Codex’s stated preference for human intervention trials was an unfair bias that failed to represent all the kinds of evidence available when assessing the veracity of a health claim, said the International Alliance of Dietary/Food Supplement Associations (IADSA).
IADSA will present its views in South Africa next month where the Codex Nutrition Committee is meeting to discuss proposed amendments to a text on the scientific basis of health claims.
Codex Alimentarious is the food guidelines arm of the World Health Organization (WHO) and the Food and Agriculture Organization (FAO).
IADSA said “significant revision” of the current text’s preference for human intervention trials was necessary. It explicitly states short-term human intervention studies in healthy subjects should be the prime source of evidence in claims substantiation.
IADSA says these kinds of trials are important, indeed they could provide the most “persuasive evidence of efficacy in human subjects” but in many cases were not practical. And if they did not exist, a health claim should not necessarily be ruled out.
“Much of what is already known about diet and human health and many existing health claims cannot be validated using gold-standard human intervention studies,” said professor David Richardson, scientific adviser to the UK Council for Responsible Nutrition.
“The clinical trial model is only one source of scientific data and is not practical when applied to the reduction of risk of disease in persons generally regarded as ‘healthy’.”
He suggested evidence should be weighed into four grades, such as ‘convincing, probable, possible and insufficient’. Such as system would “stimulate scientific enterprise and level of investment in research so that scientific knowledge of the relationships between foods and food components and health can advance.”
Professor Richardson pointed out the relationship between a food constituent and health benefits could be tested in many ways.
“The evidence-based approach needs to include the different sources and nature of the evidence, and take into account all relevant studies including human intervention studies, human observational studies, animal studies and in vitro studies as well as other pertinent evidence from consensus reports, evidence-based dietary guidelines and history of use.”
Codex agreed at the end of 2007 that its draft rules on health claims needs further work following concerns over what evidence should be required for scientific substantiation.
IADSA represents about 50 trade associations and 20,000 companies.