supplement as well. It’s all about the individual.”
      Male, Major (Senior Officer)“I think supplements work, there may be some health issues with it, but the biggest problem is the overuse or like I said before the synergistic effects of not knowing what supplement counteracts or works with it or works against the other.”
      Male, Staff Sergeant (Senior Enlisted)“I look at it as almost a return on investment.”
      (D)
      Participant InformationQuote
      Male, First Lieutenant (Senior Officer)“If I’m a Special Forces guy, I would much rather take pre-workout all day . . . to increase my chances of living 5 years from now as opposed to worrying about what’s going to happen 20 years from now.”
      Male, Specialist (Junior Enlisted)“Like once every month, you usually get a 30-day supply of something, and it’s like say you get a multivitamin that’s $60, you get a cutter [a product to lose body fat, weight and/or water], that’s $60, $50, then you might get a fish oil, that’s like $30, $40—almost $200 right there and you’re doing it once a month, so….”
      Male, Major (Senior Officer)“All this soldier wanted was a can of protein and some pre-workout and he sold him $300 worth of crap, because the soldier has no experience and he got so. It is like you go to the dealership to buy a car and you are thinking $20,000 and by the time you leave you spend $40,000 on a car. Because you get wrapped up in the moment.”
      Male, Major (Senior Officer)“[DS name brand store] is in the PX [post exchange/retail store]. I don’t care what anyone says, people are going to see that as affiliated with the military, right?”
      (E)
      Participant InformationQuote
      Male, Staff Sergeant (Senior Enlisted)“It’s a leap of faith, me personally, I don’t think anybody that takes supplements will truly know the effects for years to come. You mitigate your risk by following the instructions, drinking water, but everybody knows that anytime you put something in your body you take a risk . . . I know that I think it’s not going to kill me right now, but in 20 or 30 years from now my liver might stop. It is a risk you take, and it is a risk you are willing to take.”
      Male, First Lieutenant (Junior Officer)“The niacin. Burns. Your skin, face burns. Everything burns. It feels like your 130 degrees and cold. I take 3 scoops and it feels like your skin is on fire and the only way to get rid of the feeling is to lift which then intensifies how you’re already feeling and your face is like a cherry, it’s a terrible experience.”
      (F)
      Participant InformationQuote
      Male, Specialist (Junior Enlisted)“I wonder sometimes because I end up taking like 12 pills a day and I sit there and think that I don’t know if it’s safe, but nothing bad has happened so far so I might be good.”
      Male, Staff Sergeant (Senior Enlisted)“I definitely think there’s . . . a short term gain, long term loss. We are all on a limited, limited timeframe. . . . We all have a certain shelf life depending on what job you have . . . wherever your job is, it is going to destroy your body. What you have to say is, if I can get myself strong for the first ten years of my career so I can make Staff Sergeant . . . I’ll do that for a portion of my career then as I transition to leadership . . . Then when you get through portions of your career you are able to say, 'O.K. I got through Air Assault School, trained up for it and I used supplements at that time. I got through Airborne School because I had supplements for that and I built up my resistance.' . . . I mean we are all gonna be broken in the next twenty-five years. Nobody at this table has any delusions. When we are 48-49 years old we aren’t gonna be running around with our grandkids . . . I realize that for myself anyways."
      Male, Sergeant (Senior Enlisted)“I think what concerns me the most is the whole safety aspect of it and that it’s a lightly regulated market. It may or may not work like it’s supposed to, and there’s not an awful lot of tests that happen. And what happens if I take these two things at the same time, what exactly is it going to do to my body? It scares me.”
      (G)
      Participant InformationQuote
      Male, Specialist (Junior Enlisted)“That’s when I first really got into it was in Afghanistan because I prided myself on like being natural, not doing it, when I was over there it’s like everybody was doing it so I was like might as well try it out since I’m over here and I’m in the gym 24/7, why not.”
      Male, Specialist (Junior Enlisted)“Alpha male type environments. You gotta be the biggest, the baddest, the strongest, fastest. Always, always, always."
      Male, First Lieutenant (Junior Officer)“Interactions, seeing some of the other guys, it seems like a lot of it is just going on a whim especially in a deployed environment where you don’t really have a lot else going on and you walk into a guy’s room and there’s a ton of supplements and you’re like “What are you doing? How do you even take all of these during the day and also eat?”
      (H)
      Participant InformationQuote
      Male, Major (Senior Officer)“It would be nice to brief something that actually benefits soldiers instead of “don’t do this because it’s dangerous”
      Male, Major (Senior Officer)“I think it’s important we focus on comprehensive fitness . . . The Army is a physical endeavor, at the end we exist so we put infantryman on the ground to go do those physical things, so I think we have to think about it as the whole health. DFAC [dining facility], what you eat, the things you put in your body, medical tests that you get, all that has to be inclusive. So I think we have to take that tack instead of the tack that I fear . . . 'Were really worried about [brand name pre-workout dietary supplement], so here is a slide why it’s bad,' because that’s the wrong way to do it. “

      Decision-Making and Information Sources

      Participants noted a variety of information sources influenced their choice of DSs. Those sources included internet searches; online reviews; fitness forums, blogs, or magazines; conversations with others; personal experience; and simple trial and error. Store or brand marketing information influenced the decision-making process for DS selection. Decision-making priorities and practices changed with age; experience with DS use and senior military personnel were more concerned with long-term, negative health effects. Study participants reported receiving information from Army channels after an adverse event related to DS use. Quoted responses illustrating this theme are provided in Figure 3B.

      Confidence in DS Use Benefits and Safety

      Participants stated they believed successful DS use requires “finding what works for you” and that “everyone is different.” Seemingly direct, observable benefits of DS use in themselves or others contributed to some level of confidence a DS would work as claimed. Most participants believed safe and effective DS use required some degree of personal responsibility, such as personal research and adherence to manufacturer instructions. Some participants believed DSs to be safer than over-the-counter medications (ie, safety warnings typically accompany medications, not DSs), others were skeptical about DS claims and safety due to lack of FDA regulations. Some participants were concerned with preworkout DS safety after experiencing undesirable adverse events. Many admitted safety-issue fears and avoiding new products until they had been on the market for some time. Some soldiers demonstrated lack of knowledge, as they mentioned they feel more confident about DS safety because the FDA approved labels on the packaging. Quoted responses to illustrate this theme are provided in Figure 3C.

      Cost, Access, and Time Involvement Issues

      DS users expressed that the cost of DSs are high but perceived value in the price. Users of DSs viewed it as an investment in themselves and their career. Many users tend to increase use over time, try new DSs, and become more invested or engaged in DS-related behaviors. Participants reported access to DSs on military installations creates a perception of safety and official Department of Defense approval for their use. Quoted responses illustrating this theme are provided in Figure 3D.

      Short-Term Safety Concerns

      Participants frequently stated the individual, rather than the product itself, was at fault when safety or serious adverse-effect issues occurred. This was attributed to excessive use or not following instructions, such as adhering to appropriate hydration levels. Study participants also indicated they felt cases of severe adverse DS effects among soldiers were exceptions and could be due to underlying individual medical issues or product misuse. Quoted responses to illustrate this theme are provided in Figure 3E. Individual adverse effects experienced by some focus-group participants were increased heart rate; tingling on face, skin, and arms; and itching near the nose. Some participants were aware kidney and liver failure were potential side effects of DS use.

      Long-Term Safety Risks

      Participants generally felt uncertain about the long-term health effects of DSs. Some did not use or stopped using DSs due to long-term health concerns, and others saw them as a long-term health benefit and viewed DS use as a method to prevent a decline in fitness and health due to aging. Some acknowledged there are health risks to DS use; however, they accepted these risks so they could continue receiving the perceived benefits of them. Many viewed risks as minor issues in a broader context relative to the greater hazards inherent to being a soldier. Quoted responses illustrating this theme are provided in Figure 3F.

      Deployments

      Participants reported that deploying with their military unit away from home was often the first time they used DSs, or that deployment promoted an increased level of DS use. Gym culture, increased exposure to peers using DSs, increased leisure time, special or incentive pay, limited spending options, security threats, and ability to order online were reported as reasons for increased use of DSs during deployments. Additional reasons cited for increased DS use during deployment was achievement of fitness goals, to return in better shape or physique, to improve job performance, and to benefit their personal advancement. Quoted responses to illustrate this theme are provided in Figure 3G.

