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ORIGINAL ARTICLE
Whole cow’s milk in infancy
Alexander KC Leung MBBS FRCPC FRCP (UK and Ireland) FRCPCH, Reginald S Sauve MD FRCPC
AKC Leung, RS Sauve. Whole cow’s milk in infancy. Paediatr
Child Health 2003;8(7):419-421.
Early introduction of whole cow’s milk may lead to iron deficiency anemia. From a nutritional point of view, it is best to delay the introduction of whole cow’s milk until the infant is one year old. While there is
no evidence to suggest adverse clinical sequelae associated with the
increased renal solute load in healthy infants, feeding with whole cow’s
milk would narrow the margin of safety in situations that may lead to
dehydration. Early exposure to cow’s milk proteins increases the risk of
developing allergy to milk proteins. Because of the possible association
between early exposure to cow’s milk proteins and risk for type 1 diabetes mellitus, breast-feeding and avoidance of commercially available
cow’s milk and products containing intact cow’s milk protein during
the first year of life are strongly encouraged in families with a strong history of insulin dependent diabetes mellitus. The authors suggest that
the optimal food in infancy is human breast milk. If human milk is not
available, it is preferred that iron-fortified formulas rather than whole
cow’s milk be used during the first year of life.
Key words: whole cow’s milk; infancy
n recent years, there has been a decline in the use of whole
Icow’s milk in infant feeding (1). Nevertheless, many parents
still make the transition from breast feeding or formula to
whole cow’s milk when the infant is less than one year of age.
In the United States (2) and the United Kingdom (3), it is recommended that whole cow’s milk should not be used before
one year of age. In Denmark (4), it is recommended that
whole cow’s milk can be introduced gradually from nine
months of age and in Sweden (5) from 10 months of age. The
Nutrition Committee of the Canadian Paediatric Society recommends that whole cow’s milk may be introduced at nine
to 12 months of age (6). There are potential hazards associated with early introduction of whole cow’s milk.
IRON DEFICIENCY ANEMIA
The use of whole cow’s milk can be associated with occult
loss of blood from the gastrointestinal tract, in both early and
late infancy. Ziegler et al (7) randomly assigned 52 infants to
receive either whole cow’s milk or a milk-based formula at
168 days of age. With the feeding of whole cow’s milk, the
proportion of guaiac-positive stools increased from 3% at
baseline to 30.3% during the first 28 days of the trial
(P<0.01), whereas the proportion of guaiac-positive stools
Le lait de vache entier pendant la première
enfance
L’adoption précoce de lait de vache entier chez les nourrissons peut
entraîner une anémie ferriprive. D’un point de vue nutritionnel, il est
préférable de retarder l’adoption du lait de vache entier jusqu’à ce que
l’enfant ait un an. Bien qu’aucune donnée ne laisse supposer la possibilité
de séquelles cliniques néfastes causées par la charge osmotique accrue des
substances filtrées chez les nourrissons en santé, l’alimentation à l’aide de
lait entier de vache réduit la marge de sécurité dans des cas qui peuvent
provoquer une déshydratation. Une exposition précoce aux protéines du
lait de vache accroît le risque que l’enfant développe une allergie aux
protéines du lait. Étant donné l’association possible entre une exposition
précoce aux protéines du lait de vache et le risque de diabète de type I,
l’allaitement et l’évitement du lait de vache offert sur le marché et des
produits contenant des protéines intactes de lait de vache au cours de la
première année de vie sont fortement préconisés au sein des familles
présentant des antécédents marqués de diabète de type I. Les auteurs
indiquent que l’aliment optimal pendant la première enfance demeure le
lait maternel. Si celui-ci n’est pas disponible, il est préférable de choisir un
lait maternisé contenant des suppléments de fer plutôt que du lait de vache
entier pendant la première année de vie.
remained low (5%) with the feeding of formula. Although the
proportion of guaiac-positive stools among infants fed whole
cow’s milk declined later, it remained significantly elevated
(P<0.01) for the entire trial. Stool hemoglobin concentration
increased markedly with the introduction of whole cow’s
milk from a mean (± SD) of 622±527 µg/g dry stool at baseline to 3598±10,479 µg/g dry stool during the first 28 days of
ingestion of whole cow’s milk. Among infants fed formula,
stool hemoglobin did not increase and was significantly
(P<0.01) less than that in the group fed whole cow’s milk.
Although normal infants lose measurable amounts of blood
in the feces at all times, feeding with whole cow’s milk leads
to increased enteric blood loss in a large proportion of normal infants (7,8). Because feeding with a heat processed cow’s
milk proprietary formula would not result in increased
enteric blood loss, it has been suggested that a heat labile protein such as bovine albumin in whole cow’s milk is responsible for intestinal bleeding (8). Cow’s milk-induced blood loss
tends to occur only during infancy; even exquisitely sensitive
infants tend to tolerate whole cow’s milk later in life without
adverse effects (8).
The levels of iron in both breast milk and whole cow’s
milk are low, less than 0.3mg/L to 1 mg/L (9). Iron in breast
Deparment of Paediatrics, University of Calgary and the Alberta Children’s Hospital, Calgary, Alberta
Correspondence: Dr Alexander KC Leung, #200, 233-16th Avenue NW, Calgary, Alberta T2M 0H5. Telephone 403-230-3300,
fax 403-230-3322, e-mail [email protected]
Paediatr Child Health Vol 8 No 7 September 2003
©2003 Pulsus Group Inc. All rights reserved
419
Leung et al
milk is highly bioavailable, possibly because of the lower calcium and phosphorus content and the presence of lactoferrin
(9). On the other hand, bovine milk proteins are potent
inhibitors of iron absorption. Approximately 50% of the iron
in the breast milk is absorbed compared with approximately
10% of that in whole cow’s milk (10).
Several studies showed that feeding infants with whole
cow’s milk instead of iron-fortified formula at six months of
age resulted in an increased incidence of iron deficiency by
one year of age (11,12). Supplemental foods may not always
supply the necessary amounts of iron in the second six
months of life (2,11). Iron deficiency anemia, especially during the first two years of life, can adversely affect behaviour
and psychomotor development (13).
NUTRITIONAL CONSIDERATIONS
Protein provides approximately 7% of the calories in human
milk and 20% of the calories in whole cow’s milk (14).
Although the amounts of whey protein are similar, whole
cow’s milk contains six to seven times as much casein as does
human milk (14). The whey to casein ratio of human milk is
approximately 35:65 whereas the whey to casein ratio of
whole cow’s milk is 19:81 (14). The high casein content of
whole cow’s milk is undesirable because casein forms a tough,
hard to digest curd that is difficult for young infants to digest
(15). The amino acids taurine and cystine are present in
much higher concentrations in human milk than in whole
cow’s milk (13). These amino acids may be essential for premature infants.
Lipids provide 50% of the calories in both human and
whole cow’s milk. Human milk contains a greater concentration of linoleic acid and polyunsaturated fatty acids than
whole cow’s milk. Linoleic acid provides 4% of calories in
human milk but only 1.8% in whole cow’s milk, the recommended level being 3% (2). The fatty acid profile in infant
formulas simulates that of human milk. As such, fats in
infant formulas are absorbed quite well by most infants and
better than those in whole cow’s milk (14).
Whole cow’s milk also has low contents of zinc, niacin,
vitamin C and vitamin E (6). Whole cow’s milk contains
approximately three times as much sodium and potassium,
four times as much calcium and six times as much phosphorus
as does human milk (14). The high phosphate load has been
implicated as a cause of late hypocalcemic tetany of the
neonate (14). For all the above reasons, it is best to delay the
introduction of whole cow’s milk until the infant is one year
old.
HIGH RENAL SOLUTE LOAD
A higher intake of protein, sodium, potassium, chloride and
phosphorus associated with the use of whole cow’s milk
inappropriately increases the renal solute load (6,16). The
higher renal solute load of whole cow’s milk results in a urinary osmolality approximately twice that observed in breast
fed infants (17). While there is no evidence to suggest adverse
clinical sequelae associated with the increased renal solute
load in healthy infants, feeding with whole cow’s milk would
420
narrow the margin of safety in situations that may lead to
dehydration (16). Under circumstances in which water intake
is reduced (eg, vomiting) or water loss is increased (eg, diarrhea, hot environment), whole cow’s milk may not supply
enough free water. Dehydration may result unless additional
water is offered.
COW’S MILK ALLERGY
Cow’s milk allergy affects 0.3% to 7.5% of infants (18). There
is no evidence to suggest that whole cow’s milk is more allergenic than infant formulas that contain intact cow’s milk proteins. Infants with cow’s milk protein allergy should not be
fed either whole cow’s milk or formulas containing intact
whole cow’s milk proteins (2).
Early exposure to cow’s milk proteins increases the risk of
developing allergy to milk proteins. With increasing maturation, the intestinal epithelium becomes less permeable to
macromolecules and there is less tendency toward allergic
reactions. In normal infants without a known history of allergy to cow’s milk, the introduction of whole cow’s milk should
be based on nutritional considerations, and not on the development of mucosal barrier to cow’s milk proteins (2).
Several studies have reported the detection of cow’s milk
antigen in human milk (19,20). Exposure to even minute
amounts of cow’s milk protein in human milk may elicit allergic reactions (21). Several investigators found that the incidence of atopic dermatitis was significantly lower in the
group of children whose lactating mothers had a diet free
from cow’s milk whereas the incidences of all other atopic
manifestations were similar compared with a control group of
children whose mothers had no dietary restrictions (22,23).
Other investigators found no preventive effect on the development of atopic diseases in children whose mothers avoided
cow’s milk in the diet (24). It is premature, at the present
stage, to advocate avoidance of whole cow’s milk during lactation to families with atopy. Further studies are necessary
before a definitive recommendation can be made.
Nevertheless, if the lactating mother notices that consumption of whole cow’s milk seems to cause an allergic reaction
in her infant, it is reasonable to eliminate whole cow’s milk
from her diet.
DIABETES MELLITUS
An association between early exposure to cow’s milk proteins
and risk for type 1 diabetes mellitus has been reported in
many (25-28) but not all (29) studies. Exposure to cow’s milk
proteins elicits antibody formation to insulin in some children (25,26,28). Bovine serum albumin may provoke an
immunological response in genetically susceptible individuals, which then cross reacts with a beta-cell surface protein, p
69 (25,26). The expression of this protein on the surface of
beta cells is believed to mediate their destruction by exposing
them to immune attack (26). Destruction of beta cells may
lead to the development of diabetes mellitus. The American
Academy of Pediatrics recommends that in families with a
strong history of insulin-dependent diabetes mellitus, breastfeeding and avoidance of commercially available cow’s milk
Paediatr Child Health Vol 8 No 7 September 2003
Whole cow’s milk in infancy
and products containing intact cow’s milk proteins during
the first year of life are strongly encouraged (30). Because the
antigenicity of infant formulas and whole cow’s milk may be
different and there is no evidence against the use of formulas
for infants whose mothers do not breast-feed, commercial
infant formulas using cow’s milk protein are an acceptable
alternative (30). These recommendations should be followed
until prospective well-designed randomized trials determine
the relationship between cow’s milk proteins and diabetes
mellitus.
CONCLUSION
The optimal food in infancy is human breast milk. If human
milk is not available, it is preferred that iron-fortified formulas, rather than whole cow’s milk, be used during the first
year of life.
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