title: Analytical ingredient content and variability of adult multivitamin/mineral products: national estimates for the Dietary Supplement Ingredient Database.
abstract: Multivitamin/mineral products (MVMs) are the dietary supplements most commonly used by US adults. During manufacturing, some ingredients are added in amounts exceeding the label claims to compensate for expected losses during the shelf life. Establishing the health benefits and harms of MVMs requires accurate estimates of nutrient intake from MVMs based on measures of actual rather than labeled ingredient amounts.
  
  
  
  Our goals were to determine relations between analytically measured and labeled ingredient content and to compare adult MVM composition with Recommended Dietary Allowances (RDAs) and Tolerable Upper Intake Levels.
  
  
  
  Adult MVMs were purchased while following a national sampling plan and chemically analyzed for vitamin and mineral content with certified reference materials in qualified laboratories. For each ingredient, predicted mean percentage differences between analytically obtained and labeled amounts were calculated with the use of regression equations.
  
  
  
  For 12 of 18 nutrients, most products had labeled amounts at or above RDAs. The mean measured content of all ingredients (except thiamin) exceeded labeled amounts (overages). Predicted mean percentage differences exceeded labeled amounts by 1.5-13% for copper, manganese, magnesium, niacin, phosphorus, potassium, folic acid, riboflavin, and vitamins B-12, C, and E, and by ∼25% for selenium and iodine, regardless of labeled amount. In contrast, thiamin, vitamin B-6, calcium, iron, and zinc had linear or quadratic relations between the labeled and percentage differences, with ranges from -6.5% to 8.6%, -3.5% to 21%, 7.1% to 29.3%, -0.5% to 16.4%, and -1.9% to 8.1%, respectively. Analytically adjusted ingredient amounts are linked to adult MVMs reported in the NHANES 2003-2008 via the Dietary Supplement Ingredient Database (http://dsid.usda.nih.gov) to facilitate more accurate intake quantification.
  
  
  
  Vitamin and mineral overages were measured in adult MVMs, most of which already meet RDAs. Therefore, nutrient overexposures from supplements combined with typical food intake may have unintended health consequences, although this would require further examination.
authors.affiliation: Nutrient Data Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, USDA, Beltsville, MD; karen.andrews@ars.usda.gov.
authors.forename: Karen W
authors.initials: KW
authors.lastname: Andrews
authors.affiliation: Nutrient Data Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, USDA, Beltsville, MD.
authors.forename: Janet M
authors.initials: JM
authors.lastname: Roseland
authors.affiliation: Nutrient Data Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, USDA, Beltsville, MD.
authors.forename: Pavel A
authors.initials: PA
authors.lastname: Gusev
authors.affiliation: Nutrient Data Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, USDA, Beltsville, MD.
authors.forename: Joel
authors.initials: J
authors.lastname: Palachuvattil
authors.affiliation: Nutrient Data Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, USDA, Beltsville, MD.
authors.forename: Phuong T
authors.initials: PT
authors.lastname: Dang
authors.affiliation: Nutrient Data Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, USDA, Beltsville, MD.
authors.forename: Sushma
authors.initials: S
authors.lastname: Savarala
authors.affiliation: Nutrient Data Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, USDA, Beltsville, MD.
authors.forename: Fei
authors.initials: F
authors.lastname: Han
authors.affiliation: Nutrient Data Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, USDA, Beltsville, MD.
authors.forename: Pamela R
authors.initials: PR
authors.lastname: Pehrsson
authors.affiliation: Consulting Statistician, Longmont, CO.
authors.forename: Larry W
authors.initials: LW
authors.lastname: Douglass
authors.affiliation: Office of Dietary Supplements, NIH, Department of Health and Human Services, Bethesda, MD; and.
authors.forename: Johanna T
authors.initials: JT
authors.lastname: Dwyer
authors.affiliation: Office of Dietary Supplements, NIH, Department of Health and Human Services, Bethesda, MD; and.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Betz
authors.affiliation: Office of Dietary Supplements, NIH, Department of Health and Human Services, Bethesda, MD; and.
authors.forename: Leila G
authors.initials: LG
authors.lastname: Saldanha
authors.affiliation: Office of Dietary Supplements, NIH, Department of Health and Human Services, Bethesda, MD; and.|Department of Nutrition Science, Purdue University, West Lafayette, IN.
authors.forename: Regan L
authors.initials: RL
authors.lastname: Bailey
mesh_terms: D000328:Adult; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D018977:Micronutrients / Q000032:analysis*; D009749:Nutrition Surveys; D011786:Quality Control; D064167:Recommended Dietary Allowances; D015203:Reproducibility of Results; D014131:Trace Elements / Q000032:analysis*; D014815:Vitamins / Q000032:analysis*
chemical_list: D018977:Micronutrients; D014131:Trace Elements; D014815:Vitamins
keywords: NHANES; Recommended Dietary Allowance (RDA); US Pharmacopeia; dietary supplement; multivitamins; overage; quality control; reference material; sampling plan; upper limit