F
Rationale for Setting Adequate Intakes
In the Dietary Reference Intake (DRI) nutrient reports, the Adequate Intake (AI) has been estimated in a number of different ways. Because of this, the exact meanings and interpretations of the AIs differ. Some AIs have been based on the observed mean intake of groups or subpopulations that are maintaining health and nutritional status consistent with meeting the criteria for adequacy. However, where reliable information about these intakes was not available, or where there were conflicting data, other approaches were used. As a result, the definition of an AI is broad and includes experimentally estimated desirable intakes.
These varying methods of setting an AI make using the AI for assessing intakes of groups difficult. When the AI is based directly on intakes of apparently healthy populations, it is correct to assume that other populations (with similar distributions of intakes) have a low prevalence of inadequate intakes if the mean intake is at or above the AI. For nutrients for which the AI was not based on intakes of apparently healthy populations, a group mean intake at or above the AI would still indicate a low prevalence of inadequate intakes for that group but there is less confidence in this assessment. Table F-1, Table F-2, Table F-3, Table F-4, Table F-5 through Table F-6 give more details on the methods used to set the AIs for calcium, vitamin D, fluoride, pantothenic acid, biotin, and choline. For infants, AIs have been set for all nutrients evaluated to date (see table at the end of this book). For all these nutrients except vitamin D, the AI for infants is based on intakes of healthy populations that are fed only human milk. How-
ever, for the other age groups, only fluoride and pantothenic acid AIs are based on intakes of apparently healthy populations.
TABLE F-1 Adequate Intake (AI) for Calcium
Life Stage Group |
AI (mg/d) |
Basis for AI |
0–6 mo |
210 |
Human milk content |
7–12 mo |
270 |
Human milk content + solid food |
1–3 y |
500 |
Extrapolation from AI for 4–8 y (desirable calcium retention) |
4–8 y |
800 |
Calcium balance, calcium accretion, ∆BMCb |
9–18 y |
1,300 |
Desirable calcium retention, ∆BMC, factorial |
19–30 y |
1,000 |
Desirable calcium retention, factorial |
31–50 y |
1,000 |
Calcium balance, BMDc |
Study Populationa |
Balance studies: n=60 girls and 39 boys; aged 2–8 y; normal and healthy (Matkovic, 1991; Matkovic and Heaney, 1992) |
Retention studies:
|
BMC studies:
|
n=26 men and 137 women; aged 18–30 y; normal and healthy (Matkovic and Heaney, 1992) |
Balance studies:
|
BMD studies:
|
TABLE F-1 Adequate Intake (AI) for Calcium
Study Population |
Retention studies:
|
BMD studies:
|
TABLE F-2 Adequate Intake (AI) for Vitamin D
Life Stage Group |
AI (μg/d) |
Basis for AI |
0–6 mo |
5 |
Serum 25(OH)Db level |
7–12 mo |
5 |
Serum 25(OH)D level |
1–3 y 4–8 y 9–13 y 14–18 y |
5 |
Serum 25(OH)D level |
19–50 y |
5 |
Serum 25(OH)D level |
51–70 y |
10 |
Serum 25(OH)D level |
>70 y |
15 |
Serum 25(OH)D level |
Pregnancy and lactation, all ages |
5 |
Serum 25(OH)D level |
a Unless noted otherwise, all studies were performed in the United States or Canada. b 25 (OH)D = 25-hydroxyvitamin D. |
Study Populationa |
n= 256 full-term Chinese infants (Specker et al., 1992) |
|
|
|
|
|
TABLE F-3 Adequate Intake (AI) for Fluoride
Life Stage Group |
AI (mg/d)a |
Basis for AI |
0–6 mo |
0.01 |
Human milk content |
7–12 mo |
0.5 |
Caries prevention |
1–3 y |
0.7 |
Caries prevention |
4–8 y |
1 |
Caries prevention |
9–13 y |
2 |
Caries prevention |
14–18 y, males |
3 |
Caries prevention |
14–18 y, females |
3 |
Caries prevention |
>19 y, males |
4 |
Caries prevention |
>19 y, females |
3 |
Caries prevention |
Pregnancy and lactation, <18 y |
3 |
Caries prevention |
Pregnancy and lactation, 19–50 y |
3 |
Caries prevention |
a For all life stage groups, the AI was calculated using 0.05 mg/kg/day as the amount of fluoride needed to prevent dental caries. This amount was based on the studies outlined in this table. b Unless noted otherwise, all studies were performed in the United States or Canada. |
Study Populationb |
Caries prevention was based on the following studies that measured or calculated fluoride intake in children:
|
Caries prevention was based on the following studies which measured or calculated fluoride intake in adults:
|
TABLE F-4 Adequate Intake (AI) for Pantothenic Acid
Life Stage Group |
AI (mg/d) |
Basis for AI |
0–6 mo |
1.7 |
Human milk content |
7–12 mo |
1.8 |
Mean of extrapolation from AI for 0–6 mo and adult AIb |
1–3 y |
2 |
Extrapolation from adult AI |
4–8 y |
3 |
Extrapolation from adult AI |
9–13 y |
4 |
Extrapolation from adult AI |
14–18 y |
5 |
Extrapolation from adult AI, urinary pantothenate excretion |
≥ 19 y |
5 |
Usual intake |
Pregnancy, all ages |
6 |
Usual intake |
Lactation, all ages |
7 |
Usual intake, maternal blood concentrations, secretion of pantothenic acid into milk |
a Unless noted otherwise, all studies were performed in the United States or Canada. b To extrapolate from the AI for adults to an AI for children, the following formula is used AIchild = AIadult (F), where F = (Weightchild/Weightadult)0.75 (1 + growth factor). To extrapolate from the AI for infants ages 0–6 months to an AI for infants ages 7–12 months, the following formula is used: AI7–12mo= AI0–6mo (F), where F = (Weight7–12mo/ Weight0–6mo)0.75. |
Study Populationa |
|
Usual intake was based on 4 studies:
|
TABLE F-5 Adequate Intake (AI) for Biotin
Life Stage Group |
AI (μg/d) |
Basis for AI |
0–6 mo |
5 |
Human milk content |
7–12 mo |
6 |
Extrapolation from AI for 0–6 moa |
1–3 y |
8 |
Extrapolation from AI for 0–6 mob |
4–8 y |
12 |
Extrapolation from AI for 0–6 mob |
9–13 y |
20 |
Extrapolation from AI for 0–6 mob |
14–18 y |
25 |
Extrapolation from AI for 0–6 mob |
Adults, all ages |
30 |
Extrapolation from AI for 0–6 moc |
Pregnancy, all ages |
30 |
Extrapolation from AI for 0–6 mo |
Lactation, all ages |
35 |
Extrapolation from AI for 0–6 mo + amount of biotin secreted into milk |
a To extrapolate from the AI for infants ages 0–6 months to an AI for infants ages 7–12 months, the following formula is used: AI7–12mo = AI0–6mo (F), where F = (Weight7–12mo/ Weight0–6mo)0.75. b To extrapolate from the AI for infants ages 0-6 months to an AI for children and adolescents 1-18 years, the following formula is used: AIchild = AI0-6mo (F), where F = (Weightchild/Weight0-6mo)0.75. c To extrapolate from the AI for infants ages 0-6 months to an AI for adults, the following formula is used: AIadult = AI0-6mo (F), where F = (Weightadult/Weight0-6mo)0.75. |
TABLE F-6 Adequate Intake (AI) for Choline
Life Stage Group |
AI (mg/d) |
Basis for AI |
0–6 mo |
125 |
Human milk content |
7–12 mo |
150 |
Extrapolation from AI for 0–6 moa |
1–3 y |
200 |
Extrapolation from adult AI |
4–8 y |
250 |
Extrapolation from adult AI |
9–13 y |
375 |
Extrapolation from adult AI |
14–18 y, males |
550 |
Extrapolation from adult AI |
14–18 y, females |
400 |
Extrapolation from adult AI |
≥19 y, males |
550 |
Prevention of ALTb abnormalities |
≥19 y, females |
425 |
Prevention of ALT abnormalities |
Pregnancy, all ages |
450 |
Prevention of ALT abnormalities + cost of pregnancy |
Lactation, all ages |
550 |
Prevention of ALT abnormalities + amount of choline secreted into milk |
a To extrapolate from the AI for adults to an AI for children, the following formula is used AIchild= AIadult (F), where F = (Weightchild/Weightadult)0.75 (1 + growth factor). To extrapolate from the AI for infants ages 0–6 months to an AI for infants ages 7–12 months, the following formula is used: AI7–12mo = AI0–6mo (F), where F = (Weight7–12mo/ Weight0–6mo)0.75. b ALT = alanine aminotransferase. |