EFSA update: Fully defining microbiota cause-and-effect

Microbiota changes should be linked to physiological or clinical outcomes of which a direct effect on human health can be attributed to a specific mechanism of action.

That was the opinion of Dr Yolanda Sanz, member of the Dietetic Products, Nutrition and Allergies (NDA) Panel at EFSA, who was speaking at Probiota in Amsterdam last week.

Sanz believed that hard health endpoints, not just changes to the microbiota, were needed to secure EU prebiotic health claims. Submitted studies to EFSA showed food constituents increased gastro-intestinal microbiota but were unable to show such a change would result in a beneficial physiological effect.

Other studies designed to show a reduction of disease incidence also failed to identify risk factors.

“This is a requirement and restriction, imposed in a regulatory context, because we cannot state on labels that the foodstuff can treat or prevent a disease,” said Sanz.

“It is new regulatory framework that we will have to learn to live with and adapt to,” she added.

Sanz claimed that in the context of disease risk reduction, EFSA had only received claims that reduced the risk of infection. Claims needed to show the risk factor contributed to the disease by establishing the independent association between the risk factor and an increased risk of infection.                                                                                                                                                                                                    

In addition, there needed to be clear evidence of a biological basis through which the risk factor contributed to the infection. Submitted evidence would only need to show modification of this risk factor. She cited the example of Clostridium difficile’s toxigenic action on the host.

“If you are making a claim for less-well established risk factors, for example the link between a decrease in immunoglobulin A production and higher a risk of developing a respiratory tract infection, then you would need to provide evidence of the clinical outcome leading to the reduction of the disease incidence and reduction of this risk factor,” she added.

EFSA update: What’s New?

Sanz pointed towards recent efforts made by EFSA to improve the dialogue between the different stakeholders and guidance on gut immune pathogen claims. As well as its discussion paper on the content (June-September 2014), a guidance draft (February-March 2015) was produced to take into account scientific advances and comments gathered during consultation with experts and stakeholders. Further advice (1,2) for applicants seeking approval of claims was also recently published.

Updates to EFSA’s claims guidance included moving the characterisation section from the gut-immune advice to the general guidance on claims. Sanz added that the identification of the bacterial species and strain was the responsibility of the applicant since effects were strain specific, unless the opposite could be demonstrated.   

New molecular tools have been added according to methods that have become popular in this field. This includes multi-locus sequence typing, optical mapping, and whole-genome sequencing. The list has been left open in anticipation of newer, more powerful technology in future.

Sanz acknowledged that several study methods often needed to be used in combination, citing the use of a target population versus a study population. 

Whether the target population can be subjects under medication to reduce side effects of the medication (antibiotic-associated diarrhoea) depended on acceptability by risk managers. Sanz recommended consulting admissibility guidelines if this approach was taken.

The study population can be appropriate for substantiating a claim for general population was the scientific judgement of the EFSA panel. Sanz cited a recent study that EFSA had accepted the use of IBS patients as the study population to address a claim for gastro-intestinal discomfort.