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Prevalent Use of Dietary Supplements among People Who Exercise at a Commercial Gym

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Supplement use was surveyed in a convenience sample of persons who exercised regularly at a Long Island, NY gym. Participants, age at least 18 y, completed anonymous questionnaires. A majority (84.7 %) took supplements. Many consumed multivitamin/minerals (MVM; 45 %), protein shakes/bars (PRO; 42.3 %), vitamin C (34.7 %), and vitamin E (VE; 23.4 %) at least 5 times per wk. Other dietary supplements were used less frequently or by fewer participants. Ephedra was consumed by 28 % at least once per wk. Choices and reasons for dietary supplement use varied with age of the participant. More of the oldest consumed MVM or VE, while those 45 y or younger chose PRO. Those younger than 30 consumed creatine more frequently. The oldest participants took supplements to prevent future illness, while others took supplements to build muscle. The reason for committing to an exercise program influenced supplement use. Bodybuilders more frequently consumed PRO, creatine, and ephedra compared to those exercising for health reasons.
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481
International Journal of Sport Nutrition and Exercise Metabolism, 2004, 14, 481-492
© 2004 Human Kinetics Publishers, Inc.
Prevalent Use of Dietary Supplements
Among People Who Exercise
At a Commercial Gym
Laura J. Morrison, Frances Gizis,
and Barbara Shorter
Supplement use was surveyed in a convenience sample of persons who exer-
cised regularly at a Long Island, NY gym. Participants, age at least 18 y, com-
pleted anonymous questionnaires. A majority (84.7%) took supplements. Many
consumed multivitamin/minerals (MVM; 45%), protein shakes/bars (PRO;
42.3%), vitamin C (34.7%), and vitamin E (VE; 23.4%) at least 5 times per wk.
Other dietary supplements were used less frequently or by fewer participants.
Ephedra was consumed by 28% at least once per wk. Choices and reasons
for dietary supplement use varied with age of the participant. More of the
oldest consumed MVM or VE, while those 45 y or younger chose PRO. Those
younger than 30 consumed creatine more frequently. The oldest participants
took supplements to prevent future illness, while others took supplements to
build muscle. The reason for committing to an exercise program inuenced
supplement use. Bodybuilders more frequently consumed PRO, creatine, and
ephedra compared to those exercising for health reasons.
Key Words: athletic training, ephedra, ergogenic aids, nutrient supplementa-
tion
Since the passage of the Dietary Supplement Health and Education Act (DSHEA)
in 1994, a wide variety of compounds have become readily available in the United
States. A dietary supplement, according to DSHEA, includes one or more of the
following ingredients: vitamin, mineral, herb or other botanical, amino acid, con-
centrate, metabolite, constituent, and/or extract. Examples of these compounds
include creatine, ephedra, chromium picolinate, protein or carbohydrate bars/shakes,
and glutamine.
Studies have measured the extensive use of vitamin and mineral supplements
by Americans (1–3, 5–7, 12, 15, 17, 18, 25–27). Few studies have examined the
use of the other products included in DSHEA (15, 20), and little information is
available regarding supplement use among selected groups. Survey results have
shown that dietary supplements have been taken to improve performance, increase
strength, gain muscle mass, lose weight, prevent illness and disease, treat medical
problems, boost immunity, compensate for inadequate diet, provide extra energy,
meet special nutrient demands for high levels of physical activity, improve tness,
increase alertness or mental activity, reduce stress, and feel better (16, 17, 22, 24).
The authors are with the Nutrition Department at the C.W. Post Campus of Long Island Uni-
versity, Brookville, NY 11548.
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Supplement Use at a Commercial Gym
While some supplements may be benecial, others have been shown to have no
effect or to be dangerous. Many adverse effects from the use of various supplements
have been reported to the FDA (4).
People who frequent commercial gyms may use particular supplements for a
variety of reasons. Differences may exist in the choice of supplement depending on
age, gender, or reason for exercise. It is important to determine what supplements
people who exercise take, why they take them, and their sources of information in
order to help health professionals educate this population. Some people may learn
about supplements from unqualied sources rather than health professionals. Eliason
et al. (6) found that participants who purchased supplements at a health store did not
rely on physicians or other health professionals for supplement information. This
study examined the use of supplements by people who exercise and determined
the source from which these people obtained information.
Methods and Materials
Selection of Population
To be included in this study, subjects attending a commercial gym in a suburb
of Long Island, NY exercised at least 4 times per wk at 1 h per session, and had
been exercising at this intensity for at least 1 y. A preliminary questionnaire was
administered, regarding the above criteria. A convenience sample of 222 people,
18 y and older, met qualication standards and completed the survey.
