Chemistry Reference
In-Depth Information
13.9.2.
Sources of Cobalamin
Cobalamin can be synthesized only by microorganisms and does
not occur in plant-derived food. Therefore, animal-derived foods con-
taining cobalamin are essential for humans; more or less good sources
are listed in Tables 13.11 and 13.12. In cow's milk, the cobalamin
content is very constant regarding feed, breed, season or stage of lacta-
tion, except colostrum which has a very high level. In contrast, concen-
trations in human milk are markedly lower than in cow's milk and vary
dependent on the above-mentioned parameters. Concentrations in the
milk of cow, human and other species and in some dairy products are
given in Table 13.12.
13.9.3.
Cobalamin Deficiencies
Although normally in developed countries the vitamin B12 uptake
meets the recommendations (Table 13.10), cobalamin deficiencies are the
most numerous ones in overall vitamin deficiencies to be clinically treated.
Table 13.10.
Recommended daily uptake of vitamin B12
Vitamin B12
mgMJ
-1
(nutrient density)
a
mg day
-1
Age
Male
Female
Sucklings
<
4 months
b
0.4
0.20
0.21
Sucklings 4-12 months
0.8
0.27
0.28
Children 1-4 years
1.0
0.21
0.23
Children 4-7 years
1.5
0.23
0.26
Children 7-10 years
1.8
0.22
0.25
Children 10-13 years
2.0
0.21
0.24
Children 13-15 years
3.0
0.27
0.32
Adults 15-25 years
3.0
0.28
0.36
Adults 25-51 years
3.0
0.29
0.38
Adults 51-65 years
3.0
0.33
0.41
Adults
>
65 years
3.0
0.36
0.43
Pregnant
c
3.5
0.38
Breast feeding
d
4.0
0.37
a
Calculated for adolescents and adults mostly sedentary (PAL value 1.4);
b
estimated value;
c
0.5 mg more for
filling up body stores and to maintain nutrient density;
d
approximately. 0.13 mg vitamin B12 added per 100 ml
secreted milk.
From DGE (2007)
