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Sánchez Oliver, A.; Miranda León, Ma T.; Guerra Hernández, E.

Prevalence of protein supplement use at gyms

Nutrición Hospitalaria, vol. 26, núm. 5, septiembre-octubre, 2011, pp. 1168-1174

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Nutr Hosp. 2011:26(5):1168-1174ISSN 0212-1611 • CODEN NUHOEQ

S.V.R.318

Original

Prevalence ofprotein supplement use at gymsA. Sánchez Oliver', M: T. Miranda León' andE. Guerra-Hernández'

'Departamento de Nutrición y Bromatología. Facultad de Farmacia. Universidad de Granada. Granada. 'Departamento deBioestadistica. Facultad de Medicina. Universidad de Granada. Granada. Spain.

Abstract

At the present time, the abuse of all c1assof sport nutri­tional supplements (NS) has extended the people who goregularly to gymnasiums. Between these substances thereare the Protein Powder Supplements (PPS). The purposeofthis study is to examine the consumption ofPPS in 415individuals from Seville fitness centers.

AII individuals were evaluated with anthropometricmeasurements and completed a questionnaire previouslyreviewed, evaluating the validity of the content, applica­tion, structure and presentation.

28% ofthe individuals were using or used PPS. Ofthetotal, 42.7% ofmale individuals compared to 3.2% ofthefemales. The use of PPS was higher than what has beenreported in previous studies about supplement use infitness center, 28% vs 10-14% aprox.

The SPP use is associated with sex, age, and time ofsport practiced.

More than a 25 % of the total individuals that attend agym use PPS. The total individuals that attend a gym anduse PPS far exceed the RDA of protein for general popu­lation and/or athletes, being able to cause problems ofhealth.

(Nutr Hosp. 2011;26:1168-1174)

DOI:I0.330S/nh.2011.26.S.S110Key words: Exercise. Physical activity. Powder protein

supplement. Fitness center. Questionnaire.

Abbreviations

SN: Suplementos nutricionales.NS: Nutritional supplements.SPP: Suplementos Proteicos en Polvo.

Correspondence: Eduardo Guerra Hernández.Departamento de Nutrición y Bromatología.Facultad de Farmacia. Universidad de Granada.Campus Universitario de Cartnja.18012 Granada. Spain.E-mail: ejguerraceugr.es

Recibido: I5-XI-20lO.Aceptado: 20-I1I-20l0.

1168

ESTUDIO ESTADÍSTICO DEL CONSUMODE SUPLEMENTOS PROTEÍCOS EN GIMNASIOS

Resumen

En la actualidad, el abuso de toda clase de suplementosnutricionales (SN) deportivos se ha extendido a laspersonas que acuden a gimnasios regularmente. Entreestas sustancias están los Suplementos Proteicos en Polvo(SPP). El objetivo del presente estudio es evaluar elconsumo de suplementos proteicos en un grupo de 415usuarios de gimnasios sevillanos. Los usuarios fueron valo­rados antropométricamente y realizaron un cuestionarioque previamente fue evaluado para conocer la validez delcontenido, aplicación, estructura y presentación.

El 28 % de la muestra consumían o habían consumidoSPP, resultando, el 42,7% del total de los hombres frenteal 3,2% del total de las mujeres encuestadas. El porcen­taje de consumo de SPP está por encima de los valoresaportados por otros estudios que evalúan la suplementa­ción en gimnasios, 28% vs 10-14% aprox.

El consumo de SPP está asociado con el sexo, la edad yel tiempo de práctica deportiva.

Más de una cuarta parte de las personas que acudenregularmente a un gimnasio consumen SPP. El total delos usuarios de un gimnasio que consumen SPP realizanun consumo diario de proteínas mucho mayor que elrecomendado para la población normal y/o deportista,pudiendo ocasionar problemas de salud.

(Nutr Hosp. 2011;26:1168-1174)

DOI:I0.330S/nh.2011.26.S.S110Palabras clave: Ejercicio. Actividad física. Suplemento

proteico en polvo. Gimnasio. Cuestionario.

PPS: Protein Powder Supplements.CDR: Cantidad diaria recomendada.RDA: Recommended daily a11owance.IRB: Institutional review boar approval.

Introduction

The fitness center is a place where people who don'thave a professional relationship with sports train. Theenvironment created in these centers contributes tospread stereotypes and aesthetic procedures.'

In a11 areas of sport and physical activity there aremany products that look for better endurance, quickerrecovery, fat loss and muscle building. These products

also pretend to enhance sports performance and phys­ical appearance.'

