Adolescent athletes have better general than sports nutrition knowledge and lack awareness of supplement recommendations: a systematic literature review

Nutrition knowledge (NK) impacts food choices and may be improved through educational programmes. Identifying knowledge gaps related to NK among adolescent athletes may guide future nutrition education programmes. This review aimed to systematically review the level of NK in adolescent athletes based on the currently available published literature. The protocol for this review was registered with PROSPERO (CRD42022321765). A literature search was conducted in April 2022 using MEDLINE, CINAHL, SPORTDiscus, Web of Science and SCOPUS databases. The study design was not restricted, provided that a quantitative NK score was reported for adolescent athletes. Studies were limited to the English language and published between 2010 and April 2022. Studies were assessed for quality and risk of bias using the Academy of Nutrition and Dietetics Quality Appraisal Checklist. Data extracted included demographics, questionnaire name, number of items, validation status and mean total and subsection NK scores. Meta-analyses were inappropriate due to the heterogeneity of NK assessment tools; therefore, results were presented narratively. Thirty-two studies that assessed NK of 4553 adolescent athletes and 574 comparison participants were included. Critical appraisal of studies resulted in neutral rating 'moderate quality' for most (n 30) studies. Studies lacked justification for sample size and often used inadequately validated questionnaires. NK scores ranged from poor (33·3 %) to excellent (90·6 %). The level of NK across studies is difficult to determine due to heterogenous questionnaires often lacking appropriate validation. NK should be assessed using tools validated in the relevant population or revalidated tools previously used for other populations.

Appearance and performance factors associated with muscle building supplement use and favourable attitudes towards anabolic steroids in adolescent boys

Introduction

The demand for appearance and performance enhancing substances, including muscle building supplements and anabolic androgenic steroids, is increasing in Australia. However, little is known about the associations between appearance and performance-based factors and appearance and performance enhancing substances (APES), particularly among adolescent boys. This study sought to examine (a) the prevalence of muscle building supplement use in a sample of adolescent boys and (b) how both performance and appearance factors relate to muscle building supplement use and favourable attitudes towards anabolic androgenic steroids in this sample.

Method

N = 488 adolescent boys aged 13-16 (Mage = 14.59) from nine Australian schools completed measures of supplement use, favourable attitudes towards using steroids, muscle dissatisfaction, body fat dissatisfaction, mesomorphic ideal internalisation, weight training, and sports participation. Hierarchical logistic regressions were used to examine cross-sectional correlates of muscle building supplement use and favourable attitudes towards using anabolic androgenic steroids.

Results

In the past three months, 12.7% of the sample had used muscle building supplements. Both appearance and performance-related factors - mesomorphic ideal internalisation and weight training - were related to muscle building supplement use. Only one appearance-related factor - body dissatisfaction - was related to favourable attitudes towards anabolic androgenic steroids.

Discussion

The findings from this study are important as they may help to guide intervention strategies regarding appearance and performance enhancing substance use by Australian adolescent boys, with the ultimate goal of ensuring this population's safety.

Whey Protein Dietary Supplements: Metal Exposure Assessment and Risk Characterization

Protein supplements (PS) are trendy foods, especially those made from whey. In addition to providing protein, these products are a source of metals, providing essential elements (Na, K, Mg, Ca, Mo, Mn, Fe, Co, Cu, and Zn) and other potentially toxic elements (Al, B, Sr, V Ba, and Ni). In this study, 47 whey PS samples were analyzed for mineral elements by ICP-OES, and their dietary exposures were assessed for three consumption scenarios. Elements found in higher concentrations were K (4689.10 mg/kg) and Ca (3811.27 mg/kg). The intake of 30 g PS (average recommended amount/day) provides about 20% of the established reference value (NRI) for Cr (18.30% for men and 25.63% for women) and Mo (26.99%). In a high daily consumption scenario (100 g PS/day) and when the maximum concentrations are considered, Cr, Zn, Fe, Mo, and Mg dietary intakes of these metals exceed the daily recommended intakes and could pose a risk. The daily intake of 30, 60, and 100 g of whey PS for 25 years does not pose a health risk since the hazard index (HI) is less than one in these consumption scenarios, and the essential elements contributing most to HI are Co, followed by Mo and Cr. It is recommended to improve the information to the consumers of these new products. Furthermore, to help in the management and prevention of these potential health risks, it would be advisable to improve the regulation of these dietary supplements and their labeling.

