The use of nutritional supplements among exercisers in gyms has been never investigated in the Middle East. The aim of the current study was to assess the prevalence intake of nutritional supplements and the potential influencing factors among people exercising in gyms in Beirut city. In this cross-sectional study, 512 exercisers, aged between 20 and 50 years, were randomly selected from gyms. The intake of nutritional supplements was reported among 36.3% (95% confidence interval 32.2–40.5) of participants, with a weak presence of medical supervision. Patterns of supplement use differed by gender and age. Men and younger exercisers were found to focus on supplements associated with performance enhancement and muscle building, while women and older exercisers were more concerned with health-promoting products such as vitamins, minerals, and herbal supplements. An appropriate dissemination of accurate and scientifically sound information regarding the benefits and side effects of nutritional supplements is highly recommended in the sports environment in Beirut city.
Lebanon is a Mediterranean country with an estimated population of about 4 million, of which 40% lives in the capital Beirut. Lebanon has been regarded as a country in transition, experiencing a shift in disease type and prevalence as well as in lifestyle and dietary habits [
Nutritional supplements are food components, for example protein, and not foods, or pharmaceutical preparations, for example vitamins and minerals capsule or tablet, supplying one or more nutrients in a concentrated form including proteins, minerals, vitamins, trace elements, and other components that are theoretically present in a normal and balanced diet [
There is enough evidence that physically active people do not require additional nutrients apart from those obtained from a balanced diet [
Despite these recommendations, the use of supplements has greatly increased in the past years [
Apart from elite sports club, the highest density of supplement users may reside in the gyms. People exercising in gyms may represent a major target for the supplement market due to their increased widespread existence and to the ease of their access to a variety of sports foods and nutritional supplements. However, limited number of studies described the prevalence of supplement use among people exercising in gyms [
The increase in demand for nutritional supplements was attributed to various reasons, including enhancing performance, improving health, preventing nutritional deficiencies and illness, increasing muscle mass, decreasing body fat, boosting immunity, increasing alertness and mental activity, improving recovery, and reducing stress [
The practices of athletes and exercising individuals in the Middle East region, and more specifically in Lebanon, remain undocumented. Thus, this study aimed to assess the prevalence of nutritional supplements’ intake among people who exercise in gyms in the city of Beirut, and to discuss the potential influencing factors as well as the major sources of information and motives associated with their use in an effort to tailor the adequate nutritional awareness campaigns targeted towards exercisers themselves as well as people influencing their decisions.
This was a cross-sectional study carried out in the city of Beirut, Lebanon, from June 2010 to August 2010.
The sample size calculation (
A two-stage sampling was performed. In the first stage, all commercial gyms were identified based on the address listings provided by various public and information agencies in the city of Beirut. Gyms that reported offering only one type of physical activity were excluded from the study. Telephone contacts were carried out in order to assess their current existence and activities. In the second phase, a systematic random scheme was used in order to select adults from the eligible gyms (
The study was conducted according to the principles expressed in the Helsinki Declaration and was approved by the Institutional Review Board of the American University of Beirut, Lebanon.
The administered questionnaire consisted of 17 questions, divided into three main parts. The first part included questions concerning demographic characteristics such as age, gender, educational background, disease history, alcohol consumption, and smoking status. The second part tackled sports-related features, such as type, frequency, and total duration of physical activities. The third part of the questionnaire consisted of questions related to supplement use. In this section of the questionnaire, participants had to mention about the sources of sports nutrition information, the motivations for the use of nutritional supplements, as well as the types of supplements being used and the duration and timing of their consumption. This questionnaire was previously tested in a pilot study conducted in gyms from two different regions of the city of Beirut, and a final version was developed. All surveys were filled by the researchers themselves, after reading the questions to the participants.
Statistical analyses were conducted using SPSS software (version 17.0; SPSS, Chicago, Ill).
All variables were categorical. Descriptive analyses were based on frequencies and percentages. Pearson chi-square tests were used to identify associations of supplement intake status (user/nonuser) with factors potentially related to its use.
