Email updates

Keep up to date with the latest news and content from Nutrition Journal and BioMed Central.

Open Access Open Badges Research

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

Gary Gabriels1* and Mike Lambert2

Author Affiliations

1 Department of Medicine, Division of Clinical Pharmacology, Faculty of Health Sciences, Observatory, University of Cape Town, Cape Town 7925, South Africa

2 Department of Human BiologyMedical Research Council/University of Cape Town Research Unit for Exercise Science and Sports Medicine, University of Cape Town, Cape Town, South Africa

For all author emails, please log on.

Nutrition Journal 2013, 12:133  doi:10.1186/1475-2891-12-133

Published: 2 October 2013



The increase in sales of nutritional supplement globally can be attributed, in part, to aggressive marketing by manufacturers, rather than because the nutritional supplements have become more effective. Furthermore, the accuracy of the labelling often goes unchallenged. Therefore, any effects of the supplement, may be due to contaminants or adulterants in these products not reflected on the label.


A self-administered questionnaire was used to determine how consumers of nutritional supplements acquired information to assist their decision-making processes, when purchasing a product. The study was approved by the University of Cape Town, Faculty of Health Sciences Human Research Ethics Committee. The questionnaire consisted of seven, closed and open-ended questions. The participants were asked to respond to the questions according to a defined list of statements. A total of 259 participants completed and returned questionnaires. The data and processing of the returned questionnaires was captured using Windows-based Microsoft® Office Excel 2003 SP 1 (Excel © 1985–2003 Microsoft Corporation). Statistica Version 10 (copyright © Stat Soft, Inc. 1984–2011) was used to calculate the descriptive statistics.


The main finding of the study was that nearly 70% of the respondents who purchased supplements were strongly influenced by container label information that stipulated that the nutritional supplement product is free of banned substances. The second finding was that just over 50% of the respondents attached importance to the quality of the nutritional supplement product information on the container label. The third finding was that about 40% of the respondents were strongly influenced by the ingredients on the labels when they purchased nutritional supplements.


This study, (i) identifies short-comings in current labelling information practices, (ii) provides opportunities to improve label and non-label information and communication, and, (iii) presents the case for quality assurance laboratory “screening testing” of declared and undeclared contaminants and/or adulterants, that could have negative consequences to the consumer.

Nutritional supplements; Information labels; Consumers; Olympics; Paralympics; Physical activity; Laboratory screen testing