Characteristics and Challenges of Dietary Supplement Databases Derived from Label Information

Abstract

Launched in 2008, the Dietary Supplement Label Database (DSLD) permits the search of any term that appears anywhere on product labels. Since then, the database's search and download features have been periodically improved to enhance use for researchers and consumers. In this review, we describe how to customize searches and identify products and ingredients of interest to users in the DSLD, and provide the limitations of working with information derived from dietary supplement product labels. This article describes how data derived from information printed on product labels are entered and organized in the DSLD. Among the challenges are determining the chemical forms, types of extract, and amounts of dietary ingredients, especially when these are components of proprietary blends. The FDA announced new dietary supplement labeling regulations in May 2016. The 2017 DSLD has been updated to reflect them. These new regulations and examples cited in this article refer to this redesigned version of the DSLD. Search selection characteristics such as for product type and intended user group are as described in FDA guidance and regulations for dietary supplements. For this reason, some age groups (such as teens and seniors) and marketing recommendations for use (e.g., weight loss, performance, and other disease- or condition-specific claims) are not included in the search selections. The DSLD user interface features will be revised periodically to reflect regulatory and technologic developments to enhance user experience. A comprehensive database derived from analytically verified data on composition would be preferable to label data, but is not feasible for technical, logistic, and financial reasons. Therefore, a database derived from information printed on product labels is the only practical option at present for researchers, clinicians, and consumers interested in the composition of these products.

Background

The Dietary Supplement Health and Education Act of 1994 (DSHEA) defined a dietary supplement as a product made up of dietary ingredients (1). A “dietary ingredient” is defined as “any one of the following: (a) a vitamin; (b) a mineral; (c) an herb or other botanical; (d) an amino acid; (e) a dietary substance for use by man to supplement the diet by increasing the total dietary intake; or (f) a concentrate, metabolite, constituent, extract, or combination of any ingredient described in (a), (b), (c), (d), or (e)”. Examples of ingredients that belong in each of these categories are provided in the FDA draft New Dietary Ingredient notifications guidance for industry (2). A dietary supplement is limited to products that can be ingested as a tablet, capsule, powder, softgel, gelcap, or liquid form. Also, a dietary supplement cannot be represented as a conventional food or as the sole item of a meal or of the diet, and must be labeled as a dietary supplement.

DSHEA also created dietary supplements as a new subcategory of foods and gave the FDA the authority to draft new regulations that applied only to dietary supplements. Consequently, although some dietary supplement labeling regulations have characteristics in common with those for conventional foods, many are quite different. Figures 1 and 2 compare the labels for a food and for dietary supplements that comply with the labeling regulations published in May 2016 (3, 4). Differences include ingredients that can be listed within the Supplement Facts box, how they can be listed, their common names, and the types of claims that can be made about their benefits. Ingredients that do not have daily values (DVs), such as botanicals, can be listed within the Supplement Facts (but not within the Nutrition Facts) box, and physical forms commonly associated with drug products, such as tablets and capsules, are permitted for dietary supplements, and not associated with foods. DSHEA also permitted the use of structure/function claims for non-DV dietary ingredients, accompanied by the disclaimer statement, “This statement(s) has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.” Structure/function claims can be general well-being claims, or they can describe how a dietary ingredient is intended to affect the normal structure or function of the human body, or act to maintain such structure or function. These types of claims (for non-DV ingredients) are not permitted on conventional food packages. These factors are relevant when developing dietary supplement databases under the auspices of the Federal government.

FIGURE 1.

Example of a food label that includes mandatory and some voluntary nutrients that complies with the May 2016 labeling regulations. Reproduced from reference 3.

FIGURE 2.

Examples of dietary supplement labels showing options for listing dietary ingredients that comply with the May 2016 labeling regulations. (A) Example of a dietary supplement label that includes a proprietary blend of dietary ingredients. (B) Example of a dietary supplement label that includes multiple vitamins and the voluntary listing of vitamin D in IUs and folate as folic acid. (C) Example of a dietary supplement label that includes multiple vitamins for children and adults (excludes Servings per Container, which is stated in the net quantity of contents declaration). Reproduced from reference 4.

Rationale

This article illustrates the richness of information contained in the 2017 Dietary Supplement Label Database (DSLD) and both the benefits and limitations in working with data derived from product labels (5). This 2017 DSLD (described in greater detail under “Recent developments”) has been redesigned to be more user-friendly and reflect technologic developments. The 2017 DSLD also incorporates changes in dietary supplement labeling that are consistent with the 2016 labeling regulations, such as the updated DVs (6, 7). Labels in the DSLD are sourced primarily through a program where manufacturers submit labels on a periodic basis to the group that curates the database. The DSLD also sources labels that are used in national surveys, such as National Health and Nutrition Examination Surveys (NHANES), and labels that various Federal agencies would like to see incorporated in the database.

In this article, we discuss the results of DSLD searches with 3 examples representing different types of supplements. The examples are iron (a mineral), DHA (a fatty acid categorized under DSHEA as a dietary substance to supplement the diet by increasing total dietary intake, since fats are not singled out specifically in the legal definition of a dietary supplement), and Amazonian palm fruit (acai, Euterpe oleracea) (an herb or other botanical). Only 1 of the 3 examples, iron, is a nutrient that has a DV. There is no DV for DHA, even though it is a nutrient, and acai does not have a DV because it is an herb; however, because they are dietary ingredients, they can be listed within the Supplement Facts box but not within the Nutrition Facts box. The amounts shown in Table 1 were compiled from data obtained via the search and download features located under Search Ingredients in the DSLD.

TABLE 1.

Information in the DSLD for iron, DHA, and Amazonian palm fruit (acai)¹

	Iron	DHA	Amazonian palm fruit (acai)
Information on ingredients using ingredient search
Labels in DSLD (currently on-market), n	4375	2016	712
Synonyms of ingredient listed on labels, n	42	47	95
Listed the amount on labels, %	75	89	26
Range of amounts listed (all forms)	<0.1–325 mg	1–1650 mg	0.01–30,000 mg
Characteristics of product(s) containing the ingredients using the category codes (LanguaL): type of supplement
Combination with other categories of dietaryingredients, %	96	45	84
Non-combination product, %	4	55	16

¹The numbers presented in the table are for products listed as on-market in the DSLD in June 2017. Of the >65,000 labels in the DSLD, ∼47,000 were on-market; the remainder were discontinued products. DSLD, Dietary Supplement Label Database.

Description

Determining the form(s) of a dietary ingredient

Knowing the chemical form of a dietary ingredient used in a supplement may be important to a researcher who is designing a clinical trial, comparing product formulations with clinical trial outcomes, or analyzing products to verify label claims (8, 9). However, this can be challenging if information on the different chemical compounds and their bioavailability or conversion factors from precursors to the active constituents is not available, especially for botanicals. It is also problematic when the labels of proprietary blends do not provide enough information to arrive at this calculation.

Figure 2 shows how dietary ingredients can be listed within the Supplement Facts box so that they comply with the regulations introduced in May 2016 (4, 10). These label examples will help explain the DSLD search results. The FDA gives dietary supplement manufacturers considerable flexibility in how they can list dietary ingredients within the Supplement Facts box. Figure 2A shows that the listing of the total amount of a proprietary blend of botanical ingredients, but not the individual amounts within the proprietary blend, is permitted. Figure 2B shows the listing of the common names along with the chemical forms of vitamins, and the alternate listing of the amounts of vitamin D in IU and folate in μg folic acid. Figure 2C shows the listing of amounts for more than one intended user group, such as adults and children, along with the chemical forms of vitamins listed as other ingredients (outside of the box).

The same ingredient may be identified by many names on supplement labels. Table 1 shows that there were 42 synonyms for iron, 47 for DHA, and 95 for acai on labels in the DSLD. In the case of iron, the 42 synonyms were primarily the different chemical forms of iron, which can be listed within the Supplement Facts box (such as iron from iron protein succinylate or ferrous gluconate or ferrous sulfate). In the case of DHA, it can be listed as the form (powder, oil), the source (algal), or as a component of a blend (omega-3 DHA), or it can be listed with the proprietary name of the ingredient. However, in the case of acai, the forms may be listed in a variety of ways (as fruit, juice, powder, extract), or as a combination of these forms and their concentrations.

