Assessment of health claims, content, and safety of herbal supplements containing Ginkgo biloba

BACKGROUND: European Regulation 1924/2006 states that all health claims made on foods need to be substantiated scientifically. OBJECTIVE: To apply the PASSCLAIM criteria for the scientific substantiation of health claims on foods to herbal supplements containing Ginkgo biloba. Evaluation of three selected claimed health effects for G. biloba (improvement of blood circulation, improvement of symptoms of old age, and improvement of memory) was achieved through review of publicly available scientific data. A total of 35 human intervention studies were evaluated. Commercially available products claimed to contain mainly G. biloba (N=29) were randomly sampled in the Netherlands and analyzed for their content on ginkgo extract. Also, a toxicological risk assessment was performed. RESULTS: The three selected health claims investigated could not be substantiated. This was mainly because of a lack of data from studies in healthy volunteers. In most studies results performed with a 24% standardized G. biloba extract were described. However, our chemical analysis showed that 25 of the 29 sampled products did not contain the required minimum 24% standardized extract. Moreover, in most preparations the content of substances typical for G. biloba did not conform to what was declared on the label. Since toxicity data for G. biloba are very limited, a safety limit could not be established. CONCLUSIONS: Evidence is lacking for three health claims of herbal products with G. biloba. Neither safety nor efficacy can be guaranteed at the recommended daily dose. The multidisciplinary approach described in this paper provides good insight into issues that are relevant for the evaluation of health claims for herbal food supplements.