FREQUENTLY ASKED QUESTIONS (FAQ)
Many answers to your questions can be found by clicking the DSID web links to access various parts of the web site. Responses to frequently asked questions (FAQs) are below.
DSID Development
2. Why was the Dietary Supplement Ingredient Database created?
3. What data and formats does the DSID-1 provide?
5. What agencies have collaborated to develop the DSID?
Data Terms and Explanation
6. What is the “Predicted Value”?
7. What are the “Standard Error for Predicted Mean” and the “Standard Error for Predicted Observation”?
8. How were the “Predicted Value”, “Standard Error for Predicted Mean” and “Standard Error for Predicted Observation” calculated?
9. How were the predicted calculations developed?
10. What’s the difference between milligram (mg), microgram (mcg), and International Unit (IU)?
11. How can I convert ‘mg’ to ‘IU‘ and vice-versa?
Applying the Data
12. For what dietary supplements can these predictions be used?
13. How can these predicted values be used in nutrition studies?
14. How do I know what amount of each nutrient I need each day?
Technical Questions
15. What are the computer requirements to use the DSID-1 data files?
16. How is the term “serving size” used in DSID research?
The DSID, the Dietary Supplement Ingredient Database, an initiative of the Office of Dietary Supplements at NIH, was developed at the Nutrient Data Laboratory, US Department of Agriculture. DSID-1,the first release of DSID, provides access to information on estimated levels of ingredients in adult multivitamin/mineral (MVM) products. DSID research has focused first on priority ingredients in MVMs, since these products are the most commonly consumed dietary supplements in the United States
2. Why was the Dietary Supplement Ingredient Database created?
The Dietary Supplement Ingredient Database (DSID) was created to: a) develop reliable estimates of ingredients and other bioactive components in dietary supplement (DS) products; (b) support improved dietary intake assessments in research by providing analytical estimates of the ingredient content of marketed dietary supplements; (c) report on analyzed levels of ingredients relative to labeled values; and (d) release and maintain a publicly available on-line composition database. By using data in the DSID, analytically-based estimates of nutrient content of adult multivitamin/minerals (MVMs) can be combined with supplement intake records to estimate total nutrient intake from food plus supplements. These estimates can assist researchers to make more accurate quantitative intake assessments and evaluate the nutritional status of Americans.
3. What data and formats does the DSID-1 provide?
The DSID-1 provides estimated amounts for 18 vitamins and minerals for a wide range of labeled levels of these nutrients in adult MVMs. A variety of files and formats are provided. The DSID-1 includes: a) Regression equations; b) Data file containing predicted ingredient amounts; c) Data files containing DSID applications to adult MVM products in the National Health and Nutrition Examination Survey (NHANES), for the 2003-04 and 2005-06 surveys; d) List of DSID-1 ingredients and units; e) Research summary (.pdf document); f) Adult MVM calculator.
A consortium of federal partners convened by the Office of Dietary Supplements established DSID priorities for products and ingredients of public health and research interest. Adult MVM products were identified as a top priority because they are the most commonly reported dietary supplement in the National Health and Nutrition Examination Survey (NHANES). The vitamins and minerals for analysis were determined based on prevalence of consumption, public health interest, and the availability of reliable analytical methods for specific compounds.
5. What agencies have collaborated to develop the DSID?
Collaborators for the DSID project include:
- DHHS, NIH, Office of Dietary Supplements: http://dietary-supplements.info.nih.gov/
- USDA, ARS, Food Composition Laboratory http://www.ars.usda.gov/main/site_main.htm?modecode=12-35-15-00
- DHHS, Centers for Disease Control, National Center for Health Statistics http://www.cdc.gov/nchs/Default.htm
- DHHS, U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition http://www.cfsan.fda.gov/~dms/supplmnt.html
- DOC, National Institute of Standards and Technology http://www.nist.gov/
6. What is the “Predicted Value”?
The “predicted value” is the estimated amount of that ingredient based on the labeled amount, as determined by statistical regression analysis. Predicted values at common labeled levels for adult MVMs are based upon the ingredient amount per serving, using the labeled serving size. Statistical parameters have been established within a defined regression range for each nutrient. For example, the defined regression range for making predictions for vitamin C includes labeled levels from 4 to 1000 mg. For labeled levels above and below those amounts, predicted amounts are not available.
The “standard error for the predicted mean” is the standard deviation of a sampling distribution of means, calculated in this study by dividing the standard deviation by the number of analytical values. This is the error associated with the predicted mean for a large population of supplements labeled at the same level. The “standard error for predicted observation” estimates the error associated with the predicted mean for a single new observation, which in this case is any individual adult MVM supplement product. The “predicted value” is the estimated amount of that ingredient based on the labeled amount, as determined by statistical regression analysis. Predicted values at common labeled levels for adult MVMs are based upon the ingredient amount per serving, using the labeled serving size. Statistical parameters have been established within a defined regression range for each nutrient. For example, the defined regression range for making predictions for vitamin C includes labeled levels from 4 to 1000 mg. For labeled levels above and below those amounts, predicted amounts are not available.