Nowadays, the abuse of Sports Nutritional Supple­ments by exercising individuals that regularly attend agym has increased. These individuals look for physicalor appearance benefits without considering negativehealth consequences."

The American Dietetic Association, Dietitians ofCanada, and the American Co11egeof Sports Medicine'state that only those persons who restrict their energyintake, use severe weight-loss practices, eliminate oneor more food groups from their diets, or consume high­carbohydrate diets and low micronutrient density mayrequire sorne dietary supplementation.'

Sports Nutritional Supplements include Powder ProteinSupplements (PPS) which are products with a strongmarket position and one of the most consumed supple­ments among exercising individuals attending a gym.'According to Applegate and Grivetti' and Ciocca," proteinmay be the most nutritional ergogenic resource used.

Milo of Croton was a 6'" century B.C. famous wrestler,and winner of five gold medals in the Olympic Games inthe Ancient Greece. He trained doing laps in the stadiumand carrying a calf on his shoulders that he used to eatafter training being his meat consumption about 20 lbs.','per day. Protein sources started to become significantlyassociated with improved strength and/or musclemass. IO

, 11 Since then, the association between proteinintake and body mass has been a requirement" that hasnot been scientifica11yproven."-" Although amino acidsand proteins are essential for the synthesis of severalbody structures and are involved in many metabolicmechanisms, their intake without a we11-conductedexer­cise regimen is not enough to increase body mass andstrength. It has been suggested that athletes need extraprotein in their diet as food or as supplements.?":" butindividuals who regularly exercise in gyms do not needthis extra protein. Therefore, protein requirements mayrangefromtheno=all,Og·kg '·d 'upt02,Og·kg '·d,1 in special situations.w-'v-"

Protein and amino acids abuse, as food or supple­ments, seems to be associated with side effects such asketosis, increased body fat, gout, kidney overload,dehydration, urinary excretion of calcium, and loss ofbone mass. 12,17,19,20

Numerous studies have focused on the use of proteinsupplements in normal or pathological situations":" andby athletes of different performance levels. IO,14,15,16,, 4,25

There are a few studies on NS use by individuals thatregularly attend a gym.2632 The purpose of this study is toexamine the use of protein supplements in a group of 415individuals thatregularly attend gyms in Seville, Spain andcontribute to the existing literature about this population.

Material and methods

415 individuals (260 men and 155 women) thatregularly attend 4 gyms in Sevi11e were evaluated with

anthropometric measurements (size and weight) usinga GPM anthropometer (± 1 mm precision) and a Tefalbrand scale (± 100 g precision).

Individuals completed a questionnaire previouslyreviewed and tested in a pilot study conducted in a littlegroup (35 users) and a final version was developed. Itwas reviewed content (to observe the ability of thequestionnaire to measure the use of protein supple­ments), application (to analyze advantages and disad­vantages and to review questionnaire instructions),format (to review the formulation of questions,proposed sequence and response scale); and presenta­tion (to identify the best format and appearance for thequestionnaire) .

The questionnaire had four parts: 1) personal andanthropometric data, 2) diet and physical activity, 3)use of protein supplements, 4) legal consumption ofsupplements and negative health consequences.

For a 95% confidence (with a margin of error of5%), a minimum of 385 questionnaires were required."We selected a random sample, by giving a question­naire to every third person who carne in the door, torepresent exercising individuals' diversity. Partici­pants completed anonymous questionnaires in the gymentry. Data were co11ectedfrom 8 am to 2 pm, and from4 pm to 9 pm Monday through Friday, and from 9 am to1 pm Saturdays and Sundays. Data collection wassimultaneously conducted in just one phase and bythree po11sters during a week in three different fitnesscentres. It was our intention to cover a11 the businesshours in order to include a11 the "user pro files" .

Inforrned consent was obtained from each partici­pant. The study was exempt from institutional reviewboar approval (IRB) due to prior IRB approval fordoctoral thesis. Data analysis was carried out usingSPSS 12 (SPSS Inc. Chicago, IL, USA). First, descrip­tive statistics were performed utilizing frequencytables and percentages for categorical variables, anddescriptive measures were calculated for quantitativevariables. Then, inferential statistics were performedusing Pearson Chi-square statistic test and/or Fisherexact test for categorical variables. Previous Shapiro­Wilk or Kolmogorov-Smirnov Normality tests, T-testsand ANOVA were used to compare two or more meansof quantitative normal variables. Open-ended ques­tions were tabulated using multiple choice options."

A multivariate logistic regression analysis was usedto determine the variables that influence PPS consump­tion and consumcr's profile. The percentage of rightclassification, coefficients of corresponding exponen­tials and a 95% confidence interval were obtained.

