Lactoferrin is a major component of breast milk
protein, constituting 10-15% of the total content.
Each molecule of lactoferrin is capable of binding
two atoms of iron and it has been proposed that
lactoferrin is involved in iron absorption in the
newborn infant. It is known that iron status of exclusively
breast-fed infants usually is satisfactory
to 6-9 months of age, in spite of a low iron content
in breast milk.
Human milk contains significantly higher levels
of nucleotides (NT) and NT derivatives compared
with conventional infant formulas. NT can be synthesized
endogenously, and thus are not essential
The diamine putrescine and the polyamines spermidine
and spermine are ubiquitous substances
found virtually in all cells from higher prokaryotes
and eukaryotes [1-5].
Milks of various species contain a number of hormones
of a non-peptide and peptide character as
well as several hormonally active peptides. A list
of these active substances (to be called collectively
hormones) present in human milk is given in
table I; only selected references are listed here, the
reader being referred to preceding reviews for detailed
Mammalian milk and human milk in particular
contain many substances that can meet the nutritional
demands of the growing body, deliver micronutrients
which serve as mediators for growth
and differentiation of tissues and organs, and multiple
The composition of mammalian milk is unique to each species and adapted to the demands of the growing
offspring. It provides specific nutritional support to meet the rapid growth of the newborn. Despite
the great variability among mammalian milks, each serves the same purpose: safeguarding growth and
development until the offspring is able to acquire its own food and survive without its mother.