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. 2018 Jul;62(14):e1800143.
doi: 10.1002/mnfr.201800143. Epub 2018 Jul 8.

Curcuminoid Content and Safety-Related Markers of Quality of Turmeric Dietary Supplements Sold in an Urban Retail Marketplace in the United States

Meghan B Skiba  1   2 , Paula B Luis  3 , Chelsea Alfafara  1 , Dean Billheimer  2   4 , Claus Schneider  3 , Janet L Funk  1
Affiliations

Curcuminoid Content and Safety-Related Markers of Quality of Turmeric Dietary Supplements Sold in an Urban Retail Marketplace in the United States

Meghan B Skiba et al. Mol Nutr Food Res. 2018 Jul.

Abstract

Scope: Turmeric is a top selling dietary supplement (DS) in the United States with rapidly expanding usage. Therefore, turmeric DS formulations available for sale in an urban US retail marketplace are analyzed, and point of sale information is related to measures of quality relevant to safety.

Methods and results: Eighty-seven unique turmeric DS are identified; a majority (94%) contained turmeric-derived curcuminoid extracts (TD-CE), which are combined with other bioactives in 47% of products, including piperine (24%), an additive that could alter the metabolism of concurrent medications. While curcuminoid content is within 80% of anticipated for a majority of products analyzed (n = 35), curcuminoid composition (% curcumin) did not meet US Pharmacopeia (USP) criteria for TD-CE in 59% and is suggestive of possible unlabeled use of synthetic curcumin in some. Lead content is associated with the inclusion of turmeric root and exceeded USP limits in one product. Residues of toxic class 1 or 2 solvents, which are not needed for TD-CE isolation, are present in 71% of products, although quantified levels were within USP-specified limits.

Conclusion: Assessment of turmeric DS quality at point of sale is difficult for consumers and may best be managed in partnership with knowledgeable healthcare professionals.

Keywords: curcumin; curcuminoids; dietary supplements; lead; solvents; turmeric.

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Conflict of interest statement

CONFLICT OF INTEREST None of the authors have any conflict of interest related to the work reported here.

Figures

Figure 1.
Figure 1.
Unique Turmeric DS Formulations (n= 87). (A) Labeled turmeric-derived content (root, >95% curcuminoid extract, supercritical extract and/or proprietary enhanced bioavailability curcuminoid formulation). (B) Labeled non-turmeric content and/or method of enhancing curcuminoid bioavailability (piperine additive vs. proprietary formulation).
Figure 2.
Figure 2.
Assayed turmeric DS curcuminoid content (n= 35). (A) Total curcuminoid content (g/capsule), as determined by the commercial or academic laboratories, is expressed as a ratio of measured vs. calculated content (based on label information). Scatterplot includes mean ± SD, with dashed lines indicating ratios 20% different than anticipated. Means are not statistically different (p = 0.08). For products with outlying values, sample identification numbers are indicated. (B) Composition of curcuminoids, expressed as % curcumin [CURC], as determined by commercial vs. academic laboratories. Dashed box indicates products with >90% CURC, as assayed by both laboratories. Closed box indicates products meeting USP curcuminoid extract specifications (70–80% CURC), as assayed by both laboratories. Open triangles indicate root-only products, which do not contain curcuminoid extracts.
Figure 3.
Figure 3.
Assayed turmeric DS solvent content (n= 35). (A). The total number of residual class 1,2 or 3 solvents detected per product are indicated. (B) The number of products containing specific class 1,2 or 3 solvent residues are presented.
Figure 4.
Figure 4.
Turmeric DS lead content (n= 35). (A) Lead content, expressed as ppm, is indicated for products, including mean ± SD. For products with outlying values, sample identification numbers are indicated. Dashed line indicates USP specified limit for lead content (1 ppm). (B) Lead content, log transformed to normalize distribution, for products containing root vs no root. Scatter plots indicate individual product and mean (± SD) values. * P < 0.007, root vs no root. Dashed line indicates USP specified limit for lead content.
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