Basing the criteria for substantiating health claims only on evidence from human intervention studies would not be practical, according to the International Alliance of Dietary/Food Supplement Associations.
Commenting on the latest draft Codex Alimentarius recommendations for the scientific basis of health claims, IADSA said that while the clinical trial model was one source of scientific data, it was not practical when applied to the reduction of risk of disease in persons generally regarded as 'healthy.'
The text is being revised by an electronic working group, of which IADSA is a member. It states that short-term human intervention studies in healthy subjects should be the prime source of evidence in claims substantiation. But it makes no reference to evidence based on traditional knowledge and history of use.
A previous draft of the text was sent back to the drawing board last year in the wake of concerns over the structure of the document and the weight given to the different types of evidence required for scientific substantiation. But the IADSA, which represents 50 trade associations and 20,000 companies, is concerned about the new version.
"It is scientific dogma to state that health claims should be based primarily on well designed human intervention studies," said Professor David Richardson, scientific adviser to the Brussels-based IADSA.
"Much of what is already known about human health cannot be validated using gold standard clinical trials. These studies are, of course, important, but they provide only one source of information.? All sources of scientific data have inherent limitations, hence the need to focus on the totality of the available data and weighing of the evidence."
IADSA said the approach taken in the draft was "medicine-based, aimed at deciding whether a drug can prevent, cure or alleviate a disease or medical condition in the treatment of well-defined groups of people at high risk of disease or already with a disease."
The body argued that nutrition studies in healthy people required a large sample sizes, long-term follow up, high rates of compliance and the taking into account of other lifestyle factors.
Richardson added: "The scientific evidence to support the diet and health relationships for dietary guidelines and health claims for fruits and vegetables, and for whole grain cereals, are based mainly on human observational studies, not clinical interventions."
The text, which will go through an eight-step process to completion, will be presented at the next Codex nutrition committee meeting in November.
Codex, which was established in 1963 jointly by the Food and Agriculture Organisation and the World Health Organisation, is not a regulatory body, so any stand it takes on this issue is not legally binding. However, its views are influential and may be taken into account by governments when drawing up legislation.