Measured versus label declared macronutrient and calorie content in Colombian commercially available whey proteins

Whey protein (WP) supplements have grown in popularity for exercising populations to enhance muscle protein synthesis and promote recovery. The purpose of this investigation was to examine the macronutrient profile, especially protein, of commonly sold protein powder brands in the Colombian (South America) sports supplement market. Eleven popular whey proteins supplements made and sold on the Colombian market were sampled and determined the humidity, ash, total carbohydrates, fat, proteins, and calories (kcal). The mean calorie content declared by product labeling was significantly lower (p < 0.05) than measured (labeled 349.8 ± 20.3 kcal; analyzed 368.2 ± 14.9 kcal). Carbohydrate content was higher than labeled on average (labeled 3.5 ± 6 g/100 g; analyzed 21.9 ± 12.5 g/100 g) (p < 0.05). The protein content on the labels showed a significantly higher content, on average, than analyzed in all samples (labeled 81.4 ± 7.4; analyzed 65.7 ± 14.1) (p < 0.05). These data suggest, that for brands analyzed in this research, nutrient labels may be misleading, especially regarding protein, carbohydrate, and total calorie content. Consumers should diligently read, but also learn the different product labeling; however, brands should emphasize on testing their products and add amino acid profiles to guarantee quality of their products.

Influence of 5-Week Snack Supplementation with the Addition of Gelatin Hydrolysates from Carp Skins on Pro-Oxidative and Antioxidant Balance Disturbances (TOS, TAS) in a Group of Athletes

The research objective was to assess the effects of 5-week snack supplementation with added enzymatic hydrolysates from carp skins on shifts in pro-oxidative and antioxidant balance among athletes. The study comprised 49 adults (experimental group (E)—17, placebo (P)—16, control (C)—16) practicing endurance disciplines. Selected somatic indices and maximal oxygen uptake/m (VO2max) were measured. Based on VO2max, an individual exercise intensity was selected with predominating eccentric contractions (60% VO2max). The conducted tests consisted of 2 series (1st—graded and eccentric, 2nd—eccentric). The experimental group consumed a snack with added gelatin hydrolysates from carp skins for 5 weeks in between the series, the placebo—a snack without added hydrolysates, and in the control—no supplementation was implemented. Blood samples were taken before, and 1, 24 and 48 h after completion of the eccentric test. TAS and TOC concentrations in the blood plasma were assessed. No significant changes in TOS/TOC and TAS/TAC concentrations were noted between the 1st and the 2nd test series, before or following the eccentric test in the control and placebo groups. In the measurements performed 1, 24 and 48 h after completion, the observed differences were highly significant (p < 0.001). After 5 weeks of snack consumption, an increase from medium to high antioxidant potential was observed for E. Differences between the 1st and the 2nd test series were of high statistical significance (p < 0.001). The demonstrated differences in pro-oxidative-antioxidant balance indices between successive series allow to confirm antioxidant effects and indicate possibilities for its implementation, not only in sports.

Dietary Supplements Use among Athletes in Lebanon: Knowledge, Attitudes, Practices, and Correlates

Athletes are under the utmost pressure to reach excellence in their performance and achieve the desired outcomes in competitions, prompting them to use dietary supplements. Given the threats to both health and eligibility, it is crucial to observe the prevalence, sources of information, knowledge, attitudes, and practices (KAPs) among Lebanese athletes practicing their sports for at least two years. In the present paper, a cross-sectional study is performed using the snowball sampling method, in which a self-administered KAP questionnaire is used to collect data from 455 athletes (mean age: 27.4 ± 7.9 years; men: 73.1%) participating in four sports categories (ball games, combat sports, endurance sports, and weightlifting). Among the Lebanese athletes, the prevalence of dietary supplement (DS) use was 74%, where half of them had predominately used sports supplements. Athletes in Lebanon heavily rely on coaches (74%) and online sources, including webpages and social media (64%), as key information sources for DSs. The findings suggest that significant proportions of athletes show knowledge deficits and unsatisfactory attitudes towards multiple aspects related to supplementation. Moreover, education and sports type modulate the use of DSs among athletes. Furthermore, 34% reported using supplements without a recommendation from specialists, and 69% admitted to not reading the supplement's nutrition facts. This study urges the need for the regulation of concerned authorities and education programs to help overcome the existing challenges.

