TABLE 3.
Product distribution by ingredient content compared with RDAs, with analytically measured mean percentage difference from label values and market shares1
| Group I: products labeled below maximum RDA |
Group II: products labeled within range from maximum RDA to maximum UL |
Group III: products labeled above UL |
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| Nutrient | Overall mean percentage difference from label | RMSE | Products,2 n | Overall mean percentage difference from label | RMSE | Products,2 n | Overall mean percentage difference from label | RMSE | Products,2 n |
| Calcium | 19.6 (−28 to 431) | 0.73 ± 1.65 | 81 | — | — | 0 | — | — | 0 |
| Copper | 55.9 (−15.4 to 319.3) | 0.20 ± 0.23 | 7 | 8.57 (−27.7 to 114.3) | 0.78 ± 1.74 | 72 | — | — | 0 |
| Iodine | 66.6 (10.6–207.4) | 0.25 ± 0.25 | 6 | 25.7 (−2 to 104) | 0.76 ± 1.82 | 63 | — | — | 0 |
| Iron | 4.3 (−21.6 to 17.1) | 0.29 ± 0.25 | 13 | 1.1 (−14.3 to 17.6) | 0.96 ± 2.03 | 37 | — | — | 0 |
| Magnesium3 | 3.6 (−6.5 to 32.7) | 0.79 ± 1.73 | 73 | — | — | 0 | −3.4 (−3.6 to −3.1) | 0.09 ± 0.01 | 2 |
| Manganese | 5.5 (−7.9 to 31.7) | 0.92 ± 2.13 | 46 | 7.18 (−5.7; 39.4) | 0.46 ± 0.56 | 31 | 18.2 | 0.12 | 1 |
| Phosphorus | 15.4 (−2.6 to 349) | 0.94 ± 2.11 | 46 | — | — | 0 | — | — | 0 |
| Potassium4 | 8.6 (−3.5 to 51.1) | 0.99 ± 2.1 | 46 | — | — | 0 | — | — | 0 |
| Selenium | 23 (−0.8 to 74) | 1.01 ± 2.23 | 42 | 25.2 (−41.2 to 64.2) | 0.42 ± 0.44 | 36 | — | — | 0 |
| Zinc | 10.4 (3.5 to 13.7) | 0.16 ± 0.16 | 7 | 4 (−4.7 to 22.8) | 0.76 ± 1.7 | 76 | −12.1 (−51.4 to 9.2) | 0.29 ± 0.31 | 3 |
| Folic acid | 20.1 (14.1 to 29.8) | 0.16 ± 0.04 | 3 | 13 (−23.4 to 66.8) | 0.69 ± 1.58 | 89 | 1.54 (−14.8 to 26.1) | 0.21 ± 0.22 | 8 |
| Niacin | 6.5 (−4.1 to 22.1) | 0.95 ± 1.24 | 6 | 2.3 (−39 to 21.2) | 0.8 ± 1.84 | 62 | −1 (−77.6 to 23.7) | 0.25 ± 0.25 | 30 |
| Riboflavin4 | 80 (−6.4 to 166.3) | 0.28 ± 0.11 | 2 | 11.6 (−90.8 to 108.9) | 0.64 ± 1.52 | 97 | — | — | 0 |
| Thiamin4 | −27.9 (−31.2 to −24.7) | 0.28 ± 0.11 | 2 | −3.9 (−66.4 to 48.8) | 0.64 ± 1.52 | 97 | — | — | 0 |
| Vitamin B-124 | 65.1 | 0.06 | 1 | 8.4 (−49.4 to 64.3) | 0.63 ± 1.52 | 98 | — | — | 0 |
| Vitamin B-6 | 20.8 (−5.5 to 58.6) | 0.21 ± 0.15 | 3 | 2.6 (−67.4 to 22.8) | 0.64 ± 1.52 | 98 | 2 (−9.2 to 13.1) | 0.14 ± 0.08 | 2 |
| Vitamin C | 7.6 (−13.1 to 36.8) | 1.04 ± 2.18 | 43 | 8 (−96.7 to 25.5) | 0.37 ± 0.45 | 51 | 12.9 (11.1 to 13.8) | 0.09 ± 0.08 | 3 |
| Vitamin E | 2.9 (−7.7 to 8.6) | 0.15 ± 0.18 | 3 | 4.7 (−47.6 to 37.2) | 0.71 ± 1.6 | 87 | — | — | 0 |
Values are percentages (ranges) or means ± SDs. For every nutrient, we selected maximum RDA and UL values found for men (≥19 y) or women (nonpregnant, nonlactating) (14). RDA, Recommended Dietary Allowance; RMSE, relative market share estimate; UL, Tolerable Upper Intake Level.
Median n values differed between groups I and III and between groups II and III, but not between groups I and II (7, 62.5, and 0 for group I, II, and III, respectively; Kruskal-Wallis ANOVA on ranks, P < 0.001; pairwise comparison by Tukey test; P < 0.05).
The UL is determined only for magnesium intake from pharmacologic agents. This amount is below the RDA that was determined for magnesium intake from natural sources.
Nutrients for which ULs were not established.