1. Professor Stewart Forsyth, Consultant Paediatrician,
studied 543 children and their parents from lower
and higher socio-economic groups. Health out-
comes studied were gastroenteritis, respiratory illness
and ear infections up to one year of age, and blood
pressure, respiratory illness and body composition at
seven years. (1)
In the lower socio-economic group the outcome for
the breastfed children was similar to or significantly
better than the formula fed group in the higher
social class category. This was evident for each of the
health outcome measures.
Respiratory illness
The probability of respiratory illness occurring at any
time in childhood is significantly reduced if a child
is exclusively breastfed and receives no solid food
before 15 weeks. (2)
One month of exclusive breastfeeding conferred pro-
tection against allergic food intolerance and respira-
tory allergens. Protection was evident in children up
to 17 years. (3)
Babies fed milk other than breastmilk before four
months of age are at significantly increased risk of
asthma. (4)
Cardiovascular disease and risk factors in later life
Formula fed infants have a prevalence of obesity of
4.5% at age 5 and 6 years, compared with a preva-
lence of 2.8% in breastfed children. (5)
Children who have been exclusively breastfed during
the first ten days of life had healthier lipid profiles and
glucose tolerance at age 50. (6)
Breastfeeding is associated with lower systolic blood
pressure at age 7. Because blood pressure tracks
from childhood to adult life with amplification of
early differences, the blood pressure difference is
likely to be substantially greater in adult life. (7)
In a non-hypertensive population the potential ben-
efit of breastfeeding is greater than the benefit from
all other non-pharmacological interventions, such as
weight loss, salt restriction or exercise. (8)
Adolescents who were born premature and who
were fed breastmilk in infancy have a 14% reduc-
tion on their ratio of LDL to HDL cholesterol. A dose
response relationship was found. (9)
© Health Service Executive 2008
FACTSHEET
01The Evidence for Breastfeeding
Breastfeeding
Information for GPs and Pharmacists
The Evidence for Breastfeeding
Breastfeeding reduces health inequalities - Children from less favourable social
circumstances who receive breastmilk and who experience later introduction to
solid food have health outcomes that are similar to or better than the health out-
comes of more affluent children who receive formula milk and early introduction
of solid food.

2. Breastfeeding
Information for GPs and Pharmacists
© Health Service Executive 2008
Infectious disease
Formula feeding is associated with increased in-
cidence of lower respiratory tract infection, otitis
media, gastroenteritis and urinary tract infection. The
protective effect of breastfeeding extends beyond
the period of breastfeeding. (10, 11)
Diabetes
The relative risk of a child developing non-insulin de-
pendent diabetes if they are formula fed is 2.4 times
that of a breastfed child. (12)
Obesity
The American Academy of Paediatrics issued a policy
statement on‘Prevention of Paediatric Obesity’(see
www.aap.org). It identifies lack of breastfeeding as
one of the risk factors for obesity and recommends
the support, encouragement and protection of
breastfeeding as a preventative measure.
Babies who are breastfed for at least a year are leaner
than those weaned earlier. Babies who have never
been breastfed are more likely to become over-
weight. (13)
A meta-analysis on existing studies on duration of
breastfeeding and risk of overweight strongly sup-
ports a dose dependent association between longer
duration of breastfeeding and decrease in risk of
overweight. (14)
Cognitive development
A study has found that in the presence of a particular
gene in the child (FADS2), breastfeeding can raise
IQ by an average of seven points. FADS2 is involved
in the way the body processes fatty acids in the diet
and has two genotypes – C and G. 90% of the popu-
lation carry the C version which is associated with
better IQ scores in breastfed children. The outcomes
in the 10% who carry the G version were made no
worse by breastfeeding. (15)
Formula feeding is associated with significantly lower
scores for cognitive development than is breastfeed-
ing after adjