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Cited by 184Nutrition and Health StudiesComplementary and Alternative Medicine StudiesDoping in Sports

Intake of nutritional supplements among people exercising in gyms and influencing factors

Open access
Goston, Janaina Lavalli, Toulson Davisson Correia, Maria Isabel·2010·Nutrition
DOI 10.1016/j.nut.2009.06.021
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Abstract

Objective To assess supplement intake in people who exercise regularly in gyms in the city of Belo Horizonte, Brazil, and discuss the influencing factors on its ingestion. Methods A total of 1102 enrolled subjects who exercised in 50 gyms throughout the city were part of this cross-sectional study. Men and women were recruited and all subjects were at least 18 y old. Participants were asked to complete written questionnaires about their use of supplements. Data were collected over a period of 4 mo. Descriptive statistics and chi-square tests were performed. Results The intake of nutritional supplements was reported by 36.8% of participants. The highest intake was in men (44.6%). Five products were consumed almost daily: those rich in proteins and amino acids (58%), isotonic drinks (32%), those rich in carbohydrates (23%), natural/phytotherapeutic (20%), and multivitamin/mineral supplements (19%). Most people (55%) reported using nutritional supplements without any specialized professional guidance and based primarily on self-prescription. Individuals younger than 30 y, mainly men (odds ratio 3.28, 95% confidence interval 2.06-5.20, P Conclusion Our results show that supplement intake in people exercising in gyms is high and is usually self-prescribed. We emphasize that the use of dietary supplements must be always done under the supervision of a specialist (physician or nutritionist).

AI snapshot

Written from the paper’s full text.

TL;DR

In a cross-sectional survey of 1,102 adults exercising in 50 gyms in Belo Horizonte, Brazil, 36.8% reported using nutritional supplements, most often without professional guidance. Use was higher among men and younger participants, especially for protein- and amino-acid-rich products, while older participants more often used multivitamins/minerals and natural or phytotherapeutic supplements.

Key findings

  • Supplement use was reported by 36.8% of participants; men reported higher use than women (44.6% vs 28.1%, P < 0.01).
  • Protein- and amino-acid-rich supplements were the most commonly consumed category (58% of users), followed by isotonic drinks (32%), carbohydrate-rich products (23%), natural/phytotherapeutic agents (20%), and multivitamin/mineral supplements (19%).
  • Most users (55%) took supplements without specialized professional guidance, relying on self-prescription, friends, store staff, or advertising.
  • Younger participants, especially men, were more likely to use protein-rich supplements (men vs women OR 3.28, 95% CI 2.06–5.20; age <30 vs >45 OR 2.73, 95% CI 1.26–5.94), while older participants more often used multivitamins/minerals and natural/phytotherapeutic products (OR 5.52, 95% CI 2.76–11.06).

Methods

  • Cross-sectional study conducted in 50 randomly selected gyms in Belo Horizonte, Brazil, with 1,102 participants aged 18 years or older who exercised at least twice weekly.
  • Data were collected over 4 months using a self-administered questionnaire covering demographics, lifestyle, supplement type and frequency, reasons for use, and information sources.
  • Analyses used descriptive statistics, chi-square tests, and odds ratios in SPSS 10.0, with significance set at P < 0.05.

Limitations

  • The paper does not include a formal limitations section; it explicitly notes that the study did not measure the amount of protein intake.
  • Evident from the text: supplement use and related behaviors relied on self-report, which the authors note may lead to under- or over-reporting.
  • Evident from the text: the cross-sectional design cannot establish causality, and the sample came from gyms in one Brazilian city and was largely college-educated, limiting generalizability.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1016/j.nut.2009.06.021

Cites

83 of 83 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

5 of 33 cited sources checked · 2 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    The population is increasingly exposed to more information from the media than from the scientific community.

    “The population is increasingly exposed to more information from the media than from the scientific community [31,65,69].”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites [31] Conner, 2003, Environmental influences: factors influencing a woman's decision to use dietary supplements, J Nutr source

      The discussion of normative beliefs (p. 1980S) suggests that books and magazines may influence women's decisions about dietary supplements. It does not measure information exposure, compare media with the scientific community as sources of information, or establish an increasing trend. Searches for those comparisons found no supporting passage in our copy. (LLM, conf=0.75)

      Experimental — accuracy not yet measured
    • cites [65] Winterstein, 2001, Herbal supplements: considerations for the athletic trainer, J Athl Train
    • cites [69] Pipe, 2002, Nutritional supplements and doping, Clin J Sport Med source
  • Premisecitation

    The media play an important role in the decision to use supplements.

    “The media play an important role in the decision to use supplements [39,68].”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [39] Scofield, 2006, Dietary supplement use among adolescent athletes in central Nebraska and their sources of information, J Strength Cond Res source
    • cites [68] Chung, 2007, Evaluation of non-English dietary supplement advertisements in an ethnic minority community in America, Public Health Nutr source

      The Conclusion says non-English supplement advertisements in an ethnic minority community “may be influencing consumer decisions,” and the Discussion describes their potential impact. This supports a possible role for media, but the citing sentence states a definite, general role in decisions to use supplements that this paper does not establish. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
  • Findingown data

    Natural and phytotherapeutic agents, multivitamins and minerals, and meal-replacement products were mostly taken by women (P < 0.01).

    “Natural and phytotherapeutic agents, multivitamins and minerals, and meal-replacement products were mostly taken by women (P < 0.01; Table 4).”
    Quote in the paperNot a substantial claim
  • Findingown data

    The intake of nutritional supplements was reported by 36.8% of participants.

    “The intake of nutritional supplements was reported by 36.8% of participants, as shown in Figure 2.”
    Quote in the paperNot a substantial claim
  • Findingown data

    Individuals who exercised longer than 1 y had an odds ratio of 2.00 (95% CI 1.33-3.02) for consuming nutritional supplements compared with those exercising for shorter periods (P < 0.01).

    “Thus, individuals who exercised longer than 1 y presented with an odds ratio (OR) of 2.00 (95%confidence interval [CI] 1.33-3.02)for consuming nutritional supplements compared with the group that had been exercising for shorter periods (P < 0.01; Table 1).”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. 17
  • May combine two claims. 11
  • The quote only partly states this claim. 2

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The use of supplements has greatly increased in the past 10 y.

    “Despite this recommendation, the use of supplements has greatly increased in the past 10 y [12].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [12] Harrison, 2004, Are those in need taking dietary supplements? A survey of 21 923 adults, Br J Nutr source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The desire for achieving quick results has made the use of such substances very attractive.

    “The desire for achieving quick results has made the use of such substances very attractive [7].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [7] Rocha, 1998, Consumo de suplementos nutricionais por praticantes de exercícios físicos em academias, Rev Nutr source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The amount of money spent by the study participants on dietary supplements was not considered to be excessive.

    “The amount of money spent by the study participants on dietary supplements was not considered to be excessive [21,22,74].”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites [21] Hirschbruch, 2003, Consumo de suplementos por alunos de academias de ginástica em São Paulo, Rev Nutr source

      The Results report participants’ monthly spending on supplements (p. 269), and the Discussion says men spent more than women. Neither passage assesses whether the spending was excessive, so the cited paper does not support that characterization. (LLM, conf=0.81)

      Experimental — accuracy not yet measured
    • cites [22] Slater, 2003, Dietary supplementation practices of Sigaporean athletes, Int J Sport Nutr Exerc Metab source
    • cites [74] Tian, 2009, Nutritional supplement use among university athletes in Singapore, Singapore Med J

  • May combine two claims.

    Findingown data

    Users reported taking supplements by self-prescription, suggestion from a friend or a clerk in a store, or under the influence of advertisements.

    “The users reported taking supplements by self-prescription, suggestion from a friend or a clerk in a store, or under the influence of advertisements (Fig. 4).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The level of education did not influence the amount of money spent on supplements or on the decision to use them (P < 0.01).

    “The level of education did not influence the amount of money spent on supplements or on the decision to use them (P < 0.01).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Other reported reasons for supplement use included improving performance (22.7%), losing weight (21.7%), covering nutritional deficiencies (16.3%), decreasing stress (15.3%), and preventing future diseases (8.6%).

    “Other reasons included to improve performance (22.7%), to lose weight (21.7%), to cover for nutritional deficiencies (16.3%), to decrease stress (15.3%), and to prevent future diseases (8.6%).”
    Quote in the paperNot a substantial claim

  • The quote only partly states this claim.

    Findingown data

    Men had higher odds of using creatine than women (P<0.01; 12.8% vs 0%).

    “Percentage (n) | 12.8 (33) | 0 | 11.5 (27) | 4.8 (6) | 0 |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Among supplement users, isotonic drinks were taken regularly by 12.6%.

    “Isotonic drinks | 12.6 (16) | 49.6 (63) | 37.0 (47) |”
    Quote in the paperNot a substantial claim

  • The quote only partly states this claim.

    Findingown data

    Among supplement users, multivitamins and minerals were the most regularly used supplement, with 75.3% taking them regularly.

    “Multivitamins and minerals 75.3 (61) | 22.2 (18) | 2.5 (2) |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Athletes have been the greatest consumers of many nutritional supplements.

    “Athletes have been the greatest consumers of many of these products [1][2][3] and their habits may be followed by other groups of individuals [4,5], mainly those who exercise in gyms regularly [6].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [1] Burke, 2006, Supplements and sports foods
    • cites [2] Erdman, 2006, Influence of performance level on dietary supplementation in elite Canadian athletes, Med Sci Sports Exerc source
    • cites [3] Huang, 2006, The use of dietary supplements and medications by Canadian athletes at the Atlanta and Sydney Olympic Games, Clin J Sport Med source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Only those persons who restrict their energy intake, use severe weight-loss practices, eliminate one or more food groups from their diets, or consume high-carbohydrate diets and low micronutrient density may require some dietary supplementation.

    “The American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine [11] state that only those persons who restrict their energy intake, use severe weight-loss practices, eliminate one or more food groups from their diets, or consume high-carbohydrate diets and low micronutrient density may require some dietary supplementation [3].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [11] 2000, Dietitians of Canada, American College of Sports Medicine. Nutrition and athletic performance, J Am Diet Assoc source
    • cites [3] Huang, 2006, The use of dietary supplements and medications by Canadian athletes at the Atlanta and Sydney Olympic Games, Clin J Sport Med source

  • May combine two claims.

    Interpretationown data

    Supplement intake in people exercising in gyms is high and is usually self-prescribed.

    “Our results show that supplement intake in people exercising in gyms is high and is usually self-prescribed.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    In general, physically active people do not need additional nutrients apart from those obtained from a balanced diet.

    “However, it is known that, in general, physically active people do not need additional nutrients apart from those obtained from a balanced diet [8][9][10].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [8] Rockwell, 2001, Nutrition knowledge, opinions, and practices of coaches and athletic trainers at a division I university, Int J Sport Nutr Exerc Metab source
    • cites [9] Costill, 2003, Nutrição: a base para o desempenho humano

      Not checked in the free run.

    • cites [10] Silva, 2005, Guia alimentar para atletas

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Some supplements contain excessive doses of potentially toxic ingredients, whereas others do not contain significant amounts of the ingredients listed on the label.

