How Products Were Selected:Products were selected to represent those commonly sold and/or available nationally in the U.S. and Canada. 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, and cadmium by Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) for all products.
- Disintegration of tablets (excluding chewable, sublingual, and time release formulations) using United States Pharmacopeia (USP) <2040> methodology.
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 be "Approved" by Consumerlab.com, a product must meet the following requirements:
- Total dietary fiber, insoluble fiber and soluble fiber found, if claimed, must each be no less than 0.5 gram or 20% of claim (including estimated contributions from isolated or synthetic fiber listed as ingredients but not currently considered Dietary Fiber by the FDA), whichever is greater. (FDA 2021)
- Heavy Metal Contamination: All products must not exceed the following limits:
- Products marketed for use by children 12 years of age or younger may not exceed the State of California's Prop 65 limits for lead in dietary supplements of 0.5 mcg per 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 which are not marketed for use by children 12 years of age or younger, 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 0.4 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 will not exceed 2 mcg.
- Products with single serving weights of 5 grams or more which are not marketed for children 12 years of age or younger may not exceed 2.5 mcg per serving nor 4.0 mcg per daily serving.
- If marketed for use by children, may not exceed 3.0 micrograms of cadmium per recommended daily serving (based on Canada's limit for a child weighing 75 lbs.). If not marketed for use by children, may not exceed 4.1 micrograms of cadmium per recommended daily serving (based on the State of California's Prop 65 limit).
- Contain less than 10 micrograms of total arsenic (EPA limit and state of New Jersey limits - based on 1 liter of water) and no more than 2.1 micrograms of inorganic arsenic per daily serving (Canada's limit in natural health products).
- Meet recommended USP <2040> parameters for disintegration of dietary supplement tablets (excluding chewable, sublingual and time-release products).
- Meet FDA labeling requirements.