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The Journal of Nutrition
Supplement: Efficacy and Safety of Protein Supplement Use
by Military and Other Physically Active Populations
Protein Supplementation in U.S. Military Personnel
1–4
Stefan M. Pasi akos,* Scott J. Montain, and Andrew J. Young
Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA
Abstract
Protein supplements (PSs) are, after multivitamins, the most frequently consumed dietary supplement by U.S. military
personnel. Warfighters believe that PSs will improve health, promote muscle strength, and enhance physical
performance. The estimated prevalence of regular PS use by military personnel is nearly 20% or more in active-duty
personnel, which is comparable to collegiate athletes and recreationally active adults, but higher than that for average U.S.
civilians. Although the acute metabolic effects of PS ingestion are well described, little is known regarding the benefits of
PS use by warfighters in response to the metabolic demands of military operations. When dietary protein intake approaches
1.5 g kg
21
d
21
, and energy intake m atches energy expenditure, the use of PSs by most physically active military personnel
may not be necessary. However, dismounted infantry often perform operations consisting of long periods of strenuous
physical activity coupled with inadequate dietary energy and protein intake. In these situations, the use of PSs may have
efficacy for preserving fat-free mass. This article reviews the available literature regarding the prevalence of PS use among
military personnel. Furthermore, it highlights the unique metabolic stressors affecting U.S. military personnel and discusses
potential conditions during which protein supplementation might be beneficial. J. Nutr. 143: 1815S–1819S, 2013.
Introduction
The dietary supplement (DS)
5
industry continues to grow rapidly,
with sales in the United States now exceeding $30 billion annu-
ally (1). The U.S. military population regularly uses large
amounts of DSs (2–6). Recent evidence suggests that more than
half of the active-duty U.S. Army population regularly consumes
DSs (3). Protein supplements (PSs) are, after multivitamins, the
most popular DS consumed. Despite the high rate of PS use in
warfighters
6
, data addressing the efficacy and safety of consum-
ing supplemental protein are sparse.
Physically active individuals, such as athletes, appear to benefit
from consuming dietary protein in excess of the RDA (7–9). In
certain military occupations, such as infantry, the strenuous nature
of the occupational duties may produce dietary energy and protein
requirements similar to resistance- and endurance-trained athletes.
Equally important, members of these occupations are often in
logistically and time-constrained situations that contribute to
undereating relative to energy expenditure and desired amounts of
dietary protein (10). However, the vast majority of military
occupations are less physically demanding than occupations such
as the infantry, and their protein needs are likely met by normal
dietary intake. This diversity of physiological demand within the
military requires consideration when assessing efficacy and safety
of PS use by warfighters. In addition, the potential for PSs to
impose unintentional metabolic harm must be considered, given
that concerns have been raised that too much dietary protein
might initiate or promote renal dysfunction (11,12), and because
DSs could be contaminated (13).
This concise review summarizes what is known regarding PS
use among military personnel. It also introduces the reader to the
6
The term ‘‘warfighter’’ is used by the U.S. Department of Defense to refer to any
member of the U.S. Armed Forces. Warfighter is intended to be neutral regarding
military service or branch, sex, and service status and replaces previously used
terminology including ‘‘soldier,’’ service member,‘‘ and ’’military personnel.’’
1
Presented at the Efficacy and Safety of Protein Supplements for U.S. Armed
Forces Personnel meeting, held at the U.S. Army Research Institute of
Environmental Medicine, Natick, MA, 7–8 November 2012. The summit was
sponsored by the Department of Defense, Center Alliance for Dietary
Supplements Research. The views expressed in these papers are not neces-
sarily those of the Supplement Coordinator or Guest Editors. The Supplement
Coordinator for this supplement was Krista G. Austin, U.S. Army Research
Institute of Environmenta l Medicine. Supplement Coordinator disclosures: Krista
G. Austin had no conflicts to disclose. This supplement is the responsibility of the
Guest Editor to whom the Editor of The Journal of Nutrition has delegated
supervision of both technical conformity to the published regulations of The
Journal of Nutrition and general oversight of the scientific merit of each article.
The Guest Editor for this supplement was Kevin Schalinske. Guest Editor
disclosure: Kevin Schalinske had no conflicts to disclose. Publication costs for
this supplement were defrayed in part by the payment of page charges. This
publication must therefore be hereby marked "advertisement" in accordance with
18 USC section 1734 solely to indicate this fact. The opinions expressed in this
publication are those of the authors and are not attributable to the sponsors or
the publisher, Editor, or Editorial Board of The Journal of Nutrition.
2
Supported by the U.S. Army Military Research and Material Command and the
Department of Defense Center Alliance for Dietary Supplement Research.