    “Some supplements contain excessive doses of potentially toxic ingredients, whereas others do not contain significant amounts of the ingredients listed on the label [13,14].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [13] Maughan, 2005, Contamination of dietary supplements and positive drug tests in sport, J Sports Sci source
    • cites [14] Di Luigi, 2008, Supplements and the endocrine system in athletes, Sports Med source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Among athletes and physically active individuals, an increased intake of substances forbidden by the International Olympic Committee/World Anti-Doping Agency, many of these the so-called prohormones, has been observed.

    “Furthermore, among athletes and physically active individuals, an increased intake of substances forbidden by the International Olympic Committee/ World Anti-Doping Agency, many of these the so-called prohormones, has been observed [13].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [13] Maughan, 2005, Contamination of dietary supplements and positive drug tests in sport, J Sports Sci source

  • May combine two claims.

    Interpretationown data

    A considerable number of people who regularly exercise at gyms consume dietary supplements, mostly without specialized guidance and possibly without real need of them.

    “In conclusion, a considerable number of people who regularly exercise at gyms consume dietary supplements, mostly without specialized guidance and possibly without real need of them.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Kamber et al. analyzed 75 products used as sports supplements and found that some supplements contained caffeine and ephedrine and that the compounds were either not declared or not clearly declared on the labels.

    “Kamber et al. [29] analyzed 75 products used as sports supplements and found that some supplements contained caffeine and ephedrine and that the compounds were ''either not [declared] or not clearly declared on the labels.''”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [29] Kamber, 2001, Nutritional supplements as a source for positive doping cases?, Int J Sport Nutr Exerc Metab source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The study protocol was approved by the Federal University of Minas Gerais research ethics committee under number 097/07.

    “The study protocol was approved by the Federal University of Minas Gerais research ethics committee under number 097/07.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductown data

    A total of 183 active gyms were identified in the city, and approximately 25% were selected to compose a stratified random sampling by region, resulting in 50 gyms included.

    “A total of 183 active gyms were identified in the city.Of these, approximately 25% were selected to compose a stratified random sampling by region.Thus, 50 gyms were included in this study.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    Only gyms that offered several sports activities were included to avoid the selection of participants who mainly did body-building activities.

    “In addition, only gyms that offered several sports activities were included to avoid the selection of participants who mainly did body-building activities.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Each questionnaire was verified by one of the researchers with the participant to check inconsistencies in responses and avoid incomplete data.

    “After completion, each questionnaire was verified by one of the researchers (J.L.G.) with the participant, to check inconsistencies in responses and therefore avoid incomplete data.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    The sample size (n=1102) was calculated based on an estimated proportion of supplement users of 50%, a 95% confidence level, and a 3% margin of error.

    “The sample size calculation (n ¼ 1102) was based on the equation n ¼ b p$ð1Àb pÞ$z 2 e 2 where b p was the estimated proportion of individuals who use supplements (50%), z the normal distribution (defined as 1.96 for research with 95% confidence), and e the study margin of error (3%).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Supplements that provide essential nutrients may be of help when food intake or food choices are restricted, which seems not to be the case in most individuals exercising regularly in gyms.

    “Supplements that provide essential nutrients may be of help when food intake or food choices are restricted, which seems not to be the case in most individuals exercising regularly in gyms.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    The survey questionnaire was previously tested in a pilot study conducted in two gyms in different regions of the city and a final version was developed.

    “This questionnaire was previously tested in a pilot study conducted in two gyms in different regions of the city and a final version was developed.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Those who practice body-building consume more nutritional supplements than other sports participants.

    “It is known that those who practice this activity consume more nutritional supplements than other sports participants [4,6,24,30].”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [4] Sobal, 1994, Vitamin/mineral supplement use among high school athletes, Adolescence

      Not checked in the free run.

    • cites [6] Morrison, 2004, Prevalent use of dietary supplements among people who exercise at a commercial gym, Int J Sport Nutr Exerc Metab source
    • cites [24] Erdman, 2007, Dietary supplementation of high-performance Canadian athletes by age gender, Clin J Sport Med source
    • cites [30] Gibala, 2000, Nutritional supplementation and resistance exercise: what is the evidence for enhanced skeletal muscle hypertrophy?, Can J Appl Physiol source
25 of 25

  • The paper relies on this without support.