Independent two-step cluster analyses were used to motivate modality grouping within each question (types of nutritional supplements, reasons for supplement use, and sources of supplement information). This method creates groups of subjects as homogeneous as possible inside each group, and as contrasted as possible between groups. It combines sequential and hierarchical agglomerative methods preclustering and then subclustering data. The determination of the number of clusters was based on the largest relative increase in distance between the two closest clusters defined by the Schwarz Bayesian Criterion as well as on potentially meaningful explanations. The type of nutritional supplements in use was best described by the following modalities: performance supplements (aggregating creatine, amino acid pills, arginine, glutamine, and branched-chain amino acids), vitamins/minerals (including multivitamins, multiminerals, vitamin and mineral supplements, as well as vitamin C and vitamin E), weight/fat loss supplements (including carnitine, protein bars, and protein shakes), alertness/energy supplements (comprising caffeine and sports energy drinks), natural supplements (with herbal supplements, iron, calcium tablets, and fish oil pills), and the last cluster included soy and sports bar. Finally, protein powder, casein protein, whey protein, and antioxidants remained independent as they were not found to fit into any of the six clusters. Four clusters have been identified covering all reasons for supplement use among those proposed: disease prevention (prevention of nutritional deficiencies, treatment of medical problems, and prevention of diseases in the future), immunity/energy boosting (immunity boosting, increased alertness and mental activity, and decreased stress), muscle building (muscle gain or weight gain, muscle repair or recovery, strength enhancement, and performance improvement), and weight/fat loss (meal replacement, weight loss, and decreased body fat). The sources of supplement information were described by three clusters: medical/paramedical (dietitians and physicians), media (magazines, internet, media, books, and friends), and coaches (coaches and companies). These clusters have been used for subsequent analyses except otherwise stated.
Types of nutritional supplements, reasons for supplement use, and sources of supplement information were analyzed by gender and age group. Several variables were found to influence these nutritional supplements-associated parameters. Age appeared as a common variable in few studies [
Differences were considered statistically significant at
Table
Sociodemographic and lifestyle characteristics of all participants and of users of nutritional supplements. No missing data.
Percentage of total population ( | Percentage of supplement users ( | ||
---|---|---|---|
Gender | |||
Male | 60.9 | 72.0 | <0.001 |
Female | 39.1 | 28.0 | |
Age group (years) | |||
20–30 | 63.7 | 64.0 | 0.936 |
30–40 | 26.6 | 26.9 | |
40–50 | 9.8 | 9.1 | |
Education | |||
Brevet | 10.2 | 9.1 | 0.615 |
Lebanese Bachelor | 13.7 | 10.8 | |
Technical degree | 5.5 | 6.5 | |
Bachelor | 56.8 | 59.1 | |
Masters or above | 12.3 | 12.4 | |
Others | 1.6 | 2.2 | |
Alcohol intake | |||
No | 65.6 | 60.8 | 0.080 |
Yes | 34.4 | 39.2 | |
Smoking status | |||
No | 61.7 | 59.1 | 0.500 |
Current | 31.3 | 34.4 | |
Former | 7.0 | 6.5 | |
Disease history | |||
No | 92.8 | 90.3 | 0.106 |
Yes | 7.2 | 9.7 | |
Total time of exercise | |||
<1 month | 3.9 | 1.6 | 0.005 |
1–6 months | 11.5 | 10.2 | |
7 months–1 year | 9.2 | 4.8 | |
>1 year | 75.4 | 83.3 | |
Frequency of exercise | |||
<3 times/week | 16.8 | 14.0 | 0.099 |
3–5 times/week | 64.1 | 62.4 | |
>5 times/week | 19.1 | 23.7 | |
Total time of daily exercise | |||
<1 hour/day | 18.0 | 16.7 | 0.673 |
1-2 hours/day | 68.6 | 71.0 | |
>2 hours/day | 13.5 | 12.4 |
As shown in Table
Most of those interviewed exercised for more than a year (75.4%) (Table
The intake of nutritional supplements was reported by 36.3% (95% confidence interval 32.2–40.5) of participants.
