Quality of systematic reviews of the Foods with Function Claims registered at the Consumer Affairs Agency Web site in Japan: a prospective systematic review

The objective of this review was to assess the quality of systematic reviews (SRs) based on the Foods with Function Claims (FFC) registered at the Consumer Affairs Agency (CAA) Web site in Japan by AMSTAR checklist. Study design was a prospective SR of SRs based on the FFC registered at the CAA Web site in Japan. We searched the database from 1 April 2015 (starting date) through 27 October 2015 on the CAA Web site. A full quality appraisal of identified articles was made using the combined tool based on the AMSTAR checklist developed to assess the methodological quality of SRs. Each item was scored as “present” (yes), “absent” (no), “unclear or inadequately described” (cannot answer), or “not applicable” (N/A). Forty-nine SRs met inclusion criteria. The quality of the articles was in the poor description category (mean ± SD; 6.2 ± 1.8 points, range; 2-11 points). Especially, there were very poor descriptions and/or implementations regarding the registration (2%), evaluation of publication bias (12%), and appropriate conclusions based on scientific quality of the included studies (27%). As a whole, the quality of SRs based on the FFC was poor in methodology and reporting. To develop SRs of the FFC and healthy foods, it will be important for future research to introduce and use (1) the AMSTAR checklist (ie, a tool to assess the methodological quality of SRs), (2) the PRISMA (ie, a checklist in the general description of SRs) and PRISMA-NMA checklists (ie, a checklist in the specific description of SRs with meta-analysis), (3) many English databases, (4) development of the original checklist for the FFC and healthy foods, and (5) notification documents (including SR) of the FFC in English.