      DS Guidance and Education

      Current guidance for DS use provided by the military chain of command mainly concerned reaction to specific adverse event cases, emphasis on banned DSs, or those DSs that may result in positive drug urine analysis tests because regular testing is conducted on all soldiers. Participants expressed the need for the Army to provide some type of DS-related education. However, opinions varied regarding the type of training and delivery method desired. Many stated DS education should be incorporated into existing programs. Some said there was a need for training on overall nutrition and fitness, and others felt mandatory training is necessary to educate soldiers who would not otherwise seek DS information. Another viewpoint was that training would not be effective and would just be an additional time burden. Some lacked trusted resources and availability of knowledgeable personnel who could provide guidance on DSs. Quoted responses to illustrate this theme are provided in Figure 3H.

      Discussion

      This study found 75% of soldiers used some type of DS at least once per week, the most popular being protein and amino acid supplements, and users spend on average $76.77 per month on these products, much more than comparable civilian populations.
      US sales of vitamins and nutritional supplements manufacturing 2018-2019. Statista.
      Studies of soldiers using a nearly identical survey conducted several years ago, reported that DS use was somewhat lower (64%); monthly spending was somewhat higher; and multivitamins, not protein and amino acids, were the most popular DSs.
      • Lieberman H.R.
      • Stavinoha T.B.
      • McGraw S.M.
      • White A.
      • Hadden L.S.
      • Marriott B.P.
      Use of dietary supplements among active-duty US Army soldiers.
      ,
      • Austin K.G.
      • McLellan T.M.
      • Farina E.K.
      • McGraw S.M.
      • Lieberman H.R.
      Soldier use of dietary supplements, including protein and body building supplements, in a combat zone is different than use in garrison.
      ,
      • Austin K.G.
      • Price L.L.
      • McGraw S.M.
      • McLellan T.M.
      • Lieberman H.R.
      Longitudinal trends in use of dietary supplements by U.S. Army personnel differ from those of civilians.
      The majority of soldiers were aware of the government’s limited role in regulating DS efficacy and safety, but many nonetheless incorrectly believed the US government required all DSs sold to work as advertised, and one-third of participants incorrectly believed the US government verified the safety of DSs. A substantial number of soldiers believed supplements could improve their health, physical appearance, career opportunities, and performance; however, they were uncertain about how these benefits would occur.
      There were many new observations that resulted from use of the qualitative focus-group method as unlike standardized surveys, focus groups provide participants structured qualitative opportunities to express themselves. Many soldiers understood there was a possibility of adverse events occurring through use of DSs, but they believed the risks were minimal compared with those associated with serving in a combat arms profession. Concerns about potential short-term health risks associated with DSs often were inconsistent with beliefs that supplements could prevent longer-term declines in fitness and health. Respondents acknowledged they lacked access to education on DSs and nutrition, but were receptive to improving their knowledge as long as the information was provided by trusted health care experts who possess expertise in fitness and nutrition, such as Army registered dietitian nutritionists. They suggested education on DSs and nutrition be provided early in soldiers’ careers because many did not use DSs before joining the military, and started or increased use due to deployment.
      Routine use of DSs has been observed previously in 64% of Army soldiers, 68% of Air Force, 70% of Coast Guard, and 73% of Navy/Marine uniformed personnel.
      • Austin K.G.
      • Price L.L.
      • McGraw S.M.
      • Lieberman H.R.
      Predictors of dietary supplement use by U.S. Coast Guard personnel.
      ,
      • Austin K.G.
      • Price L.L.
      • McGraw S.M.
      • McLellan T.M.
      • Lieberman H.R.
      Longitudinal trends in use of dietary supplements by U.S. Army personnel differ from those of civilians.
      ,
      • Knapik J.J.
      • Trone D.W.
      • Austin K.G.
      • Steelman R.A.
      • Farina E.K.
      • Lieberman H.R.
      Prevalence, adverse events, and factors associated with dietary supplement and nutritional supplement use by US Navy and Marine Corps personnel.
      ,
      • Austin K.G.
      • Price L.L.
      • McGraw S.M.
      • et al.
      Demographic, Lifestyle factors, and reasons for use of dietary supplements by Air Force personnel.
      It is clear DS use is widespread in military personnel, similar in prevalence, and these similar populations use similar DSs for similar reasons, in particular physical performance enhancement. The qualitative, focus-group findings of this study demonstrate soldiers report they primarily use DSs for enhancement of physical performance, appearance, and health. Also, DSs were sometimes viewed as a way to increase motivation to exercise.
      Unlike soldiers, in the US adult civilian population overall prevalence of DS use is lower, about 50%, and civilians are much less likely than military populations to use DSs such as protein and amino acid supplements for performance enhancement.
      • Bailey R.L.
      • Gahche J.J.
      • Lentino C.V.
      • et al.
      Dietary supplement use in the United States, 2003-2006.
      ,
      • Dickinson A.
      • Blatman J.
      • El-Dash N.
      • Franco J.C.
      Consumer usage and reasons for using dietary supplements: Report of a series of surveys.