    Little is known about supplement intake among people exercising in gyms.

    “However, little is known about supplement intake among people exercising in gyms.”

  • The paper relies on this without support.

    Intake of amino acids and proteins without a well-conducted exercise regimen is not enough to increase body mass and strength.

    “Although amino acids and proteins are essential for the synthesis of several body structures and are involved in many metabolic mechanisms, their intake without a well-conducted exercise regimen is not enough to increase body mass and strength.”

  • The paper relies on this without support.

    There are very few scientific studies that support the believed benefits of these nutrients.

    “However, there are very few scientific studies that support these believed benefits.”

  • The paper relies on this without support.

    The human being does not have a protein reserve compartment.

    “because the human being does not have a protein reserve compartment.”
4 of 4

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Overall mean age is below both subgroup means

    Major

    Supplement users and non-users together make up the participants. An overall mean of 29 years cannot result when their reported mean ages are 31 and 33 years.

  • Abstract treats overall use as near-daily use

    Minor

    The abstract describes isotonic drinks at 32% as among products consumed almost daily. Table 2 reports regular isotonic-drink intake for only 12.6% of those taking that product; 32% is not its regular-intake frequency.

  • Table 1 age categories overlap

    Minor

    Table 1 lists a reference group labeled "<45" alongside groups aged 30-45 and <30. Those cannot be distinct age categories; elsewhere the oldest group is labeled >45.

  • Education P value conflicts with Table 1

    Minor

    The discussion gives P < 0.01 while saying education did not affect the decision to use supplements. Table 1 instead reports P = 0.30 for education and supplement use.

  • Meal-replacement significance differs from Table 4

    Minor

    The text assigns P < 0.01 to the listed supplements taken mostly by women, including meal-replacement products. Table 4 gives P = 0.02 for meal-replacement products.

5 of 5

Cites

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Related

Authors
Goston, J. L., & Toulson Davisson Correia, M. I.
Venue
Nutrition
Publisher
Elsevier BV
Published
2010-06
Volume
26
Issue
6
Pages
604-611
ISSN
0899-9007 (ISSN-L)
DOI
10.1016/j.nut.2009.06.021
OpenAlex
W2031907691
Semantic Scholar
6cff5aa5080c9065d2062b7e4381e76d24e182a3
Cited by
184
References
92
Citations by year
2026: 4 · 2025: 4 · 2024: 13 · 2023: 17 · 2022: 15 · 2021: 15 · 2020: 12 · 2019: 10 · 2018: 15 · 2017: 13 · 2016: 13 · 2015: 17 · 2014: 11 · 2013: 6 · 2012: 5
FWCI
6.36
Type
journal article
Language
en
Open access
Licence
Locations
  • Nutrition (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Health Sciences › Medicine › Public Health, Environmental and Occupational Health › Nutrition and Health Studies
  • Health Sciences › Medicine › Complementary and alternative medicine › Complementary and Alternative Medicine Studies
  • Social Sciences › Sociology and Political Science › Doping in Sports
Keywords
dietary supplements, supplement use, gym exercise, self-prescription, protein supplements, isotonic drinks, multivitamin and mineral supplements, phytotherapeutic agents, age differences, sex differences, professional guidance, Belo Horizonte
MeSH terms
Adolescent, Adult, Age Factors, Aged, Aged, 80 and over, Biological Products, Brazil, Cross-Sectional Studies, Diet Surveys, Dietary Carbohydrates, Dietary Proteins, Female, Humans, Male, Phytotherapy, Middle Aged, Surveys and Questionnaires, Self Care, Sex Factors, Health Behavior, Exercise, Odds Ratio, Micronutrients, Dietary Supplements, Young Adult

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