3
Authors disclosures: S. M. Pasiakos, S. J. Montain, and A. J. Young, no
conflicts of interest.
4
The opinions or assertions contained herein are the private views of the authors
and are not to be construed as official or as reflecting the views of the Army or
the Department of Defense. Any citations of commercial organizations and trade
names in this report do not constitute an official Department of the Army
endorsement of approval of the products or services of these organizations.
* To whom correspondence should be addressed. E-mail: stefan.pasiakos@us.
army.mil.
5
Abbreviations used: AA, amino acid; DS, dietary supplement; FFM, fat-free
mass; PS, protein supplement; SF, special forces.
ã 2013 American Society for Nutrition.
Manuscript received February 19, 2013. Initial review completed April 25, 2013. Revision accepted May 3, 2013.
1815S
First published online September 11, 2013; doi:10.3945/jn.113.175968.
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varied metabolic demands of military occupations and the
challenges (or lack thereof) of service members meeting their
nutritional needs by diet alone. The intent is to facilitate informed
discussion with regard to the merits and risks of PS use by military
personnel.
Prevalence and Rationale of PS Use among
Warfighters
The U.S. Department of Defense, the Samueli Institute, and the
NIH, with additional support from the Food and Drug Adminis-
tration, requested that the Institute of Medicine convene an ad hoc
committee to assess DS use by military personnel and recom-
mended an approach to determine which DSs need to be actively
managed (14). An examination of the available scientific evidence
revealed widespread use of DSs, particularly PSs. For example, DS
use among 2215 U.S. Army Special Forces (SF) and U.S. Army
Ranger trainees between 1997 and 1998 was nearly 65%, with
most indicating using $1 DS daily (6). Nearly 30% of the special
operations candidates surveyed were consuming some form of
amino acid (AA) or protein-type mixture, and 14% were using
PSs daily. The prevalence of PS use was more common among
trainees performing resistance- and endurance-type exercise $ 3
times per week. Bovill et al. (2) confirmed these findings, because
the rate of PS use among SF soldiers (25%) was also predicted by
exercise frequency. Special operations soldiers believed that
consuming PSs would enhance physical performance by providing
energy. This decision was based on nutrition information obtain ed
mainly from magazines, friends, and teammates and not scientific
evidence. The pervasive use of PSs in this population of warfighters,
which has been reported to be as high as 63% (15), is not surprising
considering the occupational and physical demands of special
operations.
Surveys of PS use by U.S. military personnel have provided
varied outcomes. Brasfield (16) assess ed DS use among 874 active-
duty U.S. Army soldiers across 16 army installations located
within the continental US, and found that only 5% of the population
reported using AA supplements. However, t hose who reported using
AA supplements were doing so >5 times per week. In contrast, 43%
of U.S. Marine Corps recruits entering basic training in 2007
indicated using PSs regularly, and PSs were the most popular
DS surveyed in this population (5). Data from >105,000 U.S.
military personnel in the Millennium Cohort Study further
support a high rate of PS use: 23% of men and 5% of women
reported regular consumption of bodybuilding supplements. The
prevalence was highest in warfighters with $1 of the following
characteristics: U.S. Marines, healthy weight, active duty, married
(for men), deployed, or combat specialist and individuals that
participate in routine resistance- and endurance-type training (4).
The most comprehensive and detailed assessment of DS use
among active-duty military personnel to date was conducted by
Lieberman et al. (3), who randomly administered surveys to 990
soldiers across 11 global U.S. Army installations from 2006 to
2007. The use of DSs for the 6 mo before survey administration
was queried, and the data were weighted by age, sex, rank, and
SF status so as to represent the active-duty U.S. Army. More than
50% reported consuming DSs at least once per week. Multivi-
tamins and multiminerals were the most common (38%) DS
consumed. PSs were the second most popular DS, with nearly
19% of the population reporting regular use of PSs. The prevalence
of PS use was higher among men (20%) than women (9%), peaked
between the ages of 30–39 y (28%), and was not influenced by
educational status. Rank influenced PS use: a higher percentage of
officers (23%) and senior noncommissioned officers (23%)
reported using PSs compared with warrant o ffic ers (15%) an d
junior enlisted soldiers (14%). Nearly half of the SF soldiers
surveyed indicated regular use of PSs. Similarly, the use of PSs
was higher in s oldiers with military occupations classified as
combat arms (23%) and combat support (20%) than combat
service support (14%). Deployment status did not statistically
influence PS use, although ;26% of soldiers deployed to Iraq
during this time frame indicated using PSs compared with only
19% and 12% of soldiers stationed within and outside the
continental United States, respe ctively. The use of P Ss was
more prevalent in soldiers who frequently participated in resistance-
type training and those who performed nearly 8 h of endurance-
type exercise per week.
