Abstract
PURPOSE
The World Wide Web has become a significant source of health information for the public, but there is concern that much of the information is inaccurate, misleading, and unsupported by scientific evidence. To explore this issue, the validity of health claims for the herb Opuntia on the World Wide Web was analyzed.
DATA SOURCES
From December 1998 to May 1999, health claims were identified from Web sites utilizing nine search engines. A corresponding search was conducted of the scientific literature. Search terms included common and botanical names for Opuntia.
INCLUSION AND EXCLUSION CRITERIA
Nutritional support guidelines for herbs were used to identify claims from relevant sites. Scientific studies included established methodological designs with no restrictions on source, language, type of subjects, or dosage forms for Opuntia.
DATA EXTRACTION METHODS
A checklist of significant information was prepared for Web sites and scientific studies. The quality of scientific studies was assessed with two instruments, the Jadad and the Journal of the American Medical Association (JAMA) scales.
DATA SYNTHESIS
Validity of health claims on Web sites was compared with scientific reports. Searches retrieved 184 Web sites, 98 with health claims and 51 with research studies. Only 34% of the claims were addressed in the scientific literature, and evidence was conflicting or contradictory. For human studies, none met the criteria for high quality as determined by the Jadad and JAMA scales.
MAJOR CONCLUSIONS
The majority of health claims were based on folklore or indirect scientific evidence and could not be validated by scientific research. This suggests a need to check the validity of herbal information on the World Wide Web.
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