Questionnaire
The survey included questions concerning demographic characteristics such as
age, gender, education, employment, and health status. Data concerning type and
frequency of supplement use, reasons for supplement use, main reason for exercis-
ing, and sources of supplement information were collected. The anonymous survey,
consisting of 25 questions, was developed based on previously published studies
(5–7,17, 21, 25, 26). It was reviewed and evaluated by faculty, colleagues, and
registered dietitians for readability and content validity. A similar population at 2
different gyms on Long Island, New York pilot tested the questionnaire.
Data Collection
Surveys were distributed and collected on the same day by the researcher. Fol-
lowing completion of the questionnaire, each participant was given an energy bar
and asked if they had forgotten to list any supplements. If so, they were given the
opportunity to make the appropriate revisions. Data were collected over a period
of 2 d by 1 researcher (LM).
Data Analysis
Analyses of data were performed using SPSS for Windows (v. 10.0, SPSS Inc.,
Chicago, IL). Descriptive statistics including frequency distribution were devel-
oped. When data were incomplete, a reduced n was used. Comparisons were made
by chi square. Differences were considered signicant if the P value was < 0.05.
Group-by-group comparisons were considered signicant at P < 0.017 (Bonfer-
roni correction).
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Morrison, Gizis, and Shorter
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Supplement Use at a Commercial Gym
Results
Demographics
Participants of the study were primarily male (82.0%) and Caucasian (80.4%). A
majority of the subjects (86.4%) attended or had graduated from college, and 19.0%
had started or completed advanced degrees. Almost half (46.5%) of the subjects
reported working in business, while 21.7% had other, unspecied occupations.
Participants considered themselves to be healthy; excellent health was reported
by 50.7% and good health by 43.9%. The population tended to be young; 52.3%
were 30 y or younger (Table 1A). For comparative purposes, 3 age groups were
established: Group 1, participants who were 18 to 30 y (n = 113); Group 2, 31 to 45
y (n = 68); and Group 3, 46 y and older (n = 35). Data were not analyzed separately
for females because of the small numbers in the survey (n = 40).
The types of exercise reported in Table 1B included weightlifting by 86.4%
of participants, endurance/cardiovascular exercise by 73.6%, and strength training
by 53.6 %. Few (16.8%) reported engaging in circuit training.
Table 1A Age of Subjects Exercising at a Commercial Gym
Age of subjects N %
18–20 14 6.5
21–25 59 27.3
26–30 40 18.5
31–35 32 14.8
36–40 21 9.7
41–45 15 6.9
46–50 15 6.9
51–55 13 6.0
56–60 5 2.3
> 60 2 0.9
Note. Missing data n = 6; 2.7%.
Table 1B Types of Exercise at a Commercial Gym
Type of exercise N %
Weightlifting 190 86.4
Endurance/cardiovascular 162 73.6
Strength training 118 53.6
Circuit training 37 16.8
Note. More than 1 response possible. Missing data n = 2; 0.9%.
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Supplement Use at a Commercial Gym
Supplement Use
A majority (84.7%) of the subjects reported taking at least 1 supplement, and
93.4% of these persons had been taking them for at least 1 y. Of those using these
products, 94.5% consumed supplements throughout the year, and only 5.5% took
them during specic seasons. Participants were asked to reveal the types and
frequency of use of all the supplements they were consuming at the time of the
study (Table 2).
The four that were taken “regularly” (more than 5 times per wk) by the
largest proportion of the participants included: multivitamin and minerals (MVM;
45.0%), protein shakes/bars (PRO; 42.3%), vitamin C (34.7%), and vitamin E
(23.4%). Also used on a regular basis were calcium (17.1%), B complex vitamins
(16.2%), carbohydrate shakes/bars (14.4%), glutamine (14.0%), ephedra/Ma Huang
(13.1%), and creatine (12.6%).
When comparing supplement use by age group (Table 3), more of those in
Group 3 (46 y and older) consumed multivitamin and mineral supplements com-
pared to participants in Group1 (ages 18 to 30 y; P = 0.006). A higher percentage
of those in Group 3 regularly consumed vitamin E compared to those in either
Group 2 (P = 0.0003) or Group 1 (P = 0.0001)
Supplement use was also categorized as taken or not taken. Taken included
the categories regularly, occasionally, and seldom. Protein shakes/bars were taken
by 54.9% of participants, creatine (33.3%), carbohydrate shakes/bars (30.2%),
ephedra/Ma Huang (27.9%), glutamine (27.1%), chromium picolinate (18.9%),
carnitine (16.7%), ginseng (16.2%), arginine (14.9%), ornithine (13.5%), and
androstenedione (13.1%).
When data were compared by age group as taken or not taken (Table 4), the
use of 3 supplements varied signicantly by age group. An increased use of vitamin
E by the oldest participants in Group 3 was identied, compared to the younger
participants in Group 1 (P = 0.017). In addition, more in the 2 younger Groups 1
(P = 0.004) and 2 (P = 0.005) selected protein shakes/bars compared to the oldest
participants of Group 3. More of the youngest subjects of Group 1 chose creatine
compared to the oldest participants of Group 3 (P = 0.001).
