Cause-effect relationships in nutritional intervention studies for health claims substantiation: guidance for trial design

Abstract

The growing worldwide interest on functional food research has been accompanied by increasing regulatory guidelines in this area, with the aim of ensuring that any claimed effect in foods, beyond their nutritional role, is based on scientific unequivocal evidence. In order to assess the cause-effect relationship between the regular consumption of a food or a food component and the beneficial outcome for the consumer, an appropriate study design is required. Previous knowledge and research on the specific claimed food or product may be an adequate basis for defining a hypothesis and accurate objectives. Other key factors to take into account are based on the outcomes studied, the length of the trial, sample size and type, as well as the transparency on reporting the results obtained. Based on the Consolidated Standards on Reporting Trials statement (CONSORT), together with the specific guidelines published by the European Food Safety Authority (EFSA) Panel on Dietetic Products, Nutrition and Allergies, the present article aims at summarizing key questions conducting to the most appropriate study design for solid health claim substantiation.

• CONSORT statement
• EFSA
• health claim
• nutritional interventions
• study design

Acknowledgements

The authors gratefully acknowledge CIBERobn (Fisiopatología de la Obesidad y Nutrición, Madrid, Spain) and SEÑ (Spanish Society of Nutrition) for global support concerning the presentations of this guide.

The authors also wish to acknowledge Dr Ana Romo Hualde (Centre for Nutrition Research) for her great support and help all along the development of the project INCOMES (Guide for the Support of Health Claims in foods: Immune and Cognitive functions and Metabolic Syndrome).

Declaration of interest

All authors declare no conflict of interest concerning this supplement.

This work has been supported by the Project INCOMES (Barry Callebaut-La Morella Nuts SA, Biosearch, Biotecnologías Aplicadas SA, Bodega Matarromera SL, Miguel Torres SA, Galletas Gullón SA, Iberfruta SA, Laboratorios Ordesa SL, Newbiotechnic SA and Soria Natural), co-funded by the Spanish Ministerio de Economía y Competitividad (Centro para el Desarrollo Tecnológico Industrial) and FEDER.