How Products Were Selected:
Products tested to represent those popular among readers of ConsumerLab.com and commonly available nationally in the U.S.. ConsumerLab.com purchased products on the open market through retail stores, on-line retailers or direct sales companies. Products were not accepted directly from manufacturers.Testing Methods:
Prebiotic products were tested in one or more independent laboratories for the following:- Total Dietary fiber including percent insoluble and soluble dietary fiber by enzymatic digestion, extraction and filtration followed by gravimetric analysis or high performance liquid chromatography (HPLC) (AOAC 991.43, AOAC 211.25).
- Analyses for lead, arsenic, cadmium and mercury by Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS).
- Disintegration of tablets (excluding chewable, sublingual, and time release formulations) using United States Pharmacopeia (USP) <2040> methodology.
- Disintegration time of enteric coated, time-release, and sustained release tablet, caplet and softgel formulations utilizing USP <2040> methodology for delayed-release (enteric-coated) tablets.
The identities of the products were not disclosed to the laboratories performing the testing.
ConsumerLab.com may modify or use other appropriate test methods if necessary, to test special product formulations.
Passing Score:*
To "Pass", a product had to meet the following requirements:- Total dietary fiber and insoluble fiber, if claimed, must each be within 0.5 grams or 20% of claim, whichever is greater. Soluble dietary fiber, if claimed, must be within 1 gram or 30% of claim, whichever is greater.
- Heavy Metal Contamination: Products tested (designated in the results table) must not exceed the following limits:
Lead:- Products marketed for use by children under 12 years of age may not exceed the State of California's Prop 65 limits for lead in dietary supplements of 0.5 mcg per recommended daily serving with an additional allowance of 0.8 mcg if the product contains more than 1,000 mg/day of calcium.
- Products with a single serving weights of less than 5 grams that are not marketed for use by children under 12 years of age, may not exceed the State of California's Prop 65 limits for lead in dietary supplements of 0.5 mcg per recommended daily serving (above which a warning regarding reproductive harm, birth defects, or cancer risks is required in California) with an additional allowance of 0.4 mcg if containing 250-999 mg/day of any combination of elemental calcium, magnesium and potassium or 0.8 mcg if containing more than 1,000 mg/day of any combination of these minerals. An additional allowance of 0.5 mcg is provided if containing 250-999 mg/day of whole herb (not extract) or 1.0 mcg if containing 1000 mg/day or more of whole herb (not extract). However, total lead allowance must not exceed 2 mcg per daily serving.
- Products with single serving weights of 5 grams or more that are not marketed for children under 12 years of age may not exceed 2.5 mcg per serving nor 4.0 mcg per daily serving.
- Contain less than 10 micrograms of total arsenic per daily serving (based on Canada’s limit per daily serving of a natural health product, and U.S. EPA and state of New Jersey limit in 1 liter of water). Products found to exceed this amount were tested for inorganic arsenic and must not contain more than 2.1 micrograms of inorganic arsenic per daily serving (Canada's additional limit in natural health products).
- If marketed for use by children under 12 years of age, may not exceed 3.0 micrograms of cadmium per recommended daily serving (based on Canada's limit for a child weighing 75lbs). If not marketed for use by children under 12 years of age, may not exceed 4.1 micrograms of cadmium per recommended daily serving (above which California's Prop 65 law requires a "reproductive harm" warning due to developmental toxicity and male reproductive harm.
- May not exceed 2 micrograms of inorganic mercury per daily serving (based on EPA limit for mercury in 1 liter of water).
- If applicable to the product, must meet recommended USP <2040> parameters for disintegration of dietary supplement tablets (excluding chewable, sublingual and time-release products).
- Enteric coated, time-release, and sustained release tablet, caplet and softgel formulations must meet recommended USP <2040> parameters for delayed-release (enteric-coated) tablets by visual inspection.
- Meet FDA labeling requirements.
* Passing scores allow for specific margins of technical error associated with each analysis. ConsumerLab.com reserves the right to disqualify a product at any time from passing its testing if it considers such product to display an unacceptable variation in quality, present a safety risk or to provide misleading or inaccurate information in its labeling.
