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ARS Home » Northeast Area » Beltsville, Maryland (BHNRC) » Beltsville Human Nutrition Research Center » Nutrient Data Laboratory » Research » Research Project #426694

Research Project: USDA Dietary Supplement Ingredient Database

Location: Nutrient Data Laboratory

2018 Annual Report


1a. Objectives (from AD-416):
The Dietary Supplement Ingredient Database (DSID) (http://dsid.usda.nih.gov; (U.S. Department of Agriculture, 2012) currently provides nationally representative supplement composition data for adult and children’s MVM, based on chemical analysis. All other dietary supplement databases contain label information only. In addition to the evaluation of vitamin and mineral levels in dietary supplements, the DSID will be expanded to include supplements with other ingredients of interest, including omega-3 (n-3) fatty acids in fish and plant oil supplements, and catechins, caffeine, and flavonoids in botanical supplements. Objective 1: Determine, evaluate, and expand knowledge about the composition of frequently consumed dietary supplements in the U.S. by collecting and compiling data and information on essential nutrients and emerging components of public health importance. This includes developing methods for sampling new dietary supplement product types, statistically evaluating analytical results to portray representative estimates, and improving the value of the Dietary Supplement Ingredient Database by utilizing new technologies to generate novel datasets.


1b. Approach (from AD-416):
Several types of studies are planned, including ongoing national and monitoring studies and new pilot and national studies. NDL will design and carry out research to analytically determine the ingredient composition of representative dietary supplements, including essential nutrients and bioactive components. NDL will identify laboratories for sample analysis and evaluate data quality. Results will be statistically evaluated and made publicly available through the DSID. On-going DSID Studies: 1) Omega-3 fatty acid national study: scientifically evaluate the relationships between labeled and analytical levels of omega-3 fatty acids in representative dietary supplements, including fish oil, plant oil and fish/plant oil blends. Release mean results and variability information from this study in DSID-3. 2) Over-the-Counter (OTC) prenatal MVM national study: scientifically evaluate the relationship between label and analytical values and assess the variability for up to 22 vitamins and minerals in OTC prenatal MVM. Release mean results and variability information from this study in DSID-3. 3) Adult MVM monitoring study: systematically evaluate the statistical relationships between label and analytical data since the first adult MVM study in a monitoring study of adult MVM, and release results in DSID-4. The information from this study will be used to plan the frequency and scope of updates to DSID for other MVM and possibly other supplement categories. Pilot Studies: 1) Green tea study AND flavonoid-containing dietary supplements (DS) study: methods of analysis will be evaluated by testing representative and top-selling products for prioritized ingredients of interest. 2) Calcium in DS and OTC antacids study: DS and OTC antacids, a major source of supplemental calcium intake in the U.S., will be assessed for their calcium and vitamin D content. National Studies: 1) Green tea DS and flavonoid-containing DS studies: obtain mean estimates for and measures of variability for analyzed catechins, caffeine, and for analyzed flavonoids (such as flavonols, flavones, flavanones, catechins, and anthocyanidins) in nationally representative botanical DS. 2) Calcium in DS and OTC antacids study: determine national estimates for ingredients in calcium-containing DS, a commonly reported supplement


3. Progress Report:
Objective 1: Determine, evaluate, and expand knowledge about the composition of frequently consumed dietary supplements in the U.S. by collecting and compiling data and information on essential nutrients and emerging components of public health importance. We researched the potential impact of DSID adjustments for labeled ingredient content on intake calculations. We calculated the percentages of adult (first and second DSID studies), children’s and nonprescription prenatal MVMs, and omega-3 fatty acid supplements in the NHANES database affected by the DSID predicted overages or below label-ingredient content. Ingredients with >20% overages and with more than half of the NHANES products affected are iodine and selenium in adult MVM-1; chromium, folic acid, iodine, selenium, vitamin A, vitamin B-12 and vitamin D in adult MVM-2; iodine and vitamins D and E in children’s MVM; and chromium, iodine, and potassium in nonprescription prenatal MVM. Ingredients with overages of 10–20% applied to more than half of NHANES products are calcium, folic acid, and riboflavin in adult MVM; copper, phosphorus and riboflavin in adult MVM-2; calcium, folic acid, vitamin A, vitamin B-12, and vitamin B-6 in children’s MVM; and calcium, selenium, and vitamin D in nonprescription prenatal MVM. DSID overages of 10–20% for calcium are predicted for all MVM (except adult MVM-2) and >10% overages are predicted for folic acid in the vast majority of adult and children’s MVM. Ingredients with content predicted to be below label and with more than half of NHANES products affected are thiamin in adult MVM-1; magnesium and thiamin in adult MVM-2; and niacin, thiamin, vitamin B-6, and zinc in nonprescription prenatal MVM, and EPA in omega-3 fatty acid supplements. A majority of MVM reported in NHANES have significant overages for several ingredients. It is important to account for non-labeled additional nutrient exposure from DS to better evaluate nutritional status in the United States. The intake of some under-consumed nutrients, such as calcium and vitamin D, may be underestimated if DSID adjustments to label claims are not applied. For children’s MVM, we compared product label and analytical content to RDA, UL, and market shares. For 13 of 16 nutrients (such as copper, iodine, iron, zinc, folic acid, niacin, riboflavin, thiamin, vitamin A, B-12, B-6, D, and E), most MVM were labeled at or above the RDA levels for 8 year old children (excluding calcium, magnesium, phosphorus which were labeled below the RDA in all tested products). The products with the four nutrients that were labeled above their UL (zinc, folic acid, niacin and vitamin A) had overall mean market shares comparable to the products labeled within RDA-UL ranges. During manufacturing, many companies intentionally add higher than claimed ingredient levels in order to compensate for losses during the shelf life, and this practice probably contributed to the overages measured in children’s MVM. MVM intake may be combined with the intake of highly fortified foods, and this raises safety concerns if the UL are exceeded. Therefore children’s MVM may lead to overexposure at the population level and they may be a concern for individual consumers as little is known about high dose long-term effects of these micronutrients in children. NHANES 2003-2006 data indicated that although DS use reduced the percentage of children (2-18) below the EAR for calcium, magnesium, zinc, phosphorus, and vitamins A, C, D and E, it also increased the percent of children whose intakes exceeded ULs for iron, zinc, copper, folic acid and vitamin A (retinol). Twenty-four prescription (Rx) prenatal MVM in 2 lots (some of the products sold as packs containing different dosage forms: soft gels, tablets, caplets) are being tested for their chemical content and evaluated against labeled levels for folic acid, iodine, other vitamins and minerals and docosahexaenoic acid. They are also being tested for disintegration and dissolution. The efficacy of an oral dosage form is determined not by only by the active ingredient amount but also by formulation design. A formulation design may greatly influence the amount of the ingested ingredient that is absorbed, how much reaches the target site within a defined period of time, and, ultimately, health benefits for the users. United States Pharmacopeia (USP) develops performance standards such as in vitro disintegration and dissolution tests to detect problems with active ingredient release from dosage forms. Disintegration testing demonstrates how a tablet or capsule breaks apart under specific controlled conditions within an allotted time. Noncompliance with the USP standards may impact the release of active ingredients from dosage forms after swallowing. The USP standards are obligatory for drug but not for DS manufacturers. Rx prenatal MVM are not categorized as drugs by the FDA but as DS. Also, in contrast to drugs which are largely single-ingredient formulations, the vast majority of DS have multi-ingredient content that requires careful selection of USP testing protocols. Agitation parameters, destructive forces (disk or no disk in basket), pre-soaking and medium composition, temperature and pH are adjusted to specific formulation categories. USP suggests using the less harsh conditions if several ingredients require different testing conditions but with differences in more than one parameter, the less harsh condition may not be easy to identify. We applied tests with increasing destructiveness (in our judgment) to products that failed to disintegrate under less harsh conditions to evaluate their impact. All 13 tested Rx prenatal MVM in the form of soft gels passed the rupture disintegration test in two lots. When a disk was included in the disintegration test, 13 tablets out of 19 passed the test in lot #1, and 12 out of 16 in lot #2. Pre-soaking helped to disintegrate some products that initially failed: at least 84% of 19 tested Rx tablets met the USP disintegration standards that include the harshest conditions (use of disk after pre-soaking). Since it is not clear what protocol has harsher conditions, these results are not yet conclusive. DS consumers may benefit from DS performance standardization similar to pharmaceuticals but for some products conclusive results may not be obtained when USP guidance could be interpreted in several ways. To select appropriate protocols for testing, more detailed USP methods are needed. Also, harmonization is needed between the information available on DS labels and that required for USP testing. In our study evaluating whether single-ingredient green tea DS (GT-1) met the USP 40 general chapter specifications for dissolution, we concluded that the initial medium filtering procedure did not take into account EGCG binding to nylon filter membranes. A dissolution test measures the amount of marker compound (in this case, epigallocatechin gallate; EGCG) released from a dosage unit into a stirred solution at a specified time. In its initial design, none of the 24 GT-1 DS tested for dissolution passed the test. However, a series of 4-10 ml filter pre-flushes with EGCG solutions were not sufficient to saturate the nylon filter and to avoid EGCG loss. We concluded that use of nylon filters is unacceptable, and only polytetrafluoroethylene (PTFE) filters should be used for EGCG measurements. We tested a new, fourth, lot for 11 products with PTFE filters. Four (50%) of 8 products with gelatin capsules passed the test (pH 1.2). One out of 3 products in non-gelatin (pullulan made) capsules passed the test. Ten products were not retested because they did not disintegrate in the initial dissolution experiments and released less than 6% of their EGCG. Thus, a newly-measured success rate for single-ingredient green tea DS is 5 (20.8%) of 24 products (23 capsules, 1 tablet). For capsules, the pass rate is higher for products with gelatin capsules as compared to non-gelatin-based capsules: 4 out 9 (44.4%) vs. 1 out 14 (7.1%; including an in-house control). For our next step, we will use pepsin to overcome potential crosslinking in the failed gelatin capsules. Disintegration pass or fail performance is consistent for multiple (4) lots for some GT-1 DS (n=5) while others are inconsistent in quality in monitored lots (over 4 years, n=5). DS with inconsistent disintegration and impaired dissolution in the USP tests raise concerns about the amounts of EGCG available for absorption and microbial transformation in the gastrointestinal tract among different lots of the same DS and among different brands. Because testing of ingredient release from DS dosage forms in vivo is not required by the FDA regulations, development and application of in vitro tests that better predict ingredient release in the GI would be highly beneficial for consumers seeking to improve their health with DS use. The analytical results on catechins and caffeine content in multi-ingredient GT DS (2 lots, n=32) were prepared for statistical analysis. Two lots of 50 DS with turmeric as the only or primary ingredient are currently being tested for their content of curcumin, demethoxycurcumin and bisdemethoxycurcumin, and black pepper extracted piperine (added to improve bioavailability). Immediate release forms that are hard/soft shell capsules or tablets are being tested for disintegration. 2 lots of 25 DS with cranberry as the only ingredient (as dried cranberry powders or fruit extracts) in immediate release forms in capsules or tablets are also being tested for disintegration.


4. Accomplishments
1. Many green tea dietary supplements fail performance testing. The United States Pharmacopeia (USP) develops performance standards aimed to detect problems with active ingredient release from dosage forms that may occur due to formulation design and manufacturing processes. Meeting these specifications also ensures that different batches of products would release active ingredients consistently. In the U.S., meeting the USP standards is mandatory for drugs but not for dietary supplements. We evaluated whether commercially sold single- and multi-ingredient green tea met the USP general chapter standards for disintegration of 29 single-ingredient products tested, 16 passed, 12 failed and 1 performed inconsistently in the disintegration testing. Of 36 multi-ingredient products, 21 passed, 10 failed, and 5 exhibited inconsistent performance. Only 5 out 24 single-ingredient dietary supplements passed the dissolution test. We established significant disparity in performance quality among commercial green tea supplements. Compliance with the USP standards for DS is currently voluntary.