Prevalence and Attitudes Towards Using Protein Supplements Among Female Gym Users: An Online Survey

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.

Protein, Creatine, and Dieting Supplements Among Adolescents: Use and Associations With Eating Disorder Risk Factors, Exercise-, and Sports Participation, and Immigrant Status

Objective: This study aimed to estimate the number of weekly users of protein, creatine, and dieting supplements and to explore whether weekly use was related to eating disorder (ED) risk factors, exercise, sports participation, and immigrant status.

Methods: In total, 629 and 1,060 high school boys and girls, respectively, self-reported weekly frequency of protein, creatine, and dieting supplement use, and weight and shape concerns, appearance internalization and pressure, self-esteem, mental distress, physical activity level, exercise context, and the type and weekly frequency of sport played. Multiple hierarchical regression analyses were performed to investigate explanatory factors for supplement use.

Results: More boys than girls used protein and creatine supplements. Immigrant boys had more frequent use of all supplements than non-immigrant boys, and immigrant girls used creatine supplements more frequently than non-immigrant girls. In total, 23–40 and 5–6% of the variation in the weekly frequency of supplement use in boys and girls, respectively, was explained by immigrant status, ED risk factors, and exercise and sports participation. More frequent use of protein, creatine and dieting supplements in boys was significantly explained by more weight and shape concerns, fitness center exercise, and weight-sensitive sports participation. Depending on the type of supplement, more frequent use of supplements in girls was significantly explained by lower self-esteem, more engagement in weight-sensitive sports, and less engagement in general sport and exercise activities.

Conclusion: Weekly supplement use was common and more frequent among boys than girls. The weekly use of protein, creatine, and dieting supplements was related to ED risk factors, exercise and sports participation, and immigrant status in boys but not in girls.

Anabolic-androgenic steroids and dietary supplements among resistance trained individuals in western cities of Saudi Arabia

Background

Anabolic–androgenic steroids (AAS) contain testosterone-like androgens and are used as supplements to improve performance, therapeutic measures, appearance, and muscular development.

Purpose

This study aimed to estimate using anabolic–androgenic steroids (AAS) and good and bad practices about dietary supplements among resistance-trained individuals. It further seeked to determine the use of common drugs and supplements containing anabolic steroids among resistance-trained individuals (who work out at the sports centre) and assess users' knowledge about its side effects.

Methods

A cross-sectional survey was conducted at the sports centres of the western cities of Saudi Arabia. A self-administered questionnaire was used to collect data from 120 male resistance-trained individuals.

Results

The majority of the participants (80%) reported that they had not used any hormonal bodybuilding supplement last year, while 20% said they had used such hormonal supplements. Approximately half (52.5%) of participants reported that they always used dietary supplements. A total of 44.2% of participants possessed inadequate knowledge of these products. The main reason behind the use of hormones and supplements was to increase muscle mass.

Conclusions

A minority of resistance-trained individuals in the studied population frequently misused AAS. However, the results cannot be generalised to the whole of Saudi Arabia. AAS consumption can be reduced by enhancing the level of awareness and knowledge of potential adverse health outcomes.

Prevalence of Protein and Pre-Workout Supplement Use among High School Football Players and Potential Product Contamination

The purpose was to determine the prevalence of protein and pre-workout supplement usage in high school football players and how many products contained banned substances or dangerous ingredients. A national sample of 102 high school football players was recruited via Qualtrics Research Panels to complete a cross-sectional online questionnaire. Data were summarized as means with standard deviations (SDs) and frequencies with proportions (%). A majority (59.8%) of high school football players reported currently using a protein supplement. Just under one-third (29.4%) reported currently using pre-workout supplements. Five participants reported using a pre-workout product that contained a known NCAA banned substance. Many of the products used contain banned, regulated elsewhere, or unknown substances. Secondary school ATs must educate athletes regarding the use of nutritional supplements and the potential dangers of ingesting banned or unknown substances.