8. How was the prediction calculations developed?
The data used in the prediction calculations were derived from a nationwide adult MVM study conducted during 2006 to 2008 to determine nutrient values for representative adult MVM products (n > 2 vitamins). Thirty-five commonly reported adult MVMs and 75 lower market share products were purchased in six geographic locations from various market channels and analyzed for 18 nutrients at qualified laboratories. Results from this study were statistically evaluated using regression analysis. Detailed information about the study is available in the research summary report, which can be accessed and downloaded from this web site.
These values were calculated from regression equation information provided in Table 1 of the DSID-1 release. Also provided is an example document, providing equations and instructions for applying the data in table 1 to labeled levels for adult MVM supplement products.
10. What’s the difference between milligram (mg), microgram (mcg), and International Unit (IU)?
As metric units of measurement to quantify weight, 1000 micrograms (mcg) equal 1 milligram (mg). An IU (International Unit) is a unit of measurement for vitamins and other specific biologically active substances. The equivalency of one IU differs from substance to substance and is established by international agreement for each substance. For instance, one IU of vitamin E does not contain the same number of milligrams as one IU of vitamin D. In addition, vitamin E exists in a number of different forms having different biological activities. Rather than specifying the precise type and mass of vitamin E in a supplement, the Supplement Facts label specifies the number of International Units of vitamin E which is based upon what form of vitamin E has been used as an ingredient. The equivalents of 1 IU for selected vitamins are: Vitamin A: 1 IU is the biological equivalent of 0.3 µg retinol, or of 0.6 µg beta-carotene; Vitamin D: 1 IU is the biological equivalent of 0.025 µg cholecalciferol/ergocalciferol; Vitamin E: 1 IU is the biological equivalent of 0.9 mg dl-alpha-tocopherol; or 0.67 mg of d-alpha-tocopherol.
11. How can I convert ‘mg’ to ‘IU’ and vice-versa?
- From IU to mcg: IU*0.3 = mcg
- For example: 5000 IU*0.3 = 1500 mcg
- From mcg to IU: mcg/0.3 = IU
- From IU to mcg: IU*0.6 = mcg
- From mcg to IU: mcg/0.6 = IU
- From IU to mcg: IU*0.025 = mcg
- For example: 400 IU*0.025 = 10 mcg
- From mcg to IU: mcg/0.025 = IU
- From IU to mg: IU*0.9 = mg
- For example: 30 IU*0.9 = 27 mg
- From mg to IU: mg/0.9 = IU
- From IU to mg: IU *0.67= mg
- For example: 30 IU*0.67 = 20.1 mg
- From mg to IU: mg/0.67= IU
12. For what dietary supplements can these predictions be used?
Predicted amount per serving information is based upon data for adult multivitamin/mineral (MVM) products only. MVMs in this study are dietary supplements containing three or more vitamins, the definition used by the National Center for Health Statistics (NCHS).
13. How can these predicted values be used in nutrition studies?
DSID can support surveys that estimate nutrient intake contributed by dietary supplements. For example, scientists can compare predicted values with label values to assess the magnitude of the difference for application to individual studies. Analytically-based estimates of nutrient content of MVMs using DSID data can be combined with supplement intake records to estimate total nutrient intake from food and supplements. These estimates can assist researchers to make more accurate quantitative intake assessments and evaluate the nutritional status of Americans.
14. How do I know what amount of each nutrient I need each day?
Please refer to Dietary Reference Intake (DRI) guidelines from the Institute of Medicine (IOM): http://www.iom.edu/Object.File/Master/21/372/0.pdf - (Accessed April 2009)
For information about % Daily Values, please refer to guidelines from the Food and Drug Administration (FDA): http://www.cfsan.fda.gov/~dms/2lg-xf.html - (Accessed April 2009)
15. What are the computer requirements to use the DSID-1 data files?
For the best viewing, set your computer monitor’s screen resolution to 1024 x 768 pixels as follows: Left-click start, then control panel, then double-click on display. Under the settings tab, select the screen resolution section. Both Internet Explorer versions 6 and 7 can be used to view web content on the DSID-1 website. DSID-1 data files are compiled using version 2003 of Microsoft Word, Excel, and Access. If viewing is difficult after making these adjustments, contact your technical staff.
16. How is the term “serving size” used in DSID research?
DSID data are reported in “per serving” amounts. “Per serving” is the common term used on the Supplement Facts label to indicate the number of units (tablets, capsules, gel caps, etc) recommended to consume per occasion. The serving size is product-specific, and may be one or more units. Data are reported as nutrient amounts per serving in the DSID-1 release.
