Understanding Nutrient Labeling for Dietary Supplements (and Foods)
If you read or heard that 32% of multivitamin-mineral supplements failed to pass laboratory standards, you shouldn’t be too worried. The report finds that most products are properly labeled. In reality, fewer than 32% are mislabeled. Why?
The law dictates that supplements (and foods) must contain the labeled amount of nutrients at the end of its shelf life. Prior to the best buy date, percentages on a nutrition facts label may not agree precisely with laboratory analyses for two reasons: 1) product under delivers claimed amount of a vitamin, or 2) product over delivers. Both situations are not necessarily a cause for concern.
1. Because the FDA recognizes there is variability in the manufacturing process, the law states “The percentages for vitamins and minerals shall be expressed to the nearest 2-percent increment up to and including the 10-percent level, the nearest 5-percent increment above 10 percent and up to and including the 50-percent level, and the nearest 10-percent increment above the 50-percent level.” To rephrase, label claims on food and supplement products providing more than 50% of the Daily Value (DV) may differ from analytical determinations by ≤10%. If a supplement has 8% less than label claim, the product is correctly labeled according to the law.
2. Many vitamins will degrade when exposed to heat, moisture, oxygen, light or acidity. Vitamins A, C and E are particularly reactive. Because of stability concerns, extra vitamins (overages) are added during manufacturing to ensure the supplement (food) meets label claims at the end of shelf life. When products don’t meet label claims by the end use date, i.e. fall within 10% of vitamin claim in example above, then the product is improperly labeled. When the vitamin content of a supplement (or food) is analyzed long before the end of its shelf life, the vitamin content should be higher than the amount stated on the Nutrition Facts panel. Laboratory analysis should find supplements (and foods) containing more than the label claim of ‘unstable vitamins’ early in their shelf life. This is NOT an indicator of concern, it is responsible manufacturing.
Two-thirds of U.S. adults use multivitamins and other dietary supplements. Ninety percent report using them to improve nutrient intakes. Multivitamin-mineral supplements have a long history of use. Although some products may not be manufactured to high-quality standards, these are infrequent. Don’t be dissuaded by headlines trying to incite readers.
Dickinson A, MacKay D, Wong A. Consumer attitudes about the role of multivitamins and other dietary supplements: report of a survey. 2015 Nutr J doi: 10.11186/s12937-015-0053-9
Dickinson A, Blatman J, El-Dash N. Consumer usage and reasons for using dietary supplements: report of a series of surveys. 2014 J Am Coll Nutr doi: 10.1080/07315724.2013.875423