Quality Control of Protein Supplements: A Review

The growing consumer awareness regarding health and fitness has been leading to a huge rise in the consumption of nutritional supplements and, consequently, to an increase in concerns about their quality. In this sense, one of the most consumed products is protein supplements and, despite being safer than other types of supplements, there are several studies showing incompatibilities between what is present on the labels and their actual content. Therefore, this review is focused on gathering information about the problems arising from poor manufacturing practices and inadequate quality control of sport protein supplements. These issues are mainly related to three aspects: reduction of the supplements’ nutritional value, the presence of pharmacological substances, and contamination with microorganisms or toxic metals. Regarding the first aspect, reports about the “classic” addition of nitrogen-rich compounds to mask the protein content measured by the Kjeldahl method were discussed, as well as recent topics such as the addition of cheaper proteins to produce an “undetectable” adulteration in whey protein supplements. With respect to the presence of pharmacological compounds, it is a finding that is not very common in protein supplements; however, even trace amounts of foreign substances in this type of product may cause adverse effects to consumers, and, in the case of an elite athlete, may result in doping. Finally, we discuss about the contamination with microorganisms and toxic metals, this latter being a subject that should be further explored due to few studies in the literature.

Age group determines the acceptability of protein derived off-flavour

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Heat-treatment of protein ingredients can impart sulfurous flavours into beverages.

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Sulfurous flavours negatively impacted consumer acceptance of a dairy beverage.

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Older adults had greater acceptance of sulfurous flavours compared to younger adults.

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Diacetyl reduced the negative impact of these compounds for both age groups.

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Best estimate thresholds give a conservative estimate of off-flavour acceptability.

Many older adults fail to meet their daily protein requirements, potentially due to social, physical and medical factors, including sensory and appetite changes. Additionally, our previous research has identified potential sulfurous off-flavours, originating from heat-treatment of protein ingredients, which could play a role in consumer acceptance. This study aims to determine the hedonic impact of these potential off-flavours when added to a dairy beverage, identify the specific off-flavour concentrations which cause rejection by consumers, and lastly investigate difference in acceptance between older and younger consumers. A rejection threshold (RjT) protocol was used, in combination with Best Estimate Thresholds (BET), whereby sulfurous flavours (dimethyl sulfide, dimethyl disulfide and dimethyl trisulfide), and diacetyl were added to create a range of concentrations. 95 participants (younger n = 49, 18–38 years; older n = 46, 60–79 years) tasted 7 pairs of samples (one blank and one with ascending off-flavour concentration) and selected their preferred samples. Sulfurous flavours negatively impacted consumer acceptance, however, the extent to which they impart a negative effect differs between age groups. Younger adults rejected samples containing low concentrations of sulfurous off-flavours (1.55 ppb), however, older adults rejected samples with concentrations over 3 times higher (5.08 ppb). When combined with sulfurous flavours, diacetyl increased the rejection threshold for both groups. In conclusion, these observations imply that a greater quantity of off-flavour may be present before acceptance is reduced in the older consumer group. Moreover, diacetyl demonstrates partial masking abilities of sulfurous off-flavours, and BET gave a more conservative estimate of acceptability. This knowledge will help guide sensory innovation of high-protein beverages for older consumers to support product acceptance and optimal intake.

Muscle building supplement use in Australian adolescent boys: relationships with body image, weight lifting, and sports engagement

Background

The extent and implications of muscle building protein supplement use among adolescents is relatively unknown. This study aimed to describe the prevalence of protein powder, creatine, and anabolic steroid use in a sample of 14–16 year-old boys in Australia, and the predictors of actual use, and intentions to use protein powder.

Methods

Data were obtained from questionnaires with Australian adolescent boys aged 14–16 years from one independent boy’s school in Melbourne (N = 237). Hierarchical linear and logistic regressions were used to determine the predictors of intentions, and actual use of protein powder.

Results

49.8% of boys reported current use of, and 62% intended to use protein powder; 8.4% used creatine, and 4.2% used anabolic steroids. Higher levels of drive for muscularity, participation in weight training, and playing a greater number of sports were significant predictors of higher current use and intentions to use protein powder, but age, BMI, body esteem, and ethnicity were not.