      These differences are due in part to differences in demographic factors, such as sex and age.
      • Lee H.Y.S.H.
      • Short S.D.
      Consumption of vitamins and associated factors by age group.
      However, they are clearly related to the unique occupational demands of military service, as suggested by the literature and verified by the focus-group data collected in this study. Although studies of the general population demonstrate clear preference for DSs that could potentially be used to improve general health, there are other civilian subpopulations that use DSs in a manner that is similar to soldiers. For example, athletes are heavy users of DSs for performance enhancement (for a recent meta-analysis see Knapik and colleagues
      • Knapik J.J.
      • Steelman R.A.
      • Hoedebecke S.S.
      • Austin K.G.
      • Farina E.K.
      • Lieberman H.R.
      Prevalence of dietary supplement use by athletes: Systematic review and meta-analysis.
      ). In addition, college students use more DSs for purported performance and energy enhancement than the general civilian population.
      • Lieberman H.R.
      • Marriott B.P.
      • Williams C.
      • et al.
      Patterns of dietary supplement use among college students.
      Soldiers reported using DSs to increase muscle strength, workout energy, motivation, mental focus, and to alleviate pain, and to prevent age-related health declines. Most US adults use DSs to optimize overall health.
      US sales of vitamins and nutritional supplements manufacturing 2018-2019. Statista.
      ,
      • Bailey R.L.
      • Gahche J.J.
      • Miller P.E.
      • Thomas P.R.
      • Dwyer J.T.
      Why US adults use dietary supplements.
      The focus-group findings of this study demonstrate the lack of clear guidance to soldiers regarding DS safety and ways to achieve performance and fitness goals, although an official Department of Defense website provides such information (Operation Supplement Safety; https://www.opss.org/). Soldiers seek guidance from numerous sources and consider DS use as an investment to succeed in their careers. A focus-group study that examined factors motivating use of energy drinks found soldiers willing to take risks to achieve desired performance and health benefits, and that there was a lack of effective training on evidence-based strategies.
      • Bukhari A.S.
      • Caldwell J.A.
      • DiChiara A.J.
      • et al.
      Caffeine, energy beverage consumption, fitness, and sleep in U.S. Army Aviation personnel.
      The widespread availability of DSs in stores located on military installations appears to have created easy access, the perception of safety, and implicit approval for use of DSs by military leadership. Because legal authority for regulation of DSs is the responsibility of the FDA, and such regulation by law is minimal, the Department of Defense’s authority is also limited.
      The present investigation demonstrates DSs are widely used by Army personnel in an effort to safeguard or improve health as well as to benefit energy and performance. However, military personnel often take supplements based on undocumented beliefs the DSs used are proven to be safe and effective.
      • Austin S.B.
      • Yu K.
      • Liu S.H.
      • Dong F.
      • Tefft N.
      Household expenditures on dietary supplements sold for weight loss, muscle building, and sexual function: Disproportionate burden by gender and income.
      These findings demonstrate it is essential to provide personnel with evidence-based facts in a manner that is acceptable and easily accessible, which the soldiers in this investigation consistently were interested in receiving.
      This study had limitations. The sample size was relatively small, as this is the only practical way to conduct a focus-group study, and although a high degree of homogeneity exists in military populations, it is possible the results are not representative of the Army. However, a number of prior surveys have yielded results that are consistent with those of this study.
      • Austin K.G.
      • Price L.L.
      • McGraw S.M.
      • Lieberman H.R.
      Predictors of dietary supplement use by U.S. Coast Guard personnel.
      ,
      • Austin K.G.
      • Price L.L.
      • McGraw S.M.
      • McLellan T.M.
      • Lieberman H.R.
      Longitudinal trends in use of dietary supplements by U.S. Army personnel differ from those of civilians.
      ,
      • Knapik J.J.
      • Trone D.W.
      • Austin K.G.
      • Steelman R.A.
      • Farina E.K.
      • Lieberman H.R.
      Prevalence, adverse events, and factors associated with dietary supplement and nutritional supplement use by US Navy and Marine Corps personnel.
      ,
      • Austin K.G.
      • Price L.L.
      • McGraw S.M.
      • et al.
      Demographic, Lifestyle factors, and reasons for use of dietary supplements by Air Force personnel.
      It should also be noted that focus-group methodology is susceptible to biases associated with potential conformity among group members, desirability of participants to please the group moderator, and/or influences associated with lack of anonymity. Considerable efforts were made to minimize these issues by composing focus groups to reduce inhibitions based on factors such as rank; to mitigate the possibility of rank intimidation; by ensuring anonymity of participants to those outside of their group; and providing a well-trained, nonjudgmental moderator to attenuate response inhibition, but it was not possible to disguise sex, age, and race. Furthermore, the use of different facilitators could have resulted in inconsistent emphasis on the standardized themes. However, to mitigate this possibility, all facilitators rehearsed together before conducting group sessions to maximize consistency in probing questions and to minimize focusing on particular themes.

