Spring 2002 Issue — Foreword

by Professor David Richardson

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The relationship between diet and health is complex and data are often difficult to interpret, especially when the evidence may be derived from a synthesis of clinical, epidemiological, metabolic, animal and in vitro studies.

A new European Union (EU) Concerted Action programme coordinated by the International Life Sciences Institute (ILSI) Europe is aiming to resolve some of the ongoing issues by developing a robust process for the assessment of the scientific support for health claims on foods and food components. This "PASSCLAIM" project is building upon the principles set out in a previous EU Concerted Action on Functional Food Science in Europe (FUFOSE), which was also coordinated by ILSI. This project proposed that "enhanced function" and "disease risk reduction" claims should be based on well-designed studies using appropriately identified, characterised and validated biomarkers. The PASSCLAIM initiative is establishing an evidence-based approach and the objectives are to:

• Produce a generic tool with principles for assessing the scientific support for health-related claims for foods and food components.
• Evaluate critically the existing schemes in the EU Member States and worldwide that assess the scientific substantiation of claims
• Select common criteria for how biomarkers should be identified, validated and used in well-designed studies to explore links between diet and health.

The process for the assessment of health claims that is evolving includes:

The identification of all relevant studies

A health claim must be based on a systematic and objective compilation of all the available scientific evidence. The compilation must be done in a balanced and unbiased way, and individual studies should be evaluated for rigour of design, appropriateness of methods and procedures, reliability of measures of intakes and outcomes, sufficient statistical power etc. The conclusions should illustrate the weight of scientific evidence and the strength and consistency of the evidence will underpin the use of the term "significant, scientific agreement" In other words, the balance of probabilities for the scientific link between a food or food component and a health benefit is justified.

Human studies

In brief, studies on human subjects are accorded greater weight than animal and in vitro (preclinical) studies, and interventional (clinical) studies have greater weight than observational studies. However, the relationship between dietary components and health benefits can be demonstrated by a number of different types of studies and designs, and methodological soundness overrides any hierarchy, given that validity depends not only on the appropriateness of the study type, but also on the quality of its design, execution and analysis. Although well-designed, randomised controlled trials (RCTs) provide the most persuasive evidence of efficacy in human subjects, for many of the firmly accepted precepts of healthy eating, RCT findings are unlikely to be available. In fact, most of the health claims allowed by the USFDA have not had the benefit of RCTs, and cohort (prospective) studies stand out among types of observational epidemiology for their driving role in establishing the links between diet and disease.

Totality of evidence

The determination of the weight of the evidence as a whole requires assessment of the persuasiveness of each relevant study. The overall assessment should be the application of scientific judgement and critical interpretation of the data as a whole. This assessment of the totality of the evidence should be sufficient to permit the conclusion that a change in the dietary intake of the food or food component will result in a health benefit and/or health outcome, including a change in disease endpoint.

Assessment of significant scientific agreement

The use of a health claim should be subjected to rigorous substantiation on a case-by-case basis and depends on the strength and consistency of the body of evidence. The relationship is also not likely to be reversed by new and evolving science, although the exact nature and understanding of the diet/health link will develop and be refined in the normal process of scientific discovery.

This process of substantiation of a health claim will:

1. Benefit consumers by providing information on healthful eating patterns that may help reduce the risk of diseases such as heart disease, some cancers and osteoporosis;
2. Provide consumers and healthcare professionals with a reference point and a measure of confidence that label claims are supported by sound scientific data
3. Provide the claimant with a return on their research investment as well as a measure of insurance when dealing with regulatory agencies
4. Stimulate new research to fill in the knowledge gaps revealed during the course of the scientific reviews.

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