IADSA Suggests Framework for Bioactives Recommended Intake

The publication proposes a new framework for recommended intake, enabling the incorporation of aspects of basic, pre-clinical and clinical research – including the Evidence Based Medicine approach of Randomized Controlled Trials.

Nov 2 2011 --- Recommended intake for bioactive food components should be based on the totality of the evidence, the latest scientific publication from the International Alliance of Dietary/Food Supplement Associations (IADSA) has stated.

Titled “Bioactive Food Components: Changing the Scientific Basis for Intake Recommendations”, the publication proposes a new framework for recommended intake, enabling the incorporation of aspects of basic, pre-clinical and clinical research – including the Evidence Based Medicine approach of Randomized Controlled Trials (RCT) – but allowing for decision-making based not primarily on RCT but on the totality of the evidence.

The report, which was released this week and is freely available from the IADSA website, was drafted by Dr David Heber from the Centre for Human Nutrition at the David Geffen School of Medicine, University of California, and Dr Andrew Shao PhD from the IADSA Scientific Group.

It suggests the need for human intervention studies of a smaller scale than those used to evaluate drug efficacy and safety, arguing that RCT used to establish the safety and efficacy of drugs is, alone, not an appropriate method for establishing recommended intakes for nutrients and other bioactive substances.

The report also suggests post-marketing surveillance for potential adverse events.

“Unlike drugs, bioactive substances pose minimal risks when consumed in the nutritional range, and provide evidence for efficacy from a totality of evidence beyond the prospective randomized controlled trials (RCT),” Dr Shao said. “Often they have less marked acute effects which are not apparent or cannot be tested using the RCT. It is not surprising that such an approach often fails to detect any benefit of bioactive substances even when there has been considerable evidence published in the peer-reviewed scientific literature in cell culture, animal models and humans. In fact, it can be argued that this Evidence Based Medicine approach should be reconsidered as a way of evaluating the potential health benefits of bioactive substances.”

Potential elements of the new framework proposed in the report include evidence on the chemical composition; studies showing the biological underpinning of proposed health benefits in appropriate cell culture and animal models; and information on the bioavailability, site of action, absorption and metabolism of the bioactive substance or mixture.

“There is clearly a need to develop a scientific framework to communicate the potential benefits of bioactive substances to the public that establishes reasonable certainty of benefits while also providing assurance of safety,” he continued, “and all scientifically valid evidence of biological effects supporting health benefits based on observations in cell culture, animal models, and in human populations and intervention trials should be considered as a whole in making recommendations for the intake of bioactive substances.”