FDA expects a new guidance detailing the boundaries of "competent and reliable scientific information" will enhance consumer confidence in supplement claims.

The guidance was released as part of a broader strategy to fully implement the Dietary Supplement Health & Education Act of 1994. The agency is aiming to increase transparency and initiate more open communication with industry.

"The purpose here it to provide clarity and consistency," Center for Food Safety & Applied Nutrition Deputy Director for Regulatory Affairs Michael Landa said during a Nov. 4 teleconference detailing the enforcement plan.

"We think that if we're clear and transparent in telling people what our expectations are, we'll facilitate compliance, which will have two results: better protection for consumers from products that are unsafe or that make unsubstantiated claims, and...greater public health benefits because of greater degree of confidence that claims are substantiated under an appropriate scientific standard," he said.

The guidance is meant to inform marketers and manufacturers what constitutes "competent and reliable scientific evidence," but does not define a concrete threshold.

"It won't establish a firm benchmark that says if you have this type of claim then you must have one human study and one animal study or two clinical studies," said Robert Moore, team leader for compliance & enforcement in CFSAN's Division of Dietary Supplement Programs, Office of Nutritional Products, Labeling & Dietary Supplements.

"The draft is flexible because of the fact that different types of evidence will be sufficient to substantiate different types of claims," Landa added.

The guidance is part of an effort to eliminate unsubstantiated claims; in October, the agency sent eight warning letters to marketers of weight-loss supplements citing a lack of "competent and reliable scientific evidence".

To ascertain whether the standard has been met, firms should determine: all possible interpretations of the claim; the relationship between the claim and the supporting evidence; and the quality and totality of the evidence.

The agency recommends studies submitted as support "identify a specific dietary supplement or ingredient and serving size and that all conditions of use in the studies be similar to the labeling conditions" detailed on product packaging.

The guidance specifically reminds manufacturers that "other substances involved in the study or included in the dietary supplement itself might also affect the dietary supplement's performance or the study results." In other words, results should be carefully evaluated to be sure the impact is related to a particular ingredient.

In order for a study to be considered adequate, study cohorts should mirror the intended population, FDA notes. For instance, results from a study involving young adults cannot be extrapolated to make a claim regarding the product's effect on the elderly, the guidance states.

In this vein, foreign data should be carefully scrutinized. "Differences in diets, general health or patterns of use could confound the results," the agency warns.

For example, FDA notes that data from a well-designed, randomized, placebo-controlled study conducted overseas cannot always be extrapolated to the U.S. since the study population may have had a particular mineral deficiency that elicited the outcome, and the local U.S. population may not experience the same result.

Intervention trials are among the most appropriate studies to be used as substantiation because they "evaluate the product's direct effect in the human body," according to the guidance. However, "generalizing from such evidence on selected populations is cautioned," FDA says.

Observational studies may produce more limited data and result in measurement errors, but are advantageous because they cost less and require a smaller study population. Case reports, case-series studies, cohort studies and epidemiological studies are among observational trials that may yield adequate data.

The agency categories in vitro and animal studies, testimonials and meta-analyses as information that "may not be adequate to substantiate a claim."

Supplement Substantiation Claims Guidance Aims For Clarity

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