Determining the amount(s) of a dietary ingredient

Researchers often want to calculate total intakes of nutrients (such as the amount of elemental iron provided from both food and supplement sources), and therefore it is important to be able to do this from dietary supplements. Caution is indicated, because although the amount listed on supplement labels often is the amount of elemental iron, it can also be simply the amount of the salt or ingredient, even though the FDA requires the labeled amount to be the elemental mineral or freeform vitamin. Compared with the situation for conventional foods, the FDA gives dietary supplement manufacturers more flexibility on how they can list the amounts of dietary ingredients within the Supplement Facts box. A dietary ingredient can be listed as a component of a proprietary blend without listing the amounts of the individual ingredients within the proprietary blend; or in the case of vitamins and minerals, the amount and source can be listed and the alternate listing of amounts is permitted, using units that comply with 2016 and 1990 labeling regulations, e.g., μg and IU for vitamin D (see Figure 2) (4, 10). The compliance date for the new regulation is 26 July 2018, to 1 January 2020 for manufacturers with $10 million or more in annual food sales, or 1 January 2021 for manufacturers with <$10 million in annual supplement sales. Until then, the labels can comply with regulations that were issued before May 2016 (11). The format of the Supplement Facts label will not change substantially and only products that contain dietary ingredients with DVs will be affected. The labels of products that do not contain added sugar or any dietary ingredients with DVs, such as an herb or other botanical, concentrate, metabolite, constituent, or extract, will not be affected by the recent regulations. Changes to product labels because of the recent labeling regulations are described under the “Help Menu” in the DSLD.

Table 1 also shows that our DSLD search yielded 4375 products that listed iron on the label. Of these, 75% listed an amount on the label, with amounts ranging from <0.1 to 325 mg (all forms) per serving, and 25% either listed the amount as 0 or listed it as a percentage of the DV. Since iron is a commonly prescribed nutrient, some manufacturers use the USP (US Pharmacopoeia) designation and thus must comply with the appropriate USP monograph requirements (12). Consequently, a supplement using these monographs may list amounts as: 65 mg of elemental iron as ferrous sulfate or 200 mg of dried (anhydrous) ferrous sulfate, or 325 mg of ferrous sulfate (ferrous sulfate.7H₂O). Since conversion factors to the amount of elemental iron are available, converting the values listed to amounts of elemental iron can be accomplished via the Excel (Microsoft) downloaded file from the DSLD search.

Calculating the amounts is even more challenging for the non-DV dietary ingredients on supplement labels. For example, in our DSLD search for DHA products, 89% of the products in the database listed an amount on the label with amounts varying from 1 mg to 1650 mg, where 1650 mg is the amount of proprietary omega-3 blend rather than the amount of DHA. In contrast, our DSLD search for acai products showed that only 26% of the products listed the amount of acai on the label, with amounts ranging from 0.01 (extract) mg to 30,000 mg (juice). This makes it difficult to obtain total exposures, especially for constituents in botanicals of public health interest that are also in foods, such as caffeine. Because caffeine and caffeine sources are regulated as dietary ingredients their amounts can be listed inside the Supplement Facts box. In dietary supplements, caffeine can be added in the anhydrous form and/or as botanicals sources containing caffeine, e.g., green coffee bean extract, green tea extract, guarana, yerba mate, and kola nut (7, 13). Thus, if the natural form is used, the term and amount of caffeine may not appear on the supplement product label.

Using search filters to narrow search results

A researcher or practitioner may be interested in querying the database for a specific need, e.g., to identify supplements containing a given amount of ferrous sulfate for a clinical trial, or to identify supplements containing 400 μg of folic acid and 0 iron for a lactating woman, or to identify a supplement made by a specific manufacturer. The filters in Advanced Search permit users to customize their search and thus their search result. Although search filters for the type and amount of ingredient, brand name or manufacturer, type of claim(s), and defined category codes are available, the DSLD has limited searchability for fields such as intended user and claimed use because identifying the intended user or intended use is difficult as many products target multiple user groups and carry multiple claims. Further, these categories are not specified in FDA guidance.

Researchers, practitioners, and consumers are often interested in identifying products based on their claimed use, e.g., weight loss, performance enhancement, and other condition-specific claims. In the DSLD, products are not coded and categorized by these types of claimed uses, as these fall under the category of structure/function claims, for which there is no FDA permitted list. In addition, many product labels can carry more than one claim, making it difficult to identify and code the specific use. Since the DSLD permits the search of any term that appears anywhere on product labels, a user wanting to identify products marketed for a specific use can search for the specific words used in claims in the freeform text label statement or health claims search box.