Reasons for Supplement Use
Participants who could list as many reasons as desired indicated that supplements
were chosen to build muscle (49.1%), prevent future illness (38.4%), increase energy
Table 1C Main Reason for Exercising at a Commercial Gym
Reason N %
Bodybuilding 65 29.7
Health reasons 43 19.6
Endurance/cardiovascular 19 8.7
Weight loss 18 8.2
Improve performance in a sport 16 7.3
Note. Missing data n = 61; 27.5%.
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Supplement Use at a Commercial Gym
(36.1%), improve performance in a sport (24.4%), gain strength (22.4%), and aid
in recuperation (20.5%). Other reasons for taking supplements were reported less
frequently.
Three reasons for taking supplements varied signicantly by age group (Table
5). More in Groups 1 (P = 0.0002) and 2 (P = 0.0001) took supplements to build
muscle compared to the older participants of Group 3. More of the oldest participants
in Group 3 consumed supplements to prevent future illness or disease compared to
the youngest participants in Group 1 (P = 0.009). There was some trend that more
of the youngest participants (Group 1) chose supplements to gain strength compared
to Group 2 (P = 0.028) and Group 3 (P = 0.027). Although the overall comparison
of the 3 groups indicated a signicant difference by age group, group-by-group
comparisons were not signicant at the P < 0.017 level. Participants (15.3%, n =
34) who reported not taking supplements believed that they do not work (38.2%)
and that enough nutrients were obtained from their diet (35.3%).
Table 2 Supplements Used By Subjects Who Exercise at a Commercial Gym
Regularly Occasionally Seldom Never
Supplement n % n % n % n %
Multivitamin/mineral 100 45.0 26 11.7 15 6.8 81 36.5
Multivitamin/no mineral 19 8.6 16 7.2 13 5.9 174 78.4
B-complex 36 16.2 14 6.3 12 5.4 160 72.1
Vitamin C 77 34.7 24 10.8 11 5.0 110 49.5
Vitamin E 52 23.4 18 8.1 14 6.3 138 62.2
Other antioxidants 14 6.3 2 0.9 7 3.2 197 89.1
Iron 23 10.4 9 4.1 20 9.0 170 76.6
Calcium 38 17.1 10 4.5 15 6.8 159 71.6
Chromium picolinate 18 8.1 11 5.0 13 5.9 180 81.1
Carbohydrate shakes/bars 32 14.4 19 8.6 16 7.2 155 69.8
Protein shakes/bars 94 42.3 20 9.0 8 3.6 100 45.0
Glutamine 31 14.0 14 6.3 15 6.8 162 73.0
Carnitine 15 6.8 8 3.6 14 6.3 185 83.3
Arginine 8 3.6 10 4.5 15 6.8 189 85.1
Ornithine 9 4.1 6 2.7 15 6.8 192 86.5
Creatine 28 12.6 24 10.8 22 9.9 148 66.7
Other amino acids 4 1.8 2 0.9 6 2.7 210 94.6
Androstenedione 4 1.8 3 1.4 22 9.9 193 86.9
Yohimbe 4 1.8 9 4.1 11 5.0 198 89.2
Ginseng 8 3.6 12 5.4 16 7.2 186 83.8
Ephedra/Ma Huang 29 13.1 18 8.1 15 6.8 160 72.1
Dehydroepiandrosterone
(DHEA) 6 2.7 4 1.8 11 5.0 201 90.5
Other herbs 6 2.7 0 0.0 2 0.9 210 94.6
Other 13 6.0 2 0.9 0 0.0 202 91.0
Note. Regularly = greater than 5 times per wk; occasionally = 2 to 4 times per week; seldom =
1 to 2 times per wk or less; never = not taken.
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Supplement Use at a Commercial Gym
Table 3 Comparison By Age for Supplements Taken Regularly Versus
Occasionally, Seldom, or Never
Group 1 Group 2 Group 3
(age 18 to 30; (age 31 to 45; (age 46+;
n = 113) n = 68) n = 35)
Supplement
a
n % n % n % P
b
Multivitamin and mineral
c
Regularly 40 35.4 36 52.9 21 60.0
Sometimes,
occasionally, never 73 64.6 32 47.1 14 40.0 .010
Vitamin E
d
Regularly 18 15.9 13 19.1 19 54.3
Sometimes,
occasionally, never 95 84.1 55 80.9 16 45.7 .0001
Note. Regularly = greater than 5 times per wk, occasionally = 2 to 4 times per wk, seldom =
1 to 2 times per wk.
a
Comparisons for all other supplements not signicantly different;
b
chi
square.
c
Group 1 signicantly different from Group 3 (P = 0.006);
d
Group 3 signicantly
different from Group 1 (P = 0.0001) and Group 2 (P = 0.0003).
Table 4 Supplements “Taken” Compared By Age
a
Group 1 Group 2 Group 3
(age 18 to 30; (age 31 to 45; (age 46+;
n = 113) n = 68) n = 35)
Supplement
a
n % n % n % P
b
Vitamin E
c
Taken 39 34.5 23 33.8 20 57.1 .038
Not Taken 74 65.5 45 66.2 15 42.9
Protein shakes/bars
d
Taken 67 59.3 41 60.3 11 31.4 .009
Not taken 46 40.7 27 39.7 24 68.6
Creatine
e
Taken 47 41.6 22 32.4 4 11.4 .004
Not taken 66 58.4 46 67.6 31 88.6
Note. “Taken” = the categories regularly, occasionally, and seldom.
a
Comparisons for all
other supplements are not signicantly different;
b
chi square.
c
Group 3 signicantly different
from Group 1 (P = 0.017);
d
Group 3 signicantly different from Group 1 (P = 0.004) and
Group 2 (P = 0.005);
e
Group 3 signicantly different from Group 1 (P = 0.001).
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487
Supplement Use at a Commercial Gym
Main Reason for Exercise
One item in the questionnaire asked subjects to indicate their main reason for exer-
cise; however, 27.5% (n = 61) reported more than 1 reason so that data from these
participants could not be further analyzed. The main reason for exercise reported
by the 161 participants who correctly answered this question (Table 1C) was body-
building (29.7%) followed by health reasons (19.6%). Other responses were less
frequently reported, and thus data were not further analyzed [endurance/cardiovas-
cular (8.7%), weight loss (8.2%), improve performance in a sport (7.3%)].
As shown in Table 6, of those participants who exercised for bodybuilding (n
= 65): 72.3% selected protein, 61.5% multiple vitamin and mineral supplements,
52.3% creatine, 49.2% ephedra, 49.2% vitamin C, 43.1% glutamine, and 36.9%
carbohydrates. For those subjects who exercised for health reasons (n = 43), 60.5%
chose multiple vitamin and mineral supplements, 44.2% protein, 41.9% vitamin
C, 37.2% vitamin E, 27.9% calcium, and 25.6% creatine. Comparison of supple-
ment use by those who exercised for bodybuilding or health reasons indicated that
signicantly more of those who took supplements for bodybuilding took protein
shakes/bars (P = 0.003), creatine (P = 0.006), or ephedra (P = 0.0001).
Sources of Information
To learn about supplements, the following sources of information were used by
more than half of the participants: magazines (65.8%), family/friends (63.1%),
Table 5 Reason for Taking Supplements Compared By Age
Group 1 Group 2 Group 3
(age 18 to 30; (age 31 to 45; (age 46+;
n = 113) n = 68) n = 35)
Reason
a
n % n % n % P
b
To build muscle
c
Take at least 1
supplement 63 56.3 37 55.2 6 17.1
No supplement 49 43.8 30 44.8 29 82.9 .0001
To prevent future illness
d
Take at least 1
supplement 35 31.3 29 42.6 19 55.9
No supplement 77 68.8 39 57.4 15 44.1 .026
To gain strength
e
Take at least 1
supplement 34 30.1 10 15.4 4 11.4
No supplement 79 69.9 55 84.6 31 88.6 .018
Note. More than one response possible.
a
Comparisons for all other reasons are not signicantly
different;
b
chi square.
c
Group 3 signicantly different from Group 2 (P = 0.0001) and Group 1
(P = 0.0002);
d
Group 3 signicantly different from Group 1 (P = 0.009);
e
Group 1 compared
to Group 2 (P = 0.028) and Group 3 (P = 0.027).
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489
Supplement Use at a Commercial Gym
personnel at a vitamin/health food store (55.7%), and books (54.5%). Many subjects
(45.5%) relied on the media and 38.7% on personal trainers. A third or fewer of the
participants indicated consulting a physician (33.8%), registered dietitian/certied
dietitian/nutritionist (28.4%), pharmacist (17.1%), and/or chiropractor (16.4%) for
supplement information. Approximately 49% of subjects who took supplements
reported checking qualications of those who supplied them with information.
Discussion
Previous studies have shown that subjects tend to underreport their supplement use
(7, 13). The current study followed the recommendations of Hensrud et al. (13).
Written responses about supplement use were followed by a discussion to determine
Table 6 Main Reason for Exercise Versus Supplementation
Bodybuilding Health reasons
(n = 65) (n = 43)
Supplement n % n %
Multivitamin with minerals 40 61.5 26 60.5
Multivitamin without minerals 15 23.1 7 16.3
B-complex 17 26.2 11 25.6
Vitamin C 32 49.2 18 41.9
Vitamin E 19 29.2 16 37.2
Other antioxidants 5 7.7 8 18.6
Iron 16 24.6 9 20.9
Calcium 16 24.6 12 27.9
Chromium picolinate 13 20.0 9 20.9
Carbohydrate shakes/bars 24 36.9 12 27.9
Protein shakes/bars
a
47 72.3 19 44.2
Glutamine 28 43.1 8 18.6
Carnitine 14 21.5 7 16.3
Arginine 12 18.5 6 14.0
Ornithine 10 15.4 6 14.0
Creatine
a
34 52.3 11 25.6
Other amino acids 6 9.2 4 9.3
Androstenedione 9 13.8 8 18.6
Yohimbe 10 15.4 4 9.3
Ginseng 12 18.5 9 20.9
Ephedra/Ma Huang
a
32 49.2 7 16.3
Dehydroepiandrosterone (DHEA) 7 10.8 4 9.3
Other herbs 1 1.5 3 7.3
Other 3 4.8 5 11.9
Note. More than 1 response for supplementation possible per reason.
a
Signicantly different:
protein shakes/bars (P = 0.003), creatine (P = 0.006), ephedra/Ma Huang (P = 0.0001).
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Supplement Use at a Commercial Gym
if any additional supplements may have been taken. The participants were given
the chance to make appropriate revisions as needed.
In this study, a higher percentage of subjects reported taking supplements
(84.7%) compared to reports of other populations (7, 15, 26, 27). Previous research
and the results of the current study have shown that vitamins and minerals were the
most frequently chosen supplements (5, 7, 15, 18, 29). Few studies have reported
the use of supplements, such as protein or carbohydrate shakes/bars, glutamine,
ephedra/Ma Huang, creatine, chromium picolinate, or other botanicals (15, 20).
In this study, many participants (42.3%) consumed protein shakes/bars and from
8% to 14% reported selection of carbohydrate shakes/bars, glutamine, ephedra,
creatine, or chromium picolinate on a regular basis (greater than 5 times per wk).
The Commission on Dietary Supplement Labels indicated that ephedra was
one of the top 10 botanical products sold in selected U.S. health food stores in
1995 (23). In the present study, ephedra was supplemented “regularly” by 13.1%
and taken at least 1 to 2 times per wk by 27.9% of subjects. The use of ephedra
has been of concern because it has been linked to several deaths and to more than
800 adverse effects since 1998 (4, 9, 11, 24).
Kamber et al. (14) analyzed 75 products used for sports supplementation
and found that some supplements contained caffeine and ephedrine when the
compounds were “either not or not clearly declared on the labels.” Interestingly,
the current study found that approximately 7 participants took supplements that
contained ephedra as one of its ingredients, but the participants did not list ephedra
as a supplement that they took. It is troubling that more supplements may have been
taken by this population that contained ephedrine. It was only after the completion
of the study that the researcher was made aware that some of the products listed in
the questionnaire might have contained ephedra even though the company might
not have indicated it.
Few studies have compared supplement use by age group. In the present study,
more older people tended to take multivitamin and mineral supplements and vitamin
E regularly compared to younger people. More younger subjects in the present
study consumed protein shakes/bars and creatine compared to older participants,
although these supplements may not have been taken as frequently as 5 times per
wk (regularly). Kaufman et al. (15) found that older persons took multivitamin and
minerals supplements, while more younger men tended to take creatine.
Consistent with previous studies, many persons took supplements to build
muscle, prevent future illness, increase energy, improve performance in a sport,
gain strength, or aid in recuperation (6, 17, 18, 23). The older people reported using
supplements to prevent future disease or illness, while participants younger than 45
took at least 1 supplement to build muscle. Neuhouser et al. (18) showed that their
subjects, who had a mean age of 44, took multivitamins to feel better, vitamin C to
prevent acute illness, and vitamin E and calcium to avoid chronic disease. Because
the number of older respondents in the current study is relatively small, further
analysis with a larger representation of older persons is warranted.
Comparisons were made for those subjects who reported that their main
reason for exercise was bodybuilding (n = 65) and health reasons (n = 43). More
of the bodybuilding group took the supplements creatine, protein shakes/bars, and
ephedra that have been shown to aid or have been marketed for bodybuilding.
Bodybuilders often use creatine to increase muscle creatine and phosphocre-
atine and enhance athletic performance (8, 10, 15). Ephedra, now banned, was
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Morrison, Gizis, and Shorter
491
Supplement Use at a Commercial Gym
usually used for weight loss and was marketed for weight loss as well as enhanced
athletic performance (24). The use of carbohydrate supplements by 36.9% of
bodybuilders was unexpected, because many bodybuilders tend to follow a high
protein, low carbohydrate diet. Many participants refused the energy bar that was
offered to them after the completion of the questionnaire because it “contained too
much carbs.” Carbohydrate supplementation has been shown to aid in prolonged,
low- and moderate-intensity exercise (21). Neuhouser et al. (18) found that those
people who reported that their main purpose for exercise was for health reasons
used multivitamin and mineral supplements, vitamin C, vitamin E, and calcium
as supplements to stay healthy and prevent future illness. Kaufman et al. (15) also
found that supplements were used for nonspecic health reasons.
Consistent with Eldridge and Sheehans study (5), many participants
reported using the following sources of information regarding supplement use:
magazines, family/friends, personnel at a vitamin/health food store, and books.
One-third (34%) consulted physicians, which is consistent with previous stud-
ies (7, 18, 24, 28). Health professionals such as registered dietitians or certied
dietitian/nutritionists and pharmacists were infrequently consulted. Eliason et al.
(6) found similar results.
In conclusion, many people who exercised extensively at a commercial gym
took dietary supplements. A wide variety of vitamin and mineral supplements as
well as other herbs and botanicals were chosen. At the time of this study 28% of
the participants reported taking ephedra, and 7 additional subjects did not realize
that they were doing so. Age of the respondent inuenced the choice of supplement
and the reason for taking supplements. Participants also chose different supple-
ments, depending on their main reason for exercising. Health professionals were
least frequently consulted for supplement information. Gyms, such as the one
included in this study, may well need to have qualied health professionals such
as nutritionists available to members. These professionals can provide accurate
information about supplements and assist members to be aware of both positive
as well as adverse health effects of dietary supplements.
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Acknowledgments
The authors would like to thank the gym and the study participants for their cooperation.
Thanks also goes to Alessandra Sarcona for her assistance.
... Also, fitness centers sell MEDS and are believed to stimulate use among members [31]. In support of this, studies have found that Norwegian adolescents [24], and American and Brazilian adults [31,32], who were members at a fitness center, are frequent users. ...
... Among males, being a fitness center member explained most of the variance in MEDS use, indicated by being four times more likely to use MEDS compared to not being a member. This result is in line with findings among Norwegian high school students [24] but contributes with new in-depth information with regards to adults [31,32]. Also, in line with findings among high school students, although a higher physical activity level slightly increased the odds of using MEDS in males, our findings are of no coherence between use of MEDS and participation in organized sports [24]. ...
... In males, reporting to exercise "to increase muscle mass" almost doubled the odds of using MEDS, which supports previous findings among male American fitness center members [32]. This might be expected, as those who aim to enhance muscle strength might be more receptive to advertisement claiming to give you a quick fix to improve muscle strength. ...
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Background: Use of dietary supplements (DS) and muscle enhancing dietary supplements (MEDS) is frequent among students despite the lack of evidence of effects and health risks related to consumption. We need to increase our understanding of students' motivation, examine potential gender differences, and explore explanatory factors, to address preventive measures related to use. Therefore, this study aimed to explore the frequency of, and the reasons for, DS use among university students, as well as explanatory factors for use of MEDS. Method: Male and female students from nine Norwegian universities participated in this cross-sectional study. Participants responded to questions about demographics, DS and MEDS use, internalization of body ideals, physical activity- and exercise level, motives for exercise, and exercise context. Independent t-test, Chi-square test, Pearson's correlation, and logistic regression were used to investigate between group differences, associations, and explanatory factors for use, respectively. P-values ≤ 0.05 were defined as significant. Results: A total of 1001 males (34%) and females, with a mean(sd) age of 24.21(4.76) years, participated. The frequency of DS use was 42% and 40% (p = .414) in males and females, respectively, in which more males than females used DS to improve physical or mental performance (p = < .001), increase muscle mass (p = < .001) and weight for health (p = .014), and improve appearance (p = < .001). In males and females, respectively, 25% and 10% used MEDS (p = < .001). In males, being a fitness center member (OR:3.80), exercising to improve muscle mass (OR:1.96), and a higher physical activity level (OR:1.09) positively explained MEDS use, while exercising to increase endurance (OR:0.49) and being an exercise science student (OR:0.47) negatively explained MEDS use. In females, internalizing the athletic body ideal (OR:1.78) and exercising to improve muscle mass (OR:1.74) positively explained MEDS use. Conclusions: Our main findings indicate that a surprisingly high percentage of male and female Norwegian students use DS and MEDS, and that reasons for use, and variables explaining the variability in frequency of use, differ between genders. Longitudinal studies to investigate direction of associations are needed in future research.
... Nevertheless, the prevalence of dietary supplements use we found (81.31%) is higher than described in most recent studies in gym users (36.8-43.8%) [5,[34][35][36], but it is closer to what is reported by Morrison et al. (2004) in USA gym trainees (84.7%) [37]. It is interesting to note that in international athletes and professional bodybuilders the prevalence of the use of supplements is 82.2% and 100%, respectively [4,32]. ...
... Nevertheless, the prevalence of dietary supplements use we found (81.31%) is higher than described in most recent studies in gym users (36.8-43.8%) [5,[34][35][36], but it is closer to what is reported by Morrison et al. (2004) in USA gym trainees (84.7%) [37]. It is interesting to note that in international athletes and professional bodybuilders the prevalence of the use of supplements is 82.2% and 100%, respectively [4,32]. ...
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Background: Among athletes, bodybuilders are more predisposed to the use of dietary supplements (DS) and hormones (H) to increase in adaptations to physical training and performance. The purpose of the study was to identify social, psychological, and organisational factors that are associated with the use of food supplements and hormones in young bodybuilders of the metropolitan area of Naples. Methods: 107 athletes, practicing bodybuilding, were consecutively recruited in 30 gyms, randomly selected in the metropolitan area of Naples. Athletes were administered an anonymous questionnaire. The questionnaire consists of 5 sections (socio-demographic, frequency and reasons for bodybuilding, knowledge, attitudes and behaviours). Descriptive statistics were performed using T-test and Chi-square statistics. A score was created for knowledge, attitudes, behaviours. Multivariable logistic regression models were employed to assess association between each score and the use of DS and H. Statistical analyses were carried out using STATA 15. Results: 81.31% of the subjects reported to use DS while 35.51% H. Females are less likely to practise bodybuilding frequently than males (OR 0.18 (95% CI 0.05-0.69), p = 0.01). Subjects who have attended high school or university have a lower probability of taking DS (OR 0.17 (95% CI 0.04-0.65), p = 0.01). H users also use supplements more frequently (OR 61.21 (95% CI 3.99-939.31), p < 0.001). Those who scored higher on knowledge scores are more likely to take DS (OR 1.53 (95% CI 1.11-2.12), p < 0.001). Attitudes are correlated with the use of DS; those who scored higher were less likely to use DS (OR 0.77 (95% CI 0.30-0.98), p = 0.03). People who use DS are 30 times more likely to use H at the same time (OR 30.25 (95% CI 2.51-365.24), p < 0.001). Subjects who have a higher score for knowledge and attitudes are less likely to use H (OR 0.68 (95% CI 0.54-0.87), p < 0.001, OR 0.75 (95% CI 0.62-0.90), p < 0.001). Conclusions: Prevalence of H and DS' use, although lower than reported in the literature, is a worrying public health problem. Better knowledge can lead to an informed use. Gym instructors should be trained to provide accurate and scientifically sound information. Health professionals should combine their expertise to provide more comprehensive guidance to the exercisers.
... Dietary supplements (DS) are food products containing dietary ingredients intended to supplement the diet with more nutritional value, and they include vitamins, minerals, amino acids, herbs or botanicals, and other substances [1]. There is a lot of evidence on the widespread use of DS in various countries [2][3][4][5][6][7][8][9]. In Saudi Arabia, many studies have shown that the consumption of DS is becoming increasingly popular, particularly among fitness center attendees. ...
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Saudi Arabia has witnessed recent reforms and positive socio-political changes that have led to increased opportunities for women to participate in fitness centers. This study investigated protein supplement consumption among Saudi females compared with that among males and examined the knowledge and attitudes of the participants toward protein supplement use. A cross-sectional study was conducted in Riyadh using a previously validated, self-administered online survey. The questionnaire included items related to the prevalence, knowledge, attitudes, and practice of protein supplementation. The participants were 354 adults (58.2% were females). The results showed that over 47% of the participants attended fitness centers with more male (80.3%) than female (41%) attendees. Nearly 50% of the participants consumed protein supplements, with males (68.7%) using significantly (p < 0.001) more protein supplements than females (35.6%). The powdered form was most commonly consumed. The percentage of gym attendees (67.8%) who used protein supplements was higher than that among non-gym attendees (32.2%). Gaining muscles (56.1%) followed by compensating for protein deficiency (28.6%) were the reasons for taking protein supplements, with a significant gender difference (p < 0.001). Coaches provided the most information on protein supplements. The participants appeared to be knowledgeable about protein supplements. Although over 68% of protein supplement users suffered from various symptoms, only 20% of the participants thought that there was no risk in taking protein supplements, with significant gender differences. It was concluded that Saudi male participants are twice more likely to attend the gym and consume protein supplements compared with females. Of both genders, those attending the gym consumed more protein supplements than non-gym attendees.
... 8 The literature on NS usage among gym users globally is still scant, with these few studies concentrated in developed countries. [9][10][11][12] There is an increased influx of recreation centers or gyms in Kampala city of Uganda, leading to the continued demand for NS. The misuse of these products is concerning, particularly arising from high dosage and mixed usage. ...
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Background: This study focused on investigating the prevalence of nutritional supplement (NS) usage, establishing their source and the motivating factors for the usage of NS among Gym users in Kampala city, Uganda. Methods: The study employed a cross-sectional research design. Multistage random sampling techniques were used to select 45 gym users among the 5 divisions that constitute Kampala city. Data were collected using questionnaires and analyzed using SPSS Version 26, where means, SD, frequencies and percentages were obtained. Chi-square tests were used for categorical comparisons between variables. Results: The results showed that there were more male participants (62.2%) than female participants (37.8%). The majority (76.9%) of gym users obtained NS from retail stores such as pharmacies, (10.2%) from their sports coaches, (7.7%) nutritionists/dieticians, and (5.1%) from team mates. Non-professional gym users (62.3%) reported higher levels of energy drink consumption than professional gym users (26.7%). The consumption of vitamins, herbal products and proteins was also considerably high. We also identified coaches/trainers (30.8%) as the main source of information, followed by nutritionists/dieticians (23.1%) and online websites (20.5%). Most gym users strongly agreed that supplements increase endurance training, increase strength, and make one healthier. Conclusions: The prevalence of nutritional supplement usage among gym users was high, with energy drinks and herbal products being the most preferred supplements.
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Background Protein supplements have become a widespread practice amongst athletes and gym users worldwide. However, studies on the use of protein supplements among female gym users in Saudi Arabia are lacking. Objective The aim of this study was to investigate the prevalence of protein supplement usage among female gym users and their attitudes towards protein supplementation in Riyadh city, Saudi Arabia. Methods In this cross-sectional study, 502 female gym users aged ≥18 years completed a structured, self-administered online questionnaire on the usage of protein supplementation. Socio-demographic information, anthropometry, health status, exercise frequency, attitudes and knowledge regarding protein supplements were obtained. Results The overall prevalence rate of protein supplement use among the study respondents was 36.3%. There were significant associations between the use of protein supplements and educational level (p< 0.05), the duration of being a gym member (p< 0.05) and frequency of gym visits per week (p< 0.05). Whey protein was the predominantly used supplement (57.8%), and the reason attributed to the use of protein supplement was muscle building (53.9%). The main sources of information regarding protein supplement use included the internet (30.2%) followed by gym coaches (25.3%). Conclusion Our findings demonstrated that a considerable number of females exercising in gyms use protein supplements, and most rely on unreliable sources for decision-making of protein supplements use. Nutritional education and consultations regarding protein supplement use are warranted.
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The American Dietetic Association maintains that healthy adults can meet nutritional requirements through a balanced diet and, therefore, vitamin/mineral supplements are not generally needed (1). However, 40% to 60% of US adults regularly use such supplements (2-5). Although a number of studies have examined the extent of supplementation, fewer studies have considered possible behavioral correlates of supplement use. Two studies (2,6) examined whether supplement use is related to 'locus of control' (LOC), which gauges whether an individual attributes causes of events to internal or external factors. Some evidence indicates that individuals who feel responsible for their health (high internal LOC) are more likely to take supplements. The objectives of our study were to expand upon these previous studies by examining the relationship of supplementation to LOC, nutrition attitudes, and emotional well-being.
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Data from the 1987 National Health Interview Survey show that 51.1% of the adults aged 18-99 years in the United States consumed a vitamin/mineral supplement in the past year, but that only 23.1% did so daily. Whites, women, and older individuals were more likely than blacks, men, and younger individuals to consume supplements regularly. Multivitamins were the most commonly consumed supplement, followed by vitamin C, calcium, vitamin E, and vitamin A. Results suggest that supplementation practices have changed little since the 1970s. Results regarding the amounts of nutrients obtained from supplements show that a food frequency type of methodology collects reasonably accurate data reflecting intake of supplements over the past year. Few, if any, individuals were consuming nutrients in amounts considered toxic. Although vitamin and mineral supplementation is a common health habit, it appears not to pose a significant health risk for most of the population.
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Vitamin/mineral supplements are often used by athletes as ergogenic aids to improve performance. This paper reviews studies of the prevalence, patterns, and explanations for vitamin/mineral supplement use among athletes. Fifty-one studies provided quantitative prevalence data on 10,274 male and female athletes at several levels of athletic participation in over 15 sports. The overall mean prevalence of athletes' supplement use was 46%. Most studies reported that over half of the athletes used supplements (range 6% to 100%), and the larger investigations found lower prevalence levels. Elite athletes used supplements more than college or high school athletes. Women used supplements more often than men. Varying patterns existed by sport. Athletes appear to use supplements more than the general population, and some take high doses that may lead to nutritional problems. Sport nutritionists should include a vitamin/mineral supplement history as part of their dietary assessment so they can educate athletes about vitamin/mineral supplements and athletic performance.
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Vitamin/mineral supplements are consumed by adolescent athletes motivated both by general health concerns and a desire for improved athletic performance. Supplement use by high school athletes was examined using a questionnaire administered to 742 athletes at all nine schools in one rural county. A total of 38% used supplements, with supplement use not differing by gender or grade in school. Athletes with aspirations to participate in college sports more often consumed supplements. Healthy growth, treating illness, and sports performance were the most important reasons for supplement use, with parents, doctors, and coaches being the greatest influences on use. Most athletes (62%), especially boys, believed supplement consumption improved athletic performance. Supplement use by these adolescents appears to be motivated more by health reasons than sports performance. It is suggested that it may be useful to assess vitamin/mineral supplement use by adolescents and to provide education and counseling about diet, nutrition, and exercise for those who use them as ergogenic aids to improve athletic performance.