Recommendations for protein intake in normal infants (1,2) are based on
the assumption that human milk has a nutritionally available protein content
of 12 to 13 g/liter (3). Based on amino acid analysis of milk protein, the
protein content is 8.8 g/liter (4), and based on nondialyzable nitrogen, 9.6
The nutrient intake of exclusively breast-fed infants has been used as a
guide for the dietary requirements of healthy infants.
The membranes of milk fat globules are derived from apical plasma membrane
of the lactating mammary epithelial cells.
Human milk, like the milk of other species, contains numerous enzymes.
Although this topic has been reviewed (1-4), the first two publications provide
little information about the physiological significance of these enzymes.
Shahani et al.
Human milk is considered an optimal source of calcium and phosphorus
for the feeding of normal term infants because of its satisfactory calcium/
phosphorus ratio and low phosphorus concentration, and because it is an
adequate source of antirachitic activity (1).
Under natural conditions, milk is the only food of the newborn mammal;
it must therefore provide all the nutrients necessary for normal growth and
development of the infant.
Taurine (2-aminoethanesulfonate) is a sulfur-containing (3-amino acid
present in many animal species but rare in most species of plants (1).
Over the years, many hormones have been identified in the milk of humans
and other mammals (1).
The presence of hormones in milk was described 50 years ago (1-3), and
important studies were performed in the late 1950s (4,5); but only in the past
decade have methodological advances in hormone assays allowed detailed
exploration of this subject.
Almost a 100 years ago, Ehrlich demonstrated that milk contains protective
factors (1). They were later found in the milk from various species,
Human milk is known to contain numerous components with potential
antimicrobial effects—immunoglobulins, enzymes, nutrient binding proteins,
components of the complement system, receptor analogs, etc.
Human and other mammalian colostrum and milk contain a variety of
Human milk contains mucosal antibodies, a special class of polymeric
immunoglobulins associated with secretory component (SC) (Fig. 1), which
play a crucial role in protecting the newborn against environmental pathogens.
Animal experiments, especially those of the late Ellen Jarrett on hooded
Lister rats, indicate that massive allergen contact is needed to induce tolerance
The intestinal tract and microbial flora of mammals and birds constitute
a very complex ecosystem that plays a major role in the health of the host.
We like to think that we do research; I think we must realize that we
actually do re-search most of the time.
function of, 51,57
as metal carrier, 51,57
in animals, 197-198
food intake and, 197-198
in humans, 197,198-201,202-203
IgE production and, 197
IgG antibodies and, 200
maternal diet and, 197-201