Supplement use status was significantly associated with gender and total time of exercise (Table
When analyzing supplement use by types of physical activities in Table
Types of physical activities performed in the gyms by supplement users (
Types of physical activities | Percentage supplement use ( | |
---|---|---|
Strength training | ||
No | 19.4 (36) | <0.001 |
Yes | 80.6 (150) | |
Treadmill | ||
No | 43.0 (80) | 0.021 |
Yes | 57.0 (106) | |
Team sport | ||
No | 72.6 (135) | 0.265 |
Yes | 27.4 (51) | |
Water sport | ||
No | 80.6 (150) | 0.808 |
Yes | 19.4 (36) | |
Fights and Martial Arts | ||
No | 85.5 (159) | 0.019 |
Yes | 14.5 (27) | |
Yoga | ||
No | 94.1 (175) | 0.515 |
Yes | 5.9 (11) | |
Others | ||
No | 89.8 (167) | 0.389 |
Yes | 10.2 (19) |
The types of nutritional supplements consumed by participants are shown in Figure
Types of nutritional supplements used among supplement users (
Almost half of the participants (44.1%) reported using supplements for more than 2 years, while 22% described taking them for 1 to 2 years (data not shown).
As shown in Table
Types of nutritional supplements by gender and age group (
Types of nutritional supplements | Gender | Age group (years) | |||
Men | Women | 20 | 30 | 40 | |
Performance supplements cluster | |||||
Percentage ( | 54.5 (73) | 1.9 (1) | 42.0 (50) | 46.0 (23) | 5.9 (1) |
Odd ratio (95% CI) | 1.000 | 0.016 (0.002 | 1.000 | 1.176 (0.605 | 0.086 (0.011 |
| <0.001 | 0.010 | |||
Vitamins/minerals cluster | |||||
Percentage ( | 23.9 (32) | 46.2 (24) | 28.6 (34) | 28.0 (14) | 47.1 (8) |
Odd ratio (95% CI) | 1.000 | 2.732 (1.392 | 1.000 | 0.972 (0.466 | 2.222 (0.792 |
| 0.003 | 0.278 | |||
Weight/fat loss supplements cluster | |||||
Percentage ( | 20.9 (28) | 5.8 (3) | 21.8 (26) | 6.0 (3) | 11.8 (2) |
Odd ratio (95% CI) | 1.000 | 0.232 (0.067 | 1.000 | 0.228 (0.066 | 0.477 (0.102 |
| 0.013 | 0.035 | |||
Alertness/energy supplements cluster | |||||
Percentage ( | 25.4 (34) | 9.6 (5) | 25.2 (30) | 14.0 (7) | 11.8 (2) |
Odd ratio (95% CI) | 1.000 | 0.313 (0.115 | 1.000 | 0.483 (0.196 | 0.396 (0.085 |
| 0.018 | 0.163 | |||
Soy and sports bar cluster | |||||
Percentage ( | 11.2 (15) | 17.3 (9) | 15.1 (18) | 8.0 (4) | 11.8 (2) |
Odd ratio (95% CI) | 1.000 | 1.660 (0.677 | 1.000 | 0.488 (0.156 | 0.748 (0.157 |
| 0.264 | 0.447 | |||
Natural supplements cluster | |||||
Percentage ( | 13.4 (18) | 63.5 (33) | 18.5 (22) | 34.0 (17) | 70.6 (12) |
Odd ratio (95% CI) | 1.000 | 11.193 (5.278 | 1.000 | 2.271 (1.077 | 10.582 (3.380 |
| <0.001 | <0.001 | |||
Protein powder | |||||
Percentage ( | 55.2 (74) | 0 (0) | 43.7 (52) | 40.0 (20) | 11.8 (2) |
Odd ratio (95% CI) | 1.000 | 0.000 | 1.000 | 0.859 (0.439 | 0.172 (0.038 |
| <0.001 | 0.042 | |||
Casein protein | |||||
Percentage ( | 3.0 (4) | 0 (0) | 2.5 (3) | 0.0 | 5.9 (1) |
Odd ratio (95% CI) | 1.000 | 0.000 | 1.000 | 0.000 | 2.417 (0.237 |
| 0.208 | 0.316 | |||
Whey protein | |||||
Percentage ( | 41.0 (55) | 9.6 (5) | 31.9 (38) | 38.0 (19) | 17.6 (3) |
