Chemistry Reference
In-Depth Information
TABLE 5
Fractional Zn Absorption From Total Diets, Measured by Isotopic Techniques (Commitee, 2001)
Zn content
µ
mol
Phytate/Zn
Zn absorption,
Subjects
Isotopes
Diets
(mg)
molar ratio
% (× ± SD)
Young adults (Petterson,
Radioactive
High fi ber
163 (10.7)
7
27 ± 6
Sandstrome and
Cederblad, 1994)
Young women
Stable isotope
Habitual
124 (8.1)
10
34 ± 9
(Knudsen
et al
., 1995)
Women (20-42 y)
Radioisotope
Lacto-ovo-
139 (9.1)
14
26 ± 5
(Hunt, Matthys and
vegetarian
169 (11.1)
5
33
Johnson, 1998)
omnivorous
Women (20-42y) (Hunt, Matthys
vegetarian
169 (11.1)
5
33
and Johnson, 1998)
Radioisotope
“Low meat”
102 (6.7)
30 ± 4.6
Postmenopausal
Radioisotope
“High meat”
198 (13.0)
28 ± 4.6
women (Hunt
et al
., 1995)
content were both increased (
P
= 0.001) (Sandstead
et al
., 1984; Sandstead
et al
., 1990).
Evaluation of the data by regression analysis iden-
tifi ed signifi cant predictors of Zn intake, which is
equivalent to the requirement when balance is in equi-
librium. The equation that describes these relationships
is: Zn intake = −2.02 + 18.21(diet phytate)−3.52(diet
phosphorus) + 0.26(diet nitrogen) + 0.31(Zn balance)
+ 2.84(diet Ca) + 2.81(diet Cu)−9.32(diet Mg) (number
of observations = 183,
R
2
= 0.905,
P
< 0.0001) (Sandstead
and Smith, 1996; Sandstead, 1986). This model is con-
sistent with factors that are known to affect Zn bio-
availability.
A simplifi ed regression model that included the
nitrogen (N) and phosphorus (P) intakes was used to
calculate the requirement and compare it with intakes
TABLE 6
Dietary Reference Values for Zinc (mg/d)
European DRI
United Kingdom
USA RDA
a
(Commission
(Department of
(Committee on
WHO DRI
of the European
Health, 1991)
Micronutrients, 2001)
(Committee, 1996)
Communities, 1993)
LNRI
EAR
RNI
Infants
0-3 months
2.6
3.3
4.0
2.0
4-6 months
2.6
3.3
4.0
3.0
7-12 months
3.0
3.8
5.0
3.0
5.6
4.0
1-3 y
3.0
3.8
5.0
3.0
5.5
4.0
4-6 y
4.0
5.0
6.5
5.0
6.5
6.0
7-10 y
4.0
5.4
7.0
8.0
7.5
7.0
Males
11-14 y
5.3
7.0
9.0
8.0
12.1
9.0
15-18 y
5.5
7.3
9.5
11.0
13.1
9.5
19-50+ y
5.5
7.3
9.5
11.0
9.4
9.5
Females
11-14 y
5.3
7.0
9.0
8.0
10.3
9.0
15-18 y
4.0
5.5
7.0
9.0
10.2
7.0
19-50+ y
4.0
5.5
7.0
8.0
6.5
7.1
Pregnancy
11.0
7.3-13.3
Lactation
0-4 months
12.0
12.7
+5.0
4+ months
12
11.7
+5.0
a
Age
groups of the RDA do not coincide exactly with the age groups of the other standards.
DRI, Dietary reference intake; EAR, estimated average requirement; LNRI, lower reference nutrient intake; RDA, recommended daily
allowance; RNI, recommended nutrient intake.
