Breastfeeding,
why...
Obesity
Toschke AM, et al. Overweight
and obesity in 6- to 14-year-old Czech children in
1991: protective effect of breastfeeding. J Pediatr 2002;141:764-9
In 1991, more than 33,000 Czech children aged 6-14
years were studied in a cross sectional survey
to assess the
impact of breastfeeding on childhood overweight and
obesity; 9.3% of them were never breastfed. Among
these, 12.4%
were overweight and 4.4% obese, compared to 9.3% and
3.2% among the 30,641 ever breastfed. Longer duration
of breastfeeding was associated with a significantly
lower prevalence of overweight, but no effect was seen
for obesity. The fact that the baby’s intake varies
at each feed during breastfeeding, a lower energy density
of human milk compared with formula milk, and thus a
better self-control of food consumption in breastfed
children, are possible explanations for the observed
effect of breastfeeding.
Parsons TJ, Power C, Manor O. Infant
feeding and obesity through the lifecourse. Arch Dis Child
2003;88:793-4
In another study all children born in England, Wales
and Scotland in 1958 were studied, with the result
that, differently from the above article on Czech
children, no relationship was found between breastfeeding
and
BMI.
Data were obtained for 98% of 17,733 births. BMI
was calculated from heights and weights, at 7,
11, 16 and
33 years. Breastfeeding was protective against
increased BMI in females at ages 16 and 33 years,
and in males
at 33 years, but this effect was reduced and no
longer significant after adjustment for confounding
factors.
Li L, Parsons TJ, Power C. Breastfeeding
and obesity in childhood: cross-sectional study. BMJ 2003:327:904-5
In a British study of 2,631 children - offspring
born from the 1958 cohort described above -
no protective effect of breastfeeding on obesity
was found. Adjustments
for confounding factors - birth weight, mother's
smoking
during pregnancy - did not alter these findings.
Victora CG et al. Anthropometry
and body composition of 18-year-old men according
to duration
of breastfeeding: a birth cohort study from Brazil. BMJ 2003;327:901-4
2,250
18-year-old men of a relatively affluent Brazilian
city were studied to look at the effect
of breastfeeding
on several measures of adiposity, including
BMI. They had been enrolled at birth in a large cohort
study. Neither
the duration of total breastfeeding nor
that of predominant breastfeeding showed significant
association with BMI.
However, a significant reduction in obesity
was found among those breastfed between 3 to 5 months,
which is
difficult to explain. The authors speculate
about whether truly exclusive breastfeeding would have
resulted in
a clearer pattern of association with obesity.
Frye
C, Heinrich J. Trends and predictors of overweight
and obesity
in East German children. Int J Obes Relat
Metab Disord 2003;27:963-9
In three consecutive surveys performed
in Eastern Germany (1992-3; 1995-6
and 1998-9)
with 5-
to 14-year-old school children, more
than 7,000 were assessed in
order
to analyze
the trends in overweight and obesity,
according to selected factors. A significant increase
was
shown
for 11-14 y
and for 8-10 y, but not for the school
entrants aged 5-7 y. Low-birth weight
and
higher parental
education
were protective factors against overweight
and obesity, while breastfeeding was
protective only
with regard
to obesity. This effect was stronger
if the children were
exclusively breastfed.
Grummer-Strawn LM, Mei Z. Does
breastfeeding protect against pediatric overweight?
Analysis of longitudinal
data from the Centers for Diseases
Control and Prevention Pediatric
Nutrition Surveillance
System. Pediatrics
2004;13:e81-6
Among a huge sample of children (177,304
up to 60 months of age), the authors
of this study
examined whether
increased duration of breastfeeding
is associated with a lower
risk of obesity in a low-income
American population. A statistical analysis
was performed controlling
for gender, ethnicity, and birth
weight. For 12,587 children,
data from pregnancy were available
also. The longer the duration of
breastfeeding beyond
6
months,
the
higher
the protective effect and the lower
the
risk of overweight among non-Hispanic
whites, but not among
Blacks or
Hispanics. Breastfeeding for any
duration was also protective against
underweight.
Butte NF.
The role of breastfeeding
in obesity. Pediatr Clin North
Amer 2001;48:189-98
In a review of 18 studies, this
author concludes that the protective
effect
of breastfeeding
on later obesity
remains controversial. 12 studies
found a non significant effect,
while only
4 showed
a protective
effect.
Parental obesity continues
to be the strongest determinant for
childhood obesity; this may
be partly due to genetic factors
(studies on
twins and
adopted
children
had already provided estimates
of genetic contribution) and
partly to shared dietary habits. This
review
confirms that
childhood obesity is caused
by several factors; disentangling
the
effect of breastfeeding is
difficult and requires control of many
confounding variables
on which
information is not always available
or complete.