Results

Subjects ' characteristics, anthropometrics' charac­teristics and gym practice are shown in table I and Il.

Forty-eight percent of the participants indicated thatthe main reason to attend the gym is to be in good

Prevalence of protein supplementuseat gyms

Nutr Hosp, 2011;26(5):1168-1174 1169

Table 1Sex, profession. and number of school years

Frequency 'le

SexMale 260 62.7Female 155 37.3

Student 115 27.7

ProjessionWorker 251 60.5Student andworker 41 9.9N/A 8 1.9

Primary school 63 15.2

Number ofSchool yearsHighschool 129 31.1College 127 30.6University 96 23.1

shape. The second reason is to exercise (19%), and thethird reason is for health benefits (11.1 %) (participantscould also choose more than one option). Regardinggender, male participants indicated that reasons indecreasing order of importance are: to be in goodshape, exercising and to feel better. Female partici­pants indicated these reasons for attending the gym: tobe in good shape, health benefits, and exercising.

30.1% ofthe participants in the sample (125 individ­uals, 53 males and 72 women) were on a diet thatinvolved food and nutritional control. A total of 85respondents were on a low fat diet, the most commondiet among participants.

28.0% of the total, 42.7% men and 3.2% women wereusing or used protein supplements. There are individual sthat have consumed up to 20 different PPS cornmercialbrands. Table III shows the most widely consumedcommercial brands of protein supplements by the partic­ipants. The survey included the average proportion ofprotein in the PPS consumed by the participants,78.90%. These cornmercial brands recommend a dailyaverage protein intake of 57.33 g.

We studied participant's preferred places to buyprotein supplements. They frequently chose gyrns,sports and nutrition supplements stores and shoppingmalls to buy PPS. A total of 68.1 % of the consumers

occasionally bought PPS in a gym, 51.7% occasionallybought PPS in sports and nutrition supplements storesand 14.6% in a shopping mall. Seventy-six individuals(66.1 % of the total) were motivated by friends to buyPPS, 59.7% of the total was motivated by gymsinstructors and 16.4% by trainers, although 100% ofthe gyms reported having a nutritionist.

We studied the time of day in which participantsused PPS. A total of 25 participants (21.7%) consumedproteins before training, 24 participants (20.9%)consumed them after training and 22 participants(19.1%) consumed proteins before and after training. Atotal of 22 participants (19.1 %) consumed proteins inthe morning and in the evening regardless the time oftraining. Therefore, a 52.68% of the sample used PPSonce a day, and 47.31 % twice a day. A total of 89 indi­viduals (77.4%) using PPS reported positive results, 22individuals (19.1 %) reported negative results, and 5individuals (3.7%) were undecided or did not answer.

Three-hundred-seventy-one participants (89.4%;228 men and 143 women) were in favor of legal use ofnutritional supplements. Only 16 male individuals(3.9%) from 415 total participants used or would usenutritional supplements to improve performance evenif they cause health damages. Twenty-two male indi­viduals (5.3%) used or would use illegal or prohibitedsupplements.

Logistic regression analysis (table IV) showed thatPPS use is more common among men (P = 0.0001; Ó =151.845) (the odds ratio of PPS users VS. non users is151.845 higher in our sample as shown in table IV).Men who used PPS in our sample:

- were below 30 years of age (the participants ofthestudy were divided into two groups: 30 years andbelow and aboye 30 years of age) (P = 0.007; Ó =2.499)were training in a gym for a long period of time(P = 0.0001; Ó = 1.250)attended the gym a few hours a week (P = 0.0001;Ó = 1.291) (men who spent more time in the gymwere more likely to use PPS)were on anykind of diet (P = 0.0001; Ó = 4.482)

Table 11Purticipants' age, height, body weight, and years, days of the week and time attending the gym

Age(years)'

Heightún)'

Weighl(kg)"

Yearsattending thegym-

Daysal'theweekattending!hegym:

Timeattendingthegymper day(min)b

Total

31.63± 11.15(17:68)

1.72±0.08 (1.50:1.96)

73.38± 11.26(46:112)

3.01±2.89(0.08:16)

3.64± 1.02(1:6)

87.41± 27.14(30:240)

Male

29.95± 10.22(18:68)

1.77± 0.06(1.58:1.96)

79.15±7.41(60:112)

3.13± 2.82(0.1:16)

3.78± 1.02(1:16)

92.17±25.02(45:21O)

Female

34,43± 12,06(17:65)

