Chemistry Reference
In-Depth Information
phylloquinone. Phylloquinone concentration in infant formulae milk ranges
from 3 to 16 mg/l in unsupplemented formulae and up to 100 mg/l in fortified
formulae.
The average intake of phylloquinone by infants fed human milk during
the first 6 months of life has been reported to be less than 1 mg/day, which is
approximately 100-fold lower than the intake by infants fed a typical supple-
mented formula (Greer et al., 1991). A study in Germany showed that a
minimum daily intake of about 100 ml of colostrum milk (which supplies
about 0.2-0.3 mg of phylloquinone) is sufficient for normal vitamin K home-
ostasis in a baby of about 3 kg during the first week of life (von Kries et al.,
1987). Similar conclusions were reached in a Japanese study which showed a
linear correlation between the prevalence of undercarboxylated coagulation
protein and the volume of breast milk ingested over 3 days (Motohara
et al., 1989).
12.5.7. Vitamin K Status and Requirements
12.5.7.1. Measurement of Vitamin K Status
Defining reliable indicators of vitamin K status has proven to be a
difficult task. The serum concentration of undercarboxylated osteocalcin
(ucOC, a protein secreted by osteoblasts in bone tissue) is a more sensi-
tive indicator of vitamin K status than the traditional blood coagulation
tests and a high serum level of ucOC is indicative of low vitamin K status
and vice versa (Vermeer et al., 1995; Sokoll et al., 1997). Undercarboxy-
lated osteocalcin has been reported to have a negative association with
plasma phylloquinone concentrations (Ferland et al., 1993). The difference
between the vitamin K-dependent coagulation factors (all synthesized in
the liver) and the bone Gla protein osteocalcin suggests that different
tissues (at least bone and liver) may have different vitamin K require-
ments: hence bone tissue may be more prone to vitamin K deficiency than
liver (Vermeer et al., 1995). If this is the case, impaired synthesis of some
vitamin K-dependent proteins may be far more prevalent in the human
population than coagulation assays previously indicated (Price, 1993),
potentially resulting in an increase in dietary recommendations for vitamin
K, especially for the elderly. A number of clinical trials have shown that
high circulating ucOC levels are common in post-menopausal women as
well as in healthy young and elderly adults but levels are reduced sig-
nificantly with vitamin K supplementation (Szulc et al., 1993; Binkley
et al., 2000). Even in healthy newborns, whose vitamin K status is
known to be precarious, very low levels of undercarboxylated prothrom-
bin are detectable, whereas all babies tested exhibited high concentrations