Dewey
KG. Is breastfeeding protective against child
obesity? J Human Lact 2003;19:9-18
The author reviews the different
studies published up to
2003 that investigate
childhood obesity
and breastfeeding. She
concludes that to understand the relationship,
it
is necessary to know how
to control as many confounding
variables
as possible;
but calls
attention on
the
difficulty to control:
1)
child-feeding
practices and parental
control over feeding, and
2) physical activity. Breastfeeding
might reduce
child overweight
by metabolic programming
in early life, but this has
to
be studied in more depth.
High
blood pressure
Owen CG, Whincup PH, Gilg JA, Cook DG. Effect
of breast feeding in infancy on blood pressure in
later life: systematic
review and meta-analysis. BMJ 2003;327:1189-95
The association between infant feeding and blood
pressure in later life is controversial. A systematic
review of
25 studies concludes that the selective publication
of small studies with positive findings may have
exaggerated
claims that breastfeeding in infancy reduces blood
pressure in later life. The results of larger
studies suggest
that feeding in infancy has, at most, a modest effect
on systolic blood pressure, of limited clinical or
public health importance, and no effect on diastolic
blood pressure.
Singhal
A, Cole TJ, Lucas A. Early nutrition in pre-term
infants and later blood pressure: two cohorts after
randomised trials. Lancet 2001;357:413-9
Consumption of human milk has been shown to have
many benefits for infants - both pre-term and full
term
- including a reduced risk of necrotizing enterocolitis,
atopy, infections and improved later cognitive
development. The hypothesis that consumption
of human milk also
may
lower blood pressure is supported by this randomised
trial and by two other studies. Both mean and diastolic
blood pressures were lower comparing infants fed
donated human milk with those fed pre-term formula.
Even among
those babies whose mothers decided to provide breastmilk
in addition to the assigned formula diet, diastolic,
systolic and mean blood pressure were lower. Further
investigation may elucidate mechanisms for early
life nutritional programming leading to low or
high blood
pressure.
Martin RM,
Ness AR, Gunnell D, Emmett P, Smith GD. Does
breastfeeding in infancy lower
blood
pressure
in childhood? The Avon Longitudinal study of
parents and children (ALSPAC). Circulation 2004;109:1259-66
Breastfeeding was associated with lower systolic
blood pressure at 7 years in a study done with
more than
7,000 UK children. Of all mothers, 83% reported
having ever
breastfed and 34% reported exclusive breastfeeding
beyond 2 months (although some water might
be included in this
definition, it was restrictive for all other
liquids besides breastmilk). Of those who breastfed,
49%
did so for 6 months. The systolic and diastolic
blood pressures
of breastfed children were 1.2 mm Hg lower
and 0.9 mm Hg lower, respectively, compared with
children who were
never breastfed, after controlling for age,
sex,
room temperature and field observer. Overall,
there was
a 0.2 mm Hg reduction in systolic blood pressure
for each
3 months of any breastfeeding. The importance
of this study is that it took place during
the 1990s,
when
infant formula contained less salt than formula
manufactured
earlier. Even so, children fed infant formula
compared to those breastfed presented higher
blood pressure.
One
explanation is the higher sodium content of
infant formula. The authors also discuss the
implications
of this small
reduction: lower systolic pressure in 1% of
the population is associated with approximately
1.5%
reduction in
all-cause mortality.
Cholesterol
Owen CG, Whincup PH, Odoki K, Gilg JA, Cook DG. Infant
feeding and blood cholesterol: a study in adolescents
and a systematic review. Pediatrics 2002;110:597-608
The authors examined the influence of infant feeding
methods on total serum cholesterol (TC) and low-density
lipoprotein (LDL) cholesterol, both associated with
high incidence of coronary heart disease and
arteriosclerosis.
They conducted a cross-sectional study of 13-to 16-year-olds
and reviewed a number of observational studies on the
effects of infant feeding on cholesterol in infancy
(<1
year), childhood/adolescence (1-16 years), and adulthood
(17 years or over). 1,532 individuals (92% white; 55%
male; mean age: 15.1 years) in ten British towns were
examined; and 37 studies with 52 observations on TC/LDL
(26/7 in infancy, 17/4 in childhood or adolescence, and
9/6 in adulthood) were reviewed. The results show that
breastfeeding is associated with increased mean TC and
LDL levels in infancy, but lower levels in adulthood.
These results suggest that breastfeeding may have long-term
benefits for cardiovascular health.
Singhal A, Cole TJ, Fewtrell M, Lucas A. Breastmilk
feeding and lipoprotein profile in adolescents born
pre-term:
follow-up of a prospective randomised study. Lancet
2004;363:1571-8
Breastfeeding is associated with reduced cholesterol
concentration later in life, but previous studies
have not used random assignment of infant diet
with prospective
follow-up. This study did so in 926 infants born
pre-term and randomly assigned to receive donated
banked breastmilk
or pre-term formula in one trial, or standard term
formula or pre-term formula in a second trial,
as sole diet or
as supplement to mother's milk in both trials.
216 participants were followed up to age 13-16
years.
Adolescents who
had been randomised to banked breastmilk had a
lower C-reactive protein (CRP, a measure of the
inflammatory
process associated with arteriosclerosis) and LDL
to HDL (high density lipoprotein, associated with
a lower
risk of heart disease) ratio than those given pre-term
formula. A greater proportion of human milk intake
in infancy was associated with lower ratios of
LDL to HDL
and of other lipoproteins associated with heart
disease, independent of gestation and potential
confounding
factors. The authors conclude that their data provide
experimental
evidence for the long-term benefits of breastmilk
feeding on the risk of arteriosclerosis.
Diabetes
Ziegler AG, Schmid S, Huber D, Hummel M, Bonifacio E.
Early infant feeding and risk of developing
type 1 diabetes-associated autoantibodies. JAMA 2003;290:1721-8
To determine whether breastfeeding duration, food
supplementation, or age at introduction of gluten-containing
foods influence
the risk of developing auto-antibodies against islet
(the insulin-producing tissue of the pancreas), a study
of 1,610 children was conducted from 1989 to 2003 in
inpatient/outpatient clinics in Germany. Blood samples
were obtained at birth, age 9 months, 2, 5, and 8 years.
Dropout rate was 14.4% by the age of 5 years. Breastfeeding
data were obtained by questionnaires, and food supplementation
data by family interview. Life-table islet auto-antibody
frequency was 5.8% by the age of 5. Reduced total or
exclusive breastfeeding duration did not significantly
increase the risk of developing islet auto-antibodies.
Food supplementation with gluten-containing foods before
the age of 3 months, however, was associated with a
significant, four-fold increase in islet auto-antibody
risk. Children
who first received gluten-containing foods after the
age of 6 months did not have increased risks for islet
or celiac disease (a severe lifelong disease due to
gluten intolerance) auto-antibodies. The authors
conclude that
ensuring compliance to WHO infant feeding guidelines
is a possible way to reduce the risk of developing
type 1 diabetes auto-antibodies.
Sadauskaite-Kuehne
V, et al. Longer breastfeeding is an
independent protective factor against development
of type 1 diabetes mellitus
in
childhood. Diabetes Metab Res Rev 2004;20:150-7
Is early nutrition a risk factor for diabetes?
A case-control study was carried out in Sweden
on 517 children and
in Lithuania on 286 children 0 to 15 years old
with newly
diagnosed type 1 diabetes mellitus, a type of that
starts in childhood. The study included three age-
and sex-matched
health controls. In Sweden, exclusive breastfeeding
longer than 5 months (longer than 2 months in Lithuania),
total
breastfeeding longer than 7 or 9 months, and breastfeeding
substitution later than the 3rd month were shown
to be protective against diabetes when adjusted
for all
other
factors. The authors advise that postponing introduction
of breastmilk substitutes might protect children
from type 1 diabetes.
Constipation
Aguirre AN, Vitolo MR, Puccini RF, de Morais MB.
Constipation in infants: influence of
type of feeding and dietary
fiber intake. J Pediatr
(Rio J) 2002;78:202-8
Breastfeeding may be a protective factor against
constipation in the first 6 months of life. This
is the conclusion
drawn after a study of 275 infants consecutively
enrolled in two primary care clinics in the city
of Embu, near
São Paulo. Constipation was found in 25% of them;
the prevalence was higher between 6 and 24 months (39%)
than in the first 6 months (15%). The statistical analysis
demonstrated that formula-fed infants were 4.5 times
more liable to develop constipation than infants who
were predominantly breastfed. The daily dietary fiber
intake was similar among the constipated and non-constipated
infants. Constipation was defined by the elimination
of hard stool associated with one of the following: painful
or difficult defecation, hard or round cracked stools
and less than three defecations a week.
Andiran F, Dayi S, Mete E. Cows
milk consumption in constipation and anal fissure
in infants and
young children. J Paediatr
Child Health 2003;39:329-31
This study confirms the above findings using a
different research design. 30 infants and young
children aged
4 months to 3 years with chronic constipation
and anal fissure (surgical causes were excluded)
were
compared
with 30 children in the same age range with normal
bowel
habits. The mean daily consumption of cow’s milk
was significantly higher in the former (756 ml, range
200-1500) than in the latter group (253 ml, range 0-1000).
Children with chronic constipation and anal fissure were
breastfed for a significantly shorter period (5.8 months,
range 0-18) than the other children (10.1 months, range
2-24).
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