1,64±0,06(1,50:1,78)

63,69± 9,90(46:110)

2,82±3,0l (0,8:16)

3,41±0,97(2:6)

79,42±28,71(17:240)

Average± SD(min;max).-Highly significant (1'<0,001).''Not signiticant.Student' st testlarindependent samples was used tocompare means

1170 Nutr Hosp, 2011;26(5):1168-1174 A. Sánchez Oliver el al.

Table 111Commercial brands ofthe mostfrequently consumed protein supplements by the participants

Brand N.o ojparticipants Protein: Protein Source"

1 33 75 WPC

2 32 86 WPC

3 31 77.5 WPC

4 28 86.2 WPC

5 20 68 WPC + Calcium Caseinate

6 18 84 WPC

7 16 70.2 WPC +WPI + Partially hydrolyzed Whey Protein

8 15 85 WPC +WPI + Isolated Soy Protein

9 14 91 WPI

10 11 78 WPC

11 9 78.5 WPI +WPC +Whey Peptides

12 9 79.1 WPC + immunoglobulins

13 7 80 WPI

14 6 74.1 WPC +WPI + lactalbumin

15 5 51.7 WPC + Calcium Caseinate

16 5 87 WPC

"Dataare expressed as g/IDO g product.'Protein Source: WPC. whey protein concentrate; WPI. whey protein isolate.

The percentage of right classification was 83.6%.Table IV shows the variables (mentioned aboye) usedfor the logistic regression analysis, significance (Sig.),odds ratios (Ó) and the 95% confidence interval (el).

Discussion

There are several articles in current bibliographythat evaluate SN consumption in fitness centers.Among thern, there are several about PPS consump­tion, the object of our study. The percentage of PPSused in our study (28%) is higher than what has been

reported in previous studies (10% and 13,98%) thatevaluated SN consume by fitness center ' s user. 26.27

Consistent with previous reports, PPS consumptionwas more prevalent among men. 26

.30

As in our study, to be in form, to do exercise or to behealthy are sorne of the options most chosen to come tothe gymnasium.>"

The results found in the bibliographical reviewregarding who informs and promotes SPP consump­tion are similar to our study results." Mainly, the usersreported taking supplements by suggestion from africnd.>? self-prescription26,27,30,35 and trainer or gym' sinstructor indications, 2629,363R and their supplements use

Table IVConsumer profile variables to be considered in nutritional supplements users

95% el

Riskvariables B Wald Sig.(P) OR lnferior Superior

Sex'" 5.023 51.565 0.000 151.845 38.548 598.130

Age> 0.223 15.299 0.007 2.499 1.278 4.888

Time (1) 0.255 19.760 0.000 1.250 1.118 1.398Diet(4) 1.500 14.721 0.000 4.482 2.083 9.643

Hours/week'" 0.916 7.162 0.000 1.291 1.153 1.445

(I)Malevs Female.(') < 30 years vs > 30 years.(.') Those who have attended the gym for a longer time consume more.(') Diet vs No Diet.(5) Those who exercise more hours consume more.

Logistic Regresion Analysis Results

Prevalence of protein supplement useat gyms

Nutr Hosp, 2011;26(5):1168-1174 1171

is wilhout seeking any professional guidance, althougha lot of the gyms reported having a nutritionist."

The percentage of SPP consumers that obtained thedesired results was higher in our study (77%) than inother reviewed studies (55%)". There is no conclusiveevidence that the majority of supplements have anyheallh or performance benefits, and any improvementrelated to performance is typically mediated byplacebo effects.v" According to the American DieteticAssociation, Dietitians of Canada, and the AmericanCollege of Sports Medicine when alhletes believe thatcertain foods, diets or supplements improve perfor­mance, these substances or technologies can pro videpsychological benefits, more than physiological enes."Short (1994) and Trissler (1999) have verified in theirstudies that sorne consumers buy SN just in case theyare useful. 12,40

Many checked studies, included ours, associatedsupplement use with a sex, age, and time of sport prac­ticed. Thus, young men, who go to fitness center regu­larly (3 times at the week) since 1 year ago at least, isthe pro file of thc consumer of SN. ",27,31,32 The fact thatthe majority of SPP consumers have been exercisingregularly for more than ayear shows that there is atendency to look for supplements in order to improveresults. Time devoted to exercise and attending thefitness center affects supplement use as individuals aremore exposed to a consumption environment.

The partici pants preferred gyms, sport s and nutritionsupplements stores, and shopping malls to buy PPS.There is only anolher study that reports athletes' pref­erences to buy PPS:41 superrnarkets, sports and nutri­tion supplements stores, and pharmacies. We observethat sports and nutrition supplements stores are theonly places in common preferred by users in bothstudies.

