FDA warns consumers about weight loss products & issues claim substantiation guidance.

In late December, FDA alerted consumers nationwide not to purchase or consume 69 different products marketed for weight loss because they contain undeclared, active pharmaceutical ingredients that may put consumers' health at risk. An FDA analysis found that the undeclared active pharmaceutical ingredients in some of these products include sibutramine (a controlled substance), rimonabant (a drug not approved for marketing in the U.S.), phenytoin (an anti-seizure medication), phenolphthalein (a solution used in chemical experiments and a suspected cancer causing agent) and bumetanide (a diuretic).

The amount of some active pharmaceutical ingredients far exceeded the FDA-recommended levels, putting consumers' health at risk. These weight loss products, some of which are marketed as "dietary supplements," are promoted and sold on various websites and in some retail stores. Some of the products claim to be "natural" or to contain only "herbal" ingredients. These products have not been approved by FDA, are illegal and may be potentially harmful to unsuspecting consumers, the agency said. The health risks posed by these products can be serious; for example, sibutramine can cause high blood pressure, seizures, tachycardia, palpitations, heart attack or stroke. This drug can also interact with other medications that patients may be taking and increase their risk of adverse drug events.

FDA/Center for Food Safety and Applied Nutrition (CFSAN) has also issued a guidance document for the dietary supplement industry regarding claim substantiation required by Section 403(r) (6) of the Federal Food, Drug and Cosmetic Act. In determining whether the substantiation standard has been met with competent and reliable scientific evidence, FDA recommends that firms consider four issues in their assessment: the meaning of the claim (s) being made; the relationship of the evidence to the claim; the quality of the evidence; and the totality of the evidence. When a claim may have more than one reasonable interpretation, FDA recommends that a firm have substantiation for each interpretation. It recommends that firms not only focus on individual statements or phrases, but also on what expected effect or benefit is being promoted when all of the statements being made for the product are considered together. Studies used to substantiate dietary supplement claims should identify a specific supplement or ingredient and serving size, and the conditions of use in the studies should be similar to the labeling conditions of the product.

Scientific quality of studies is also an important consideration and should be based on several criteria, including study population, study design and conduct, data collection, statistical analysis and outcome measures. In determining whether there is adequate evidence to substantiate a claim, one should consider the strength of the entire body of evidence, including criteria such as quality, quantity, relevance of exposure and consistency and replication of the findings.