As research into the health benefits of food and food components has expanded, food businesses and consumers have developed a greater understanding of the relationship between food and health.
The regulation of health claims for food ensures that claims are based on credible research, which provides consumer confidence in the claims and consumer choice for healthier diets.
In Australia, there are currently two types of health claims. General-level health claims refer to a nutrient or substance in a food and its effect on a health function; for example, “calcium is good for bones and teeth”.
High-level health claims refer to a nutrient or substance in a food and its relationship to a serious disease or to a biomarker of a serious disease. An example is “a diet high in calcium may reduce the risk of osteoporosis in people 65 years and over”.
Recent changes to the Australia New Zealand Foods Standard Code have resulted in a new standard to regulate nutrition content claims and health claims for foods in the advertising of food. While the new standard commenced in January 2013, a three-year transition period will allow concurrent operation of the existing standards.
High-level health claims need to be based on one of the 13 currently pre-approved food-health relationships by Food Standards Australia New Zealand (FSANZ) listed in the standard.
For general-level health claims, the new standard allows two approaches for establishing a food-health relationship. Food businesses may base their claim on one of more than 200 pre-approved food-health relationships in the standard or they may self-substantiate a food-health relationship.
The self-substantiation approach allows a food business to start with an existing systematic review of literature and update it, or to undertake a new systematic review.
What is a systematic review?
A traditional literature review generally collates and describes previous work in a research area of interest (a summary of the literature) without necessarily critically reviewing methodological problems, identifying limitations, adding new knowledge or answering a specific research question.
A systematic review, on the other hand, is an evidence-based literature review focused on a research question that will identify, appraise, select and synthesise all available research evidence relevant to that question.
The evidence-based process consists of a number of steps. First, it involves converting what you need to know into an answerable question (defining the problem). Second, you need to find the best available evidence to answer the question (searching the literature), and third, you must critically appraise the evidence against specific criteria to assess its quality, quantity, consistency, clinical relevance and applicability to the population group of interest (answering the question).
A systematic review is a protocol-driven process with a clearly stated set of objectives and pre-defined eligibility criteria for studies. It involves the assessment individual studies to determine their eligibility against the protocol’s inclusion and exclusion criteria. They then determine the quality, other parameters and the overall levels of evidence of eligible studies.
The systematic review process uses transparent and reproducible methods to enable the ongoing update of completed systematic reviews (if required). Hence, authors of such updates do not need to review information or studies that have been included in a previous systematic review.
For systematic reviews of quantitative evidence, there is an emphasis on minimising experimental and interpretation biases and increasing the reliability of findings. In some cases the results of individual studies can be combined to achieve the required statistical power for meta-analysis to provide an improved estimate of the effects of an intervention. For qualitative evidence the emphasis is on rigour of research design, meaningfulness and appropriateness of the outcomes to a population.
Businesses that would like to make general-level health claims for foods that are not pre-approved by FSANZ will be required to use this systematic review process.
Applying this to food
Requirements for making general level health claims on a food or in an advertisement for a food are set out in Standard 1.2.7 – Nutrition, Health and Related Claims in the Australia New Zealand Food Standards Code.
General-level health claims must go through a substantiation process to establish a relationship between a food, or a property of food and a human health effect. The substantiation process involves evaluating the evidence for a food-health relationship to underpin a general-level health claim.
Evaluation of the evidence gathered through a systematic review process will establish if there is sufficient or insufficient evidence on which to base a food-health relationship.
It is undertaken by a trained reviewer who will select and systematically search relevant scientific and medical databases and other literature sources with a view to locating all studies that meet the eligibility criteria.
External organisations can provide this service. The CSIRO, for instance, has an externally accredited, trained team that undertakes systematic reviews to determine levels of evidence for specific food-health relationships for Australian food and beverage businesses.
CSIRO is an affiliate centre of the Joanna Briggs Institute (JBI), an international collaboration with over 70 centres in 40 countries that promotes and supports evidence-based practices to assist in the improvement of healthcare outcomes globally.
The CSIRO JBI Centre for Food and Health’s expertise in undertaking systematic reviews includes, but is not limited to, explorative scoping and review of areas of interest, design and evaluation of review criteria and process, identification of biases in experimental designs, evaluation of results from human clinical trials and observational studies, validation (including statistical meta-analysis) of experimental results, and synthesis of the evidence to answer the research question.
Where there is insufficient evidence to substantiate a food-health relationship, it may be necessary to validate a food-health relationship via a nutritional or clinical trial.
About the author
Debra Krause is research coordinator for the JBI/CSIRO Evidence-Based Affiliate Centre, with accreditation as a systematic scientific reviewer. She undertakes scientific literature searches and reviews for a range of projects in the food and health sciences area. She has held various food research roles in scientific research organisations for over 30 years. She can be contacted on 03 9731 3280 or at debra.krause@csiro.au.
A step-by-step guide for companies looking to embark on a systematic review:
