Vitamin D Testing & 3rd Party Certification
A letter in a recent medical journal stated that in a recent study the only vitamin D supplement to pass the authors’ potency testing was a USP-verified product. The authors explicitly endorsed the USP certification program and the brands that utilize this standard. [1] News reports are duly reporting that consumers should only purchase USP-verified Vitamin D. (12) But the data in the study did not justify that conclusion, so those news reports were based on inaccurate information and are therefore wrong.
The authors claimed that “the Food and Drug Administration [FDA] does not regulate vitamin D supplements.” 1 This is simply not true. [2] The FDA does indeed regulate all dietary supplements, including Vitamin D. 2 A summary of dietary supplement regulation is posted on that agency’s website. [3], 9 There are also various third-party summaries of current dietary supplement regulation available. [4], [5], [6], [7], [8], 10
The USP-verified OTC standards require a potency of 90% - 110% of the active label claim, as the authors point out. But this allows levels which are below the minimum required by the Dietary Supplement Health and Education Act of 1994 and the resulting FDA current Good Manufacturing Practices (cGMPs) that regulate supplement manufacturing and labels. The federal cGMPs require greater or equal to 100% potency; the capsules must at least match the label claims. This means that a product tested at 99% potency would be acceptable by the USP standards, but would not meet the FDA cGMP standards set in the regulations governing dietary supplements. This also means that a USP-Verified product could actually be deemed “misbranded” under these regulatory standards, and therefore illegal. So you can quickly see that the USP’s OTC (over the counter) drug standard is not applicable to dietary supplements. 10
In the letter published in that medical journal the authors reported that four of the 12 brands tested had samples that met the authors’ standards as being within their stated acceptable range of variance from label claim, yet only one of these was from a USP-verified company. Why was that brand singled out as superior when at least 3 other brands were within those same chosen (and as we discussed already, unacceptable) limits? And why did the authors specifically endorse that brand‘s certification program when admittedly one of the two USP-verified brand’s products tested actually failed this testing? 1 That’s a 50% failure rate, and the one USP-verified product that didn’t fail that standard still did not reliably meet the cGMP legal standard. To me, an experienced science writer, these inconsistencies of logic suggest a bias against the non-USP-verified brands and an unjustified conclusion that conveniently met the authors’ preconceived notions of dietary supplements being ‘unregulated’.
In this study, only 5 brands are USP-verified (Berkley & Jensen, Kirkland, Nature Made, Sunmark, TruNature). All are sold in mass market (Albertsons, BJ’s Wholesale Club, Costco, CVS, Eckerd, Giant, Health Mart, Hy-Vee, K-Mart, Kroger, Long’s, Osco Drug, Ralph’s, Rite-Aid, Safeway, Sam’s Club, Stater Bros, Super Valu, Target, Valu-Rite, Walgreen’s), not health food stores. [9] Brands sold in the natural products channel (health food stores) typically don’t verify their products to the non-compliant USP standards. Most good natural products brands are certified by different 3rd party organizations that certify their compliance to the FDA’s cGMP standards, which are the law of this land. [10], [11] We don’t know if any of the brands tested were third-party certified by these other organizations because the authors did not disclose those brands or discuss any other claims of third-party certification. 1
Why do people buy vitamins at health food stores instead of drug stores in the first place? Many people reject some of the pharmaceutical ingredients that are commonly used in products sold in that channel but which are not used in vitamin products sold in the natural channel. These questionable ingredients include petroleum and coal tar derivatives, talc, hydrogenated oil, artificial colors/flavors/sweeteners, crospovidone, butylated hydroxytoluene, and hypromellose.
The moral of this story is “don’t accept everything you read,” even if published by well-credentialed scientists in a “prestigious” scientific journal and dutifully reported by well-meaning news organizations. Under U.S. law, USP-Verified is not an acceptable standard for dietary supplements because its standard fails to meet the legal requirements for dietary supplements. Instead, look for dietary supplements that are third-party GMP-certified in order to assure that your vitamins are manufactured under proper conditions to assure safety and efficacy, and are properly tested to meet 100% of label potency as required by law.
REFERENCES (links accessed Feb. 18, 2013)