The reasons for taking PSs vary. More than half of those
surveyed by Lieberman et al. (3) reported using PSs because they
believe that PSs will create greater muscle strength. Nearly one-
third reported using PSs because they want to enhance physical
performance, whereas 21% consumed PSs to promote general
health. Approximately 10% of soldiers consumed PSs to provide
more energy and increase endurance and because they believe
that PSs will aid with weight loss. More than half were very
confident that the supplements they were consuming were safe
and worked as advertised (17). Similar reasons for using PSs
(combined with bodybuilding supplements) were recently reported
in a large cohort of U.S. military personnel using data derived from
the Department of Defense Survey of Health-Related Behaviors
Among Active-Duty Personnel (18). The most common reasons
for using PSs in this large group of service members (n = 16,146)
were to increase muscle mass (46%), enhance physical perfor-
mance (32%), and improve overall health (22%). Regardless of
the rationale, PS use among U.S. military personnel appears to be
common and may be differentially influenced by varying strenuous
occupational and physical demands of military service.
Comparison of PS Use between
Warfighters and U.S. Civilians
PS use among the general U.S. civilian population is relatively
low. Using random telephone surveys from 1994 to 1995, the
U.S. Food and Drug Administration reported that the use of
AA supplements was as low as 5–9% (19). Data from the third
NHANES (NHANES III, 1988–1994) suggest that PS use was
<2%, although PSs were classified as bodybuilding supplements
and not listed individually (20). Interestingly, using data from
NHANES III and NHANES 2001–2002, Block et al. (21)
reported that 47% of women and 56% of men who were classified
as multiple DS users (i.e., used an average of 17 different DSs per
day) consumed a daily PS. Block et al. (21) reported that multiple
DS users were at lower risk of chronic disease and less likely to
have elevated blood press ure and be diagnosed with diabetes
compared with non-DS users.
Patterns of PS use by service members appear to be similar to
those of athletes and avid exercisers (13,22). For example, in
a group of Division I athletes (115 men, 88 women) from the
University of Nebraska, Froiland et al. (23) reported that nearly
50% used PSs. The most frequently consumed PSs were protein
powders (22%), whey protein (13%), and free AAs (12%). Male
athletes were more likely to use PSs than females, and athletes
participating in metabolically demanding sports including football,
soccer, wrestling, and track and field used PSs more frequently than
athletes participating in less metabolically demanding sports such
as golf, baseball, and softball. The use of PSs is also common in
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men and women who exercise regularly at local fitness clubs (24).
The patterns o f PS use among athlet es and routine exercisers across
sexes and activities of varying metabolic demands, and the reasons
for consuming PSs including improved muscle strength and power
and health promotion, are similar to those recently reported for
active-duty military personnel (3).
U.S. Military Dietary Protein and Energy
Guidelines: A Brief Overview
The current military DRI (MDRI) for protein is based on the RDA
from the Institute of Medicine (25) but incorporates adjustments
to meet requirements for periods of increasing metabolic demand,
which ra nge from 0.8 to 1.5 g kg
21
d
21
(26). The military
recommendations for dietary protein and energy are also consis-
tent with current nutrition recommendations for physically active
adults from the American College of Sports Medicine (8).
Recent data from NHANES 2003–2004 suggest that the
daily protein intake for adults of military age (19–60 y) should
be ;1.1–1.4 g kg
21
d
21
(27). As such, dietary protein intake
during nonoperational, garrison conditions is likely consistent
with the current MDRI and should be adequate for most physically
active warfighters when total energy intake is equival ent to
energy expenditure. Whether regular PS use confers any
additional metabolic advantages or disadvantages for war-
fighters w hen nutrition requirements are met has not been
determined.
Combat rations are the primary source of food during military
field training and when conducting missions in remote areas. The
nutritional standards for operational rations specify nutrient content
requirements for different types of rations and serve as the basis for
feeding policies that establish the allowable duration that the ration
can be used as the sole source of nutrition (26). General-purpose
rations, of which the most commonly used and best known is the
Meal, Ready-to-Eat, may be consumed as the only source of food
for up to 21 d (28). The daily issue of Meals, Ready-to-Eat (3/d) is
designed to be nutritionally adequate and cu rrently provides ; 3975
kcal d
21
and 125 g of protein. In contrast, restricted rations are
nutritionally incomplete and designed for certain operational
scenarios, such as long-range patrol and reconnaissance, when
weight and volume restrictions prev ent pr ovi sion o f suffic ie nt
food to meet energy expenditures. Warfighters are allowed
to subsist solely on energy-restricted rations, such as the Food
Packet, Long-Range Patro l ration, which contains 1500 kcal d
21
and 50 g of protein or the First Strike Ration, which provides
2900 kcal d
21
and 94 g of protein for periods #10 d.