      Conclusions

      The current study confirms high use of DSs among soldiers who are motivated by fitness goals and occupational demands. Soldiers who use DSs spend, on average, more than $75 per month on DSs, yet typically lack information on DS safety and efficacy. By using focus groups in the context of a mixed-method design, this research extends previous findings by providing in-depth knowledge of the reasons soldiers choose to use DSs, which includes the desire to enhance physical performance, appearance, and overall health; lack of nutritional options; peer opinions; ease of accessibility; perception of low risk compared with occupational risks; and deployment. Soldiers consistently expressed a need for access to trusted health care professionals to provide guidance on DS use, especially early in their careers and before deployment, as both lead to use of DSs. Although best practice is to promote a food-first approach to achieving optimal nutrition, this is clearly not realistic, given the reasons soldiers say they use DSs and the very high proportion that use them. Therefore, there is a need for research to determine optimal strategies for providing guidance by military registered dietitian nutritionists and other health care professionals on safe use of DSs. Training on safe use of DSs should be provided by using the Army chain of command, as soldiers expect their leaders to provide guidance. Also, research should be conducted in other military populations and similar civilian populations to validate and extend the findings of this study and assess the impact of risky DS use on soldier and civilian health and performance.

      Acknowledgements

      The authors wish to acknowledge CPT John J. Sepowitz, MS, RDN, CSSD, Daniel A. Harshman and his team, Installation G3, and the Soldiers from the 3 installations for their considerable help with this study. The views expressed in this paper are those of the authors and do not reflect the official policy of the Department of Army, Navy, Air Force, Department of Defense, or US Government. Any citations 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. Permission has been received from those named in this acknowledgement.

      Author Contributions

      A. S. Bukhari, A. J. DiChiara, E. P. Merrill, A. O. Wright, S. M. McGraw, S. J. Montain, and H. R. Lieberman contributed to the study design, A. S. Bukhari, A. J. DiChiara, E. P. Merrill, A. O. Wright, S. M. McGraw, R. E. Cole, and A. Hatch-McChesney collected the data. A. S. Bukhari and A. J. DiChiara wrote the first draft with contributions from E. P. Merrill, A. O. Wright, R. E. Cole, A. Hatch-McChesney, S. J. Montain, J. A. Caldwell, L. A. Thompson, H. R. Lieberman. All authors reviewed and commented on subsequent drafts of the manuscript.

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      Biography

      A. S. Bukhari is a senior researcher, Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA.
      A. J. DiChiara is a research psychologist, US Army Combat Capabilities Development Command Soldier Center, Natick, MA.
      E. P. Merrill is a research psychologist, US Army Combat Capabilities Development Command Soldier Center, Natick, MA.
      A. O. Wright is a nutrition analysis laboratory manager and food technologist, US Army Combat Capabilities Development Command Soldier Center, Natick, MA.
      R. E. Cole is a director, US Military, Baylor University Graduate Program in Nutrition, Medical Center of Excellence, Joint Base San Antonio, Fort Sam Houston, TX.
      A. Hatch-McChesney is a registered dietitian, Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA.
      S. M. McGraw is a nutrition researcher, Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA.
      J. A. Caldwell is a research physiologist, Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA.
      S. J. Montain is a chief, biophysics and biomedical monitoring division, US Army Research Institute of Environmental Medicine, Natick, MA.
      L. A. Thompson is a research biologist, Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA.
      H. R. Lieberman is a research psychologist, Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA.