Chemistry Reference
In-Depth Information
bovine colostrum is 100-160 mg/l but declines by over 50% during the first 3 d
of lactation (de Maria, 1978). Oral supplementation of large doses of man-
ganese for an extended time can increase the manganese content of milk from
bovine milk (Archibald, 1958).
In human milk, 67% of manganese is bound to lactoferrin, 11% to
casein, 18% to the fat globule membrane, and 4% in a low-molecular-weight
form (Lonnerdal et al., 1985). In bovine milk, 67% of manganese is bound to
casein, 1% in the fat globule membrane, 14% to whey proteins and 18% in a
low-molecular-weight form (Lonnerdal et al., 1985). Very little is known
about the availability of manganese in milk to infants. Manganese absorption
by human adults was higher (8.4%) from human milk than from bovine milk
(2.4%) or bovine milk-based infant formula (3.1%) (Davidsson et al., 1989).
However, suckling rats absorbed about the same percentage (between 80 and
89%) of manganese from human milk, bovine milk and bovine milk-based
formula (Keen et al., 1986); this finding suggests that infants absorb a greater
percentage of manganese from milk than adults do.
Based on the fact that infants do not have fully developed homeostatic
control of manganese, its content in formulae has raised concerns. In the early
1980s, supplementation of formulae resulted in some having 100-1000 times
higher amounts of manganese than in human milk (Lonnerdal et al., 1983;
Stastny et al., 1984). Even without manganese supplementation, milk-based
infant formulae contain more manganese than human milk (2-4 mg/l) because
of the higher concentration of this element in bovine milk (30 mg/l). Manganese
supplementation of formulae has now ceased, so they now contain manganese
in the range of 34-300 mg/l (Lonnerdal, 1985; Johnson et al., 1998), which is
lower than the recommended UL of 335-600 mg/l in infant formula (Lonnerdal,
1985; Hambidge and Krebs, 1989). The FNB did not set a manganese UL for
infants, but set 2 mg/d as an UL for children aged 1-3 yr (Food and Nutrition
Board: Institute of Medicine, 2001).
For adults, milk and milk products are considered poor sources of
manganese. Bovine milk has been estimated to contribute 1-3% of the dietary
intake of manganese in Western countries (Hazell, 1985).
10.10.
Selenium
Selenium is involved in many biological functions, including thyroid, neural
and immune function and protection against oxidative stress and gastroin-
testinal disease (Food and Nutrition Board: Institute of Medicine, 2000; Burk
and Hill, 2005; Esworthy et al., 2005; Sunde, 2006). Research with Coxsackie-
virus indicates that oxidative stress in a selenium-deficient host leads to
genomic changes of an RNA virus that can increase virulence (Beck et al.,