Operational Stress and Potential
Metabolic Benefits of PSs
The metabolic cost of military operations is largely dependent
on occupation and the type of training being performed. Many
military occupations are relatively sedentary. Moreover, during
nonoperational, garrison conditions, most soldiers likely con-
sume sufficient energy to match energy expenditure and main-
tain body weight (29). In fact, many soldiers now overconsume,
because overweight and obesity rates in military personnel have
been increasing (30). In contrast, soldiers in the SF, U.S. Army
Rangers, and infantry expend more energy than do combat
support and combat service support soldiers due to sustained
periods of physical activity. For example, soldiers engaged in
various dismounted combat missions may expend 3500–4600
kcal d
21
(10). At the extremes, total energy expenditures for
Marines engaged in mountain warfare training have exceeded
7000 kcal d
21
(31,32). Physical overload is a contributing
factor to the increased metabolic cost of military training. The
loads carried can be substantial. Whereas the typical assault load
is ;25 kg, approach loads can be as high as 55 kg. Load carriage
substantially increases the physiological strain of locomotion,
because oxygen consumption, heart rate, and ventilation are
increased, and endurance capacity is markedly less (33,34). The
metabolic cost of load carriage increases proportionally as the
load becomes heavier (35).
Service members in these physically demanding occupations
often have very limited opportunities to eat during their missions,
and their energy intake is usually insufficient to balance energy
expenditure, resulting in energy deficits (10). As a consequence,
these warfighters are very dependent on between-mission meals
and snacks for refueling and metabolic recovery. It is well
described that prolonged energy deficit coupled with military
operational and environmental stressors can diminish fat-free
mass (FFM) (36) and alter bone mineralization (37) and immune
responsiveness (38), which may compromise military performance
(39), and increase musculoskeletal injury risk (40–42).
Nutritional strategies that increase total dietary protein intake
may mitigate the detrimental effects of operational stress by
providing energy and AAs necessar y to sustain whole-body
and skeletal muscle protein balance. Evidence strongly sug-
gests that consuming dietary protein in excess of the current
RDA defends FFM in response to sustained periods of negative
energy balance (36,43). Pikosky et al. (44) demonstrated
negative nitrogen balance in healthy young soldiers in response
to a 7-d period of exercise-induced energy deficit (21000 kcal d
21
)
when protein was consumed at amounts similar to the current
RDA (0.9 g kg
21
d
21
). However, doubling dietary protein intake
(1.8 g kg
21
d
21
) attenuated nitrogen loss and the resultant
negative nitrogen balance while also maintaining hepatic glucose
production in response to the 7-d energy deficit (44,45). Recent
findings from Mettler et al. (43) and Pasiakos et al. (46,47) confirm
the muscle-sparing and glycemic regulatory advantages gained
from consuming protein at amounts above the RDA. These data
suggest that FFM and hepatic glucose production are preserved in
response to energy deficit when protein intake is provided at
amounts at least twice the RDA. A PS, provided as a component
of a recovery-based combat ration, might be an effective method
to achieve protein intakes approaching 1.6 g kg
21
d
21
during
periods of unavoidable energy deficit. However, further study is
required to evaluate the efficacy of PS use by U.S. military
personnel during (or in recovery from) sustained periods of
increased metabolic demand and energy deficit.
In conclusio n, the rate of PS use among U.S. military personnel
appears to be similar to that in athletes and physically active adults
and much higher than in the general U.S. civilian population. The
frequency of PS use differs between sexes, age, rank, and military
occupations; warfighters with more metabolically demanding
occupations consume nearly twice the amo unt of PSs than those
with more sedentary jo bs. Most military personnel believe that
regular use of PSs will enhance muscle strength, improve perfor-
mance, and promote health, whereas others believe that consum-
ing PSs will assist with weight loss and provide energy. These ideas
and the decision to purchase PSs are not based on credible sources
butratheronclaimsreadinmagazinesandinformationobtained
from family and friends. Scientific evidence does indicate that
supplemental protein may confer metabolic advantages for
warfighters in some conditions, especially during periods of
sustained energy deficit when PS consumption can provide energy
and AAs necessary to attenuate decrements in FFM. However,
Protein supplement use among warfighters 1817S
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most warfighters consuming a normal, ad libitum diet meet their
energy and the recommended dietary protein requirements with-
out the need for consumption of PSs.
Acknowledgments
The authors thank Harris R. Lieberman and Krista G. Austin
for their support in the development of t his meeting and
manuscript. All of the authors drafted, read, and approved the
final manuscript.
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