Conclusions

Prevalence of muscle building supplement use was relatively high among this adolescent population. This research has implications for intervention and prevention programs to educate young boys about muscle building supplements to reduce negative physical and psychological health effects of their use.

Validation of the Athlete's Plate Nutrition Educational Tool: Phase I

Nutrition education visual tools are designed to help the general population translate science into practice. The purpose of this study was to validate the Athlete's Plate (AP) to ensure that it meets the current sport nutrition recommendations for athletes. Twelve registered dietitians (RDs; 10 female and 2 male) volunteered for the study. Each registered dietitian was asked to create three real and virtual plates at three different times corresponding to breakfast, lunch, and dinner, and the three different AP training loads, easy (E), moderate (M), and hard (H), divided into two weight categories (male 75 kg and female 60 kg). Data of the real and virtual plates were evaluated using Computrition software (v. 18.1; Computrition, Chatsworth, CA). Statistical analyses were conducted by SPSS (version 23.0; IBM, Armonk, NY) to compare the difference between each training load category (E, M, and H) and the recommendations. No statistically significant differences were found among the created plates and the recommendations for energy, carbohydrates, fat, and fiber for E, M, and H. Protein relative to body mass (BM) was higher than recommended for E (1.9 ± 0.3 g·kg-1 BM·day-1, p = .003), M (2.3 ± 0.3 g·kg-1 BM·day-1, p < .001), and H (2.9+0.5 g·kg-1 BM·day-1, p < .001). No differences were found for the macronutrient distribution by gender when correcting for kilograms of body mass. The authors conclude that the AP meets the nutrition recommendations for athletes at different training intensities for energy, carbohydrates, fat, and fiber, but exceeds the recommendations for protein. Further research should consider this protein discrepancy and develop an AP model that meets, besides health and performance goals, contemporary guidelines for sustainability.

Protein supplement consumption is linked to time spent exercising and high-protein content foods: A multicentric observational study

The main aim of this study is to analyze if protein supplement consumption and food patterns vary across three geographical regions and secondly to identify possible factors that increase the likelihood of ingesting protein supplements. A total of 916 responses from gym users of 3 countries (Italy, Turkey and UK) were entered for analysis. Questions were related to supplement consumption (protein and other supplements), food intake and training habits. A descriptive analysis, analysis of variance (ANOVA), and logistic regression were performed. No differences were found across groups regarding: prevalence of protein supplement consumption, typology of other ingested supplement and food intake. No relation was found between level of education (r = .12) or geographical region (r = .16) and protein consumption. The analysis showed that the coach is the main source of suggestion for the intake of protein supplements (52.3%). The logistic regression model highlighted that gym users who exercised more (OR 1.51, p < 0.001) and consumed higher quantities of chicken (OR 1.39, p < 0.001) eggs (OR 1.18, p < 0.001) and canned tuna (OR 1.15, p < 0.05) were more likely to use protein supplements. Geographical area does not seem to influence the supplementation pattern. Time spent exercising and high protein foods are factors associated with protein supplement consumption.

Use of nutritional supplements contaminated with banned doping substances by recreational adolescent athletes in Athens, Greece

Although the use of nutritional supplements by adult athletes has been extensively studied, information on supplements consumption by adolescent athletes is still limited. The present study reports on the use of nutritional supplements contaminated with banned doping substances among 170 recreational adolescent athletes from eleven, randomly selected, gym centres, in Athens, Greece. Nutritional supplements consumption was reported by almost 60% of the study population, with proteins/amino acids and vitamins being the most popular. Nine per cent of the users were found to consume nutritional supplements contaminated with anabolic steroids, prohormones, selective androgen receptor modulators (SARMs) and aromatase inhibitors, all pharmacological substances with endocrine modulating properties not stated on the label. None of these individuals had previously consulted a physician or a nutritionist. A representative sample (ca 15%) of the protein/aminoacids and creatine preparations used by the study population were also tested and found free from doping substances. The majority (63%) of adolescents purchased products from the internet. In conclusion, exercising adolescents can have easy access to contaminated nutritional supplements and "black market" products, which could constitute a risk for public health. Low level of awareness and low involvement of medical care professionals among recreational adolescent athletes is also observed.