Odd ratio (95% CI) | 1.000 | 0.153 (0.057 | 1.000 | 1.306 (0.656 | 0.457 (0.124 |
| <0.001 | 0.298 | |||
Antioxidants | |||||
Percentage ( | 3.0 (4) | 7.7 (4) | 1.7 (2) | 8.0 (4) | 11.8 (2) |
Odd ratio (95% CI) | 1.000 | 2.708 (0.651 | 1.000 | 5.087 (0.901 | 7.800 (1.022 |
| 0.156 | 0.051 |
Types of used supplements differed as well by age groups as shown in Table
The major reported reasons for supplement use were to promote muscle gain (47.3%) and to enhance strength (34.4%, Figure
Reasons for supplement use among supplement users (
As shown in Table
Reasons for supplement use by gender and age group (
Reasons for supplement use | Gender | Age group (years) | |||
Men | Woman | 20–30 | 30–40 | 40–50 | |
Disease prevention cluster | |||||
Percentage ( | 7.5 (10) | 69.2 (36) | 17.6 (21) | 22.0 (11) | 82.4 (14) |
Odd ratio (95% CI) | 1.000 | 27.900 (11.655–66.787) | 1.000 | 1.316 (0.581–2.984) | 21.778 (5.742–82.594) |
| <0.001 | <0.001 | |||
Immunity/energy boosting cluster | |||||
Percentage ( | 9.7 (13) | 17.3 (9) | 12.6 (15) | 8.0 (4) | 17.6 (3) |
Odd ratio (95% CI) | 1.000 | 1.948 (0.7778–4.880) | 1.000 | 0.603 (0.190–1.916) | 1.486 (0.382–5.785) |
| 0.149 | 0.516 | |||
Muscle building cluster | |||||
Percentage ( | 85.1 (114) | 40.4 (21) | 81.5 (97) | 62.0 (31) | 41.2 (7) |
Odd ratio (95% CI) | 1.000 | 0.119 (0.057–0.247) | 1.000 | 0.370 (0.177–0.772) | 0.159 (0.054–0.463) |
| <0.001 | <0.001 | |||
Weight/fat loss cluster | |||||
Percentage ( | 50.7 (68) | 23.1 (12) | 42.0 (50) | 52.0 (26) | 23.5 (4) |
Odd ratio (95% CI) | 1.000 | 0.291 (0.141–0.603) | 1.000 | 1.495 (0.770–2.903) | 0.425 (0.131–1.379) |
| 0.001 | 0.115 |
There are no missing data.
CI: confidence interval.
When analyzing the reasons for using nutritional supplements by age group, significant differences were also noted (Table
A big proportion of participants consumed supplements without seeking any professional guidance (Figure
Sources of information among supplement users (
Sources of information regarding nutritional supplements were found to differ among males and females (Table
Source of supplement information by gender and age group (
Source of information | Gender | Age group (years) | |||
Men | Woman | 20–30 | 30–40 | 40–50 | |
Medical/paramedical cluster | |||||
Percentage ( | 42.5 (57) | 88.5 (46) | 46.2 (55) | 66.0 (33) | 88.2 (15) |
Odd ratio (95% CI) | 1.000 | 10.357 (4.139–25.912) | 1.000 | 2.259 (1.136–4.491) | 8.727 (1.911–39.854) |
| <0.001 | 0.001 | |||
Media cluster | |||||
Percantage ( | 55.2 (74) | 21.2 (11) | 50.4 (60) | 38.0 (19) | 35.3 (6) |
Odd ratio (95% CI) | 1.000 | 0.218 (0.013–0.459) | 1.000 | 0.603 (0.307–1.183) | 0.536 (0.186–1.544) |
| <0.001 | 0.223 | |||
Coaches cluster | |||||
Percantage ( | 61.2 (82) | 5.8 (3) | 52.1 (62) | 42.0 (21) | 11.8 (2) |
Odd ratio (95% CI) | 1.000 | 0.039 (0.012–0.131) | 1.000 | 0.666 (0.342–1.297) | 0.123 (0.027–0.560) |
| <0.001 | 0.006 |
There are no missing data.
CI: confidence interval.
When analyzing data according to age group, a trend was also observed (Table
A rate of 87.6% of supplement users reported checking labels on nutritional supplements (data not shown). Amongst those who indicated not reading labels, almost half of them (52.2%) were found to trust enough their trainers.
Our study is the first to illustrate the prevalence use of nutritional supplements among exercisers, not athletes, in gyms in the Middle Eastern region. In the current study, 36.3% of participants reported using nutritional supplements among a representative sample of people exercising at gyms in Beirut city. Such prevalence rate is almost the same as that described in the study of Goston and Correia [
Supplement use patterns were found to differ by gender and total time of exercise. The role of gender as a determinant of supplement use is still not clearly established. In the current study, male exercisers constituted a bigger proportion of supplement users taking into account that more males participated in the study. Similarly, supplement use was reported to be higher among male exercisers [
Similarly to the current study, protein supplements were among the most widely used nutritional ergogenic supplements in other studies, ranging from 28% in Sevilla, Spain [
In the current study, men and younger exercisers focused on supplements generally associated with performance enhancement, body building, and fat reduction including those rich in proteins and amino acids, while women and older exercisers were more concerned with supplements with general health benefits such as those rich in vitamins, minerals, and herbal products. Such pattern has been similarly observed in various studies [
Reasons for selecting nutritional supplements were various, differing as well according to gender and age group. In general, females were more likely to take supplements for health or because of inadequacy in dietary habits, while males reported taking supplements to improve speed, strength, power, and weight/muscle gain [
The increased supplement utilization rates among exercisers could be partially attributed to a positive attitude towards supplements as a part of an appropriate dietary pattern [
This lack of awareness is majorly attributed to the inadequate sources of information of exercisers and athletes regarding nutritional supplements. Nearly 80% of athletes obtain information from “questionable” sources including media, internet, peers, coaches, and trainers [
Media, including books, magazines, television, and internet, was also perceived as a powerful influence on a person’s decision to use nutritional supplements [
Consultation with medical professionals, including physicians and dietitians, is practiced to a lower extent in the sports environment. In the current study, 73.1% of exercisers had never received any guidance from a nutritionist. Similarly, Rocha and Pereira [
Due to the limited knowledge about supplement safety and toxicity, polypharmacy, or the concurrent use of more than one product, is another major issue among athletes and exercisers [
Product labeling was enacted in the United States by the Dietary Supplement Health and Education Act of 1994 in order to protect consumer access to nutritional supplements while providing guidelines for their consumption [
In conclusion, we identify a potential overintake of nutritional supplements among exercisers in the gyms of Beirut city. This pattern reflects a serious public health concern since practiced with minimal professional guidance. As nutritional supplements do not compensate for poor food choices and inadequate dietary habits and as they are not risk-free, it is extremely essential to disseminate accurate and scientifically sound information regarding appropriate use, potential benefits, and possible side effects of these products in the sports environment. Health professionals, including physicians, dietitians, and pharmacists, should combine their expertise with that of coaches and athletic trainers in order to provide more comprehensive nutrition services to exercisers.
The authors have no conflict of interests.
The authors thank the gyms and study participants for their cooperation. They also thank Amanda Yacoub, Darine Shatila, and Lina Akkad who assisted in the collection of data for this study.