According to scientific literature,"-" the recom­mended daily intake of protein varies from 1.2 to lAg/kg for resistance athletes, and from 1.7 to1.8 g/kg forstrenglh athletes- it is 160% and 220% of the recom­mended intake for general population (0.8 g/kg/day)."

The indirect assessment of total energy expenditureof PPS users (considering basal metabolic rate, diet­induced lhermogenesis and the energy cost of physicalactivity ":" report a mean energy expenditure of 3251kcal/day for men (we have chosen male participantsbecause they are more representative). The recom­mended protein intake is 15% of total energy intake(488 kcal), it is 122 g/kg/day for meno Participants inour study add one or two intakes of57.33 g ofPPS witha protein purity of 78.9% (45.23g in one or twointakes). This results in the consumption of 167 g to212 g/kg/day of protein by male participants in one ortwo intakes. Considering that the average weight ofmale PPS users is 76.52 kg, we have found that theyconsume from 2.2 g to 2.8 g/kg/day of protein, approxi­mately 309% of the daily recornmended allowance forgeneral population, 44 190% for resistance athletes and141 % of the recommended protein allowance for

strenglh alhletes. Obviously, this high intake of proteinfar exceeds the daily recommended allowance for thethree groups. Very rarely, those individuals who exer­cise regularly should take dietary supplements. 7,4751

The abuse of protein supplements increases the risk ofdehydration if thc right amount ofliquid is not consumedbecause 50 ml of water are needed to excrete a gram ofurea. 43 The exceed consumption of proteins can catalyzedeanimation and transamination processes and thc trans­formation of hydrocarbonated residues in fat, as there arenot amino acids reserves in the body.' Furthermore, thehigh intake rate of protein by thc participants might indi­cate inappropriate and dangerous consumption. Theamino acid carbon skeleton may be deviated by energyproduction (Krebs cycle intermediary compoundsynthesis) or excreted, because the human being doesnot have a protein reserve compartment.

8904% ofthe participants in the sample were in favorof legal use of nutritional supplements. Only 3.9% ofthe participants would use supplements even if theycause heallh damages, and 5.3% would use illegal orprohibited supplements. Numerous studies have shownthat supplement users are not conscious of the productsthey consume and sometimes they use supplementsthat are harmful and/or contain illegal or prohibitedsubstanccs.v'v"" The majority of these studies havefound that many users do not receive professionalinformation about nutritional supplements. The mediaplay an important role in the decision to use supple­ments.vv' The population is increasingly exposed tomore information from the media than from the scien­tific community.v"

PPS have been bought for many years by strenglhathletes aboye all. PPS protein content is derived fromcow's milk, eggs and soy and does not add any advan­tage to natural sources when equivalent amount ofproteins are compared. Purthermore, PPS are moreexpensive than natural sources of protein. This is basedon the mistaken idea that protein supplements havespecial muscle-building power or, which is evenworse, that unlimited muscle mass and strength areassociated with a higher consumption of proteins." Itmust be highlighted that even if these supplements areuseful to provide additional protein sources, they mustbe a complement to a well-balanced healthy diet not asubstitute. Conclusive results show that the averageWestern diet provides enough protein for athletes."More education is needed about NS and PPS risks andeffective use and, more importantly, how to maximizenutrient intake from food to minimize or avoid the useof nutritional supplements."

According to the American Dietetic Association"any recommendation for alhletes and sportsmen/women should be given based on current scientific dataand individual needs.

Supplements should be used cautiously and onlyafter checking that they are legal. The existing litera­ture about the ingredients on the product label shouldbe reviewed. Supplements should not be recommended

1172 Nutr Hosp, 2011;26(5):1168-1174 A. Sánchez Oliver et al.

without evaluating the individual's health, diet, nutri­tional and energetic needs, and current use of supple­ments and drugs.

Conclusions

In conclusion, a considerable number of people whoregularly exercise at gyms consume PPS, mostlywithout specialized guidance and possibly without realneed of them. Men who attend a gym consume morePPS than women. Men who are below 30 years of ageand on any kind of diet consume more PPS.

The total number of individuals attending a gym thatuse PPS exceed the recommended intake of proteinsfor general population ancl/or athletes. Overuse of PPSto be associated with health risk. 12,17,19,20

One can conclude that the use of supplements wasassociated with people who perhaps needed them less.

Supplements use in fitness centres is sufficientlyrelevant and important to receive attention in futuredetailed studies.

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