In the DSLD, category codes based on the LanguaL thesaurus system are provided for the intended target group (user), product type, product form, and type of claim made on supplement labels (14, 15). A complete listing of these category codes is displayed in the drop-down menu in Advanced Search. LanguaL is a structured, controlled vocabulary for describing foods in a systematic organization that simplifies retrieval of information for data analysis. These codes are defined to be consistent with FDA regulations. Thus, in certain instances, such as products marketed for an intended target user group such as teenagers or seniors, the codes have limitations, since the FDA has not defined these user groups. For labeling purposes, the FDA has established only 4 sets of DVs: adults and children ≥4 y, children 1–3 y, infants 1–12 mo, and pregnant and lactating women. In establishing these DVs, the FDA selects the highest RDA value established by the National Academies of Sciences, Engineering, and Medicine's Food and Nutrition Board within each of these 4 age and condition groups (16). Based on these 4 groups, nearly all the products (98.4%) in the DSLD are labeled for adults and children ≥4 y (this includes teens and seniors), followed by children (0.9%), pregnant and lactating women (0.5%), and infants (0.1%).

Twelve product type category codes were created in LanguaL to be consistent with the regulatory definition of a dietary supplement (1). Examples of product type codes include vitamins only, minerals only, botanicals only, and multivitamin and mineral with botanicals (combination dietary ingredients). Researchers often are interested in whether a single ingredient or multiple ingredients of dietary supplements are responsible for the biological effects observed. Such questions were important in assessing the ill effects of ephedra supplements, which were banned from the market in 2004, and more recently of caffeine- and green tea–containing dietary supplements and energy drinks that appeared to be associated with cardiovascular abnormalities in some users (13, 17, 18). Additional codes were also created in DSLD for product categories/types commonly reported in NHANES such as single vitamin and single mineral (e.g., calcium and vitamin D) product, multivitamin and mineral with botanicals, and omega-3 supplements (15). For example, using the product type codes, only 4% of the iron-containing products in the DSLD were in mineral-only products, and the remainder were coded as combination-ingredient products with other minerals, vitamins, and botanicals. In contrast, 55% of the DHA-containing products were coded as omega-3 or other fatty acid-only–containing products, and for the acai-containing products, 16% of them were coded as botanical-only products (see Table 1). Overall, 37% of all products in the DSLD were combination-ingredient products that did not include any of the other 11 defined product type categories. This finding illustrates the complexity of dietary supplements marketed in the United States.

Researchers need to be aware that many dietary supplements in the same product category may differ markedly from each other in both the number and amounts of added dietary ingredients (19). For example, the multivitamin and mineral supplement is the most commonly consumed supplement in the United States (20). However, in the DSLD, 2.9% of the products were solely multivitamin and mineral (i.e., containing ≥3 vitamins and minerals and no other dietary ingredient) and 11.4% were multivitamin and mineral with botanicals.

Dietary supplement matrices also vary widely, and these may affect not only the bioavailability of the ingredients they contain, but also the methods required for their analysis. Consumers may also prefer certain product forms, e.g., powders and soft-gel capsules, or gummies over tablets. Ten codes were created for product forms. Using these codes, in the DSLD, 48% of all products were in capsule form, followed by tablets (22%), powders (14%), and liquids (11%). All other forms made up 5% of the products; this includes 0.8% in gummy form.

Thus, if a practitioner were interested in finding vitamin C–containing products in liquid form for a toddler by using the search filters for vitamin C (ingredient search), and selecting vitamin-only products (category code A1302), intended target group ages 12 mo to 4 y (category code P0192), and liquids (category code E0165) under Advanced Search, the search would return 8 products in the database.

Recent Developments

Although the 2017 DSLD incorporates recent technologic developments to improve user interaction with the site, users need to recognize the limitations they might experience in working with the information. The 2017 DSLD is mobile-friendly, that is, it can be used on a variety of devices, from desktop computers to smartphones. The search and download features have been improved. For example, a quick-search feature is now available on the homepage, so users can more easily search the contents of the entire site. For searches in labels, ingredients, and manufacturers, recent technology is now being utilized to recognize and adjust for differences in user spelling and punctuation. In addition, downloadable content is now consistently presented in sortable, filterable tables with easy-to-recognize export buttons located above each table.

Although the DSLD provides enough information from supplement labels to permit consumers to know what each product contains, researchers who are using it for quantifying exposures to supplement ingredients need to be mindful of its limitations. The DSLD lists information as printed on dietary supplement labels, and because manufacturers have options on how to list the name of an ingredient, and the amount of that ingredient in various units, it may be difficult to calculate exact amounts. However, the DSLD contains calculators to convert the amounts to preferred units of measure. The DSLD also has filters that give users many options to customize their search results. Users can also download their search results to Excel, which permits them to edit and modify the results to meet their research needs. To arrive at more accurate estimates of intakes, researchers can also apply correction factors to label values available through the Dietary Supplement Ingredient Database (described elsewhere in this journal supplement) (21).

Users also need to be aware that there is significant heterogeneity in how the names and the amounts of dietary ingredients are presented in the DSLD, because the regulations afford supplement manufacturers considerable flexibility. US dietary supplement labeling regulations require that the common or usual names used for botanicals should be consistent with the standardized common names in the 1992 edition of Herbs of Commerce (8, 22). If there is no common name, or if the manufacturer opts not to use that name, the regulation requires that the Latin binomial name of the plant must be used instead. In 2003 the FDA issued a proposed rule to replace the 1992 edition of Herbs of Commerce with the 2000 edition (23, 24). Although this proposed rule has not been finalized, the FDA does not object to the use of the 2000 edition. However, there is not always complete agreement between the 1992 and the updated 2000 editions, as is the case with dietary supplements containing cinnamon (8, 25).

In addition to the use of common and usual names, US regulations also permit the use of proprietary names, and their use appears to be increasing on labels, both for ingredients and for ingredient blends. For example, there are 16 active trademarked names for curcuminoid blends on the US Patent and Trademark Office website (8, 26). The US Patent and Trademark Office grants a trademark if it is a unique name within a given application or use, but not if it is a unique product, such as chemical differences in the composition of the ingredients. The Office grants a patent for a unique product. Thus, the compositional differences in these blends are proprietary information held by the manufacturer, and are not available to the public.

Future Directions

It is intended that the DSLD will be periodically updated to reflect regulatory and technologic developments to enhance user experience with the database. Future modifications will address current limitations with the database, which reflect present characteristics of dietary supplement labels in the United States.

Conclusions

In summary, the DSLD is derived from information printed on dietary supplement labels. As with other label-derived food composition databases, the information entered in the database is not checked to ensure compliance with the FDA regulations, nor are the entries standardized to ensure consistency in the data displayed in the DSLD. In other words, what is in the database reflects what appears on the printed label and is currently permitted under US dietary supplement labeling regulations. As the 3 examples in this article illustrate, this can make it difficult to determine forms and amounts of dietary ingredients in products. As pointed out in other articles in this supplement, it is not feasible to create a verified database that contains all products marketed in the United States, because there is no official list of products and their sales volumes, nor are there testing procedures to analyze all ingredients. Even if this information were available, the cost of a comprehensive direct analysis database would be very high. However, at present, a database derived from information printed on product labels provides a workable option for researchers and other users interested in the composition of most dietary supplements sold in the United States.

Notes

Published in a supplement to The Journal of Nutrition. The Supplement Coordinator for this supplement was Johanna T Dwyer, Office of Dietary Supplements, NIH. Supplement Coordinator Disclosure: Johanna Dwyer is a contractor to the Office of Dietary Supplements, NIH and is employed to work in editing and preparing papers for submission; she has stock in several drug companies, some of which may sell dietary supplements, and has received partial travel and per diem costs for speaking at a symposium at the International Union of Nutritional Sciences (IUNS) meeting in a session sponsored by the International Alliance of Dietary Supplement Associations (IADSA) on content unrelated to this supplement. Publication costs for this supplement were defrayed in part by the payment of page charges. This publication must therefore be hereby marked “advertisement” in accordance with 18 USC section 1734 solely to indicate this fact. The opinions expressed in this publication are those of the authors and are not attributable to the sponsors or the publisher, Editor, or Editorial Board of The Journal of Nutrition.

JTD holds stock in several food and drug companies and served on the scientific advisory boards of Conagra Foods, McCormick Spices and as a consultant for Gerber/Nestle. She accepted partial travel and per diem expenses in 2017 to speak at a symposium on dietary supplements sponsored by the International Association of Dietary/Food Supplement Associations at the International Congress of Nutriton.

The study was funded by the Office of Dietary Supplements, National Institutes of Health.

Author disclosures: LGS, RAB, KWA, JWB, HFC, RBC, AGE, JG, CJH, and PMC, no conflicts of interest.

Abbreviations used: DSHEA, Dietary Supplement Health and Education Act of 1994; DSLD, Dietary Supplement Label Database; DV, Daily Value.