Nutritional supplement products: does the label information influence purchasing decisions for the physically active?

The self-administered questionnaire provided the five defined categories, (i) absolutely no influence, (ii) partially no influence, (iii) uncertain, (iv) moderately influenced and (v) strongly influenced that could be selected by participants for the respective container label information. The results are presented for (n = number of respondents), (a) brand name (n = 132), (b) ingredients (n = 129), (c) recommended dosage and directions for use (n = 132), (d) claims (n = 127), (e) disclaimers and warnings (n = 123), (f) quality of product (n = 129), and (g) free of banned substances. (n = 129). Participants could respond to specific labelling information and the extent this influenced their decision making, in the defined categories. The overall results are presented in Figure 2.

The results are presented in the following areas (n = number of respondents), (a) coach, gym and/or fitness trainer, and fellow athletes (n = 67), (b) supplement representatives (n = 63), (c) pharmacist, dietician, nutritionist and doctors (n = 60), (d) print media (n = 67), (e) electronic media (n = 66), and (f) social media and the internet (n = 65). The five categories were scored as previously described, ranging from absolutely no influence to strongly influenced. The pertinent findings of information not on container label that strongly influenced purchase of nutritional supplements based on the percentage number of respondents were; coach, gym and/or fitness trainer, and fellow athletes 24% (n = 16), supplement representatives 2% (n = 1), pharmacist, dietician, nutritionist and doctors 10% (n = 6), print media 12% (n = 8), electronic media 14% (n = 9), and, social media and the internet 9% (n = 6).

The trend based on the study cohort, shows a steady increase in the number of respondents who were not influenced (13%) by the brand name to those who were strongly influenced (36%) by brand name. This finding could be exploited by marketers to encourage consumer brand loyalty.

Seven percent of respondents were not influenced by ingredient content compared to 40% who were strongly influenced by ingredient content. The importance of ingredients in this study is supported by research in publications of Cohen [26] and Lachenmeier [25]. Their research raises concern for the evasive behaviour of some manufacturers, who make it difficult to laboratory detect undeclared ingredients, by incorporating pharmaceutical analogues into their products. That these analogues have never been studied in humans, further adds to the complexity of the situation [26]. Misleading advertising may also cause consequences for the health of the consumers due to chemical risk, if non-approved ingredients are used or contamination occurs [25, 27].

The trend based on the study cohort showed that there was similarity in the number of respondents who were uncertain (25%), moderately (27%), and strongly influenced (21%) with respect to recommended dosage and directions for use. This observation raises concern and shows that the respondents may not necessary have clarity of understanding, of the importance and possible consequence of this type of information, if not applied correctly.

The findings in this study raise concern due to the greater percentage of respondents who were uncertain (30%), if claims information influenced their decision-making. The work of Lachenmeier [25] and Petroczi [14] support the finding of this study, stating that advertisement with claims, typically health or disease claims are misleading or scientifically unproven, despite regulations prohibiting such statements [14, 25]. Further, owing to the market characteristics, enforcement is less straightforward than it is for food or feed, yet the consequences could be more severe as supplements are concentrated [14].

The quality of product trend, showed similarity to that for brand name and ingredients information, indicating an exponential increase in the number of respondents who were not influenced (5%) to those who were strongly influenced (52%). This finding is supported by the work of Cohen [26] that shows an emerging risk to public health, due to the potential overuse of supplements and the paucity of enforcement. Petroczi [14] further reports of supplements that were found to contain more or less than the amount of substance on the label, and for the presence for contamination as a result of poor quality control measures during the product manufacture stage.

The number of respondents who were not influenced (7%) by the supplement being free of banned substances when they were deciding to purchase, was lower than those who were strongly influenced (69%). The importance and assurance of a product being “free of banned substance(s)” by the study cohort studied is encouraging. What is alarming in the context of this finding, is that a recent paper showed that for the consumer to make informed choice there was a need to alert those consuming nutritional supplements of the potential for banned substances being present in products [16, 28]. Of the products labels assessed in that particular study, only 5% had information on, “The presence of banned substances in the supplements”. A supporting paper that assessed the regulations, legislation, and claims associated with nutritional supplements products, concluded that consumer protection provisions should promote greater levels of policy development, regulatory enforcement, and consumer education [6, 15, 29]. Petroczi [14] also reports on the discovery that many supplements contain hazardous substances such as illegal anabolic steroids that have serious known side effects. This is a concern, and points to the importance of having an awareness of the health risk associated with certain hormonal substances and stimulants. This awareness may lead people to opt for “natural” supplements supposedly free of such ingredients [14].

The findings other than the container label information raise awareness of the factors that strongly influences the purchasing of nutritional supplement products. An important finding was that coaches, gym and/or fitness trainers, and fellow athletes (24%), have a greater influence on the choice of nutritional supplement products, than that of a Pharmacist, Dietician, Nutritionist and Doctors (10%). This is contrary to the recommendations of Meltzer [30], which provided a practical guide to the use of nutritional supplements in South Africa, specifically stating that fitness coaches and conditioning staff should not prescribe supplements.

This study showed a steady increase in the number of respondents who were partially not influenced (10%) by a coach, gym, fitness trainer and/or fellow athletes to those who were strongly influenced (24%). This finding is supported by the work of Petroczi [14] that raises public health concerns for supplement consumers who frequently consume beyond the knowledge or remit of clinical practitioners, who act unilaterally or upon the advice of non-experts, such as fellow athletes or coaches. This scenario of poorly informed decision-making, is likely to be more prevalent in the general population where numerous supplements are often taken at levels considerably above the recommended daily allowance [14].

Information provided by supplement representative showed an exponential decrease in the number of respondents who were not influenced (60%) to those who were strongly influenced (2%). This is encouraging as it shows that supplement representatives did not have much influence in the purchase decisions of supplements in the cohort studied.

There was a decreasing trend in the number of respondents who were not influenced (43%) by information provided by Pharmacist, Dietician, Nutritionist and Doctors to those who were strongly influenced (10%). Work by Cohen, which supports this finding, shows that the regulatory environment for supplements is often poorly understood by both consumers and physicians, and also because premarket testing of supplement is not a requirement by most regulators globally [31]. Further, consumers believed that supplements are approved by government agency, and also thought that governments require that labels on supplements include warnings about their potential side effects and dangers. The authors also suggest that medical doctors should maintain a high index of suspicion for using supplements, even when the components on the label are not known to cause the observed effects [26].

There was a steady decrease in the number of respondents who were not influenced (39%) by print media information (e.g. magazines, newspapers) to those who were strongly influenced (12%). This form of information could provide the opportunity for consumer education and awareness that will ensure informed choice, through improved knowledge.

The trend for electronic media was similar to that of print media. There was a steady decrease in the number of respondents who were not influenced (36%) by electronic media information (e.g. television, radio) to those who were strongly influenced (14%). Consumer education and awareness could also be provided via this medium to improve knowledge and so ensure informed choice.

The trend for social media and the internet was similar to the trend for print media and electronic media. There was a steady decrease in the number of respondents who were not influenced (46%) by Social media and the internet information (e.g. website, twitter, Facebook) to those who were strongly influenced (9%).

Internet shops are currently not controlled in depth if at all, with respect to inspections, including sampling and analysis. Yet, large proportion of the supplement market is sold exclusively via this route by companies outside the European Union (EU), and reaches consumers via the postal service. Nutritional supplements also appear to be the most problematic group of products on the internet and hence the importance for professional athletes to be careful, due to contamination or as intentional addition of substances on the World Anti-Doping Agency list [14, 25, 27]. Further, the majority of “sports food” marketed on the web was either found to be ineffective and misleadingly labelled, or if effective, they contained pharmaceutically active substances which are not approved for food use [25]. What these observations imply is that these are potential areas of growth to provide peer-reviewed evidenced-based information.

With hindsight it would have been useful to have included a specific category, “parental influence in purchases”. Furthermore, the findings of this study only relate to the specific groups of moderately physically active and competitive participants between the ages of 19–40 years. It is accepted that younger and older participants, may have responded differently to the questionnaire. There may also have been different influences within the broad professional categories that were used in the questionnaire. Future research in this area should also explore gender or sport-level differences as this could further provide informative insight, on purchasing decision-making.

To enhance the overall quality of supplements there needs to be a concerted effort across sovereign states and continental unions, to align regulatory frameworks and methods of surveillance.

Accredited laboratories with the same status as anti-doping agency laboratories need to be introduced with adequate global standard. In all these cases, a physical sample would be required to judge whether the supplement has complied with the required safety requirements.

Rapid communication system needs to be instituted where contaminated supplements are reported via monitoring and enforcement, within and across sovereign states. The communication respective platforms, should also form the basis for synergy and harmonization, that will contribute to “global” monitoring and enforcement of nutritional supplements. Further, governments should have the responsibility to equip appropriately their law enforcement capabilities, that will alert timeously of “problem products” and with the necessary rigor, have these products recalled.

National Sport and Athlete Coaching forums, Sports confederations and Olympic confederations need to provide knowledge to coaches pertaining to the potential for “supplement doping” to occur. Whilst in the current World anti-doping agency (WADA) regulations, athletes are responsible for what they consume, the consequence for “testing” positive, has negative consequence also for those associated with the “doper”, particular at the high performance level. For the general public, the brief and mandate for Consumer Forums need to be expanded. In the absence of sovereign laws and regulations in the specific area for nutritional supplements, guideline documents, position and policy statements would serve an effective implementation strategy to counter the possibility for “supplement doping”.

In the absence of controlled clinical trials, adverse health effects from dietary/nutritional supplements should be assessed from patients and doctors’ reports, and case studies. Supplements need to be scientifically tested, so that side effects are not inaccurately attributed and diagnosed, and thus leading to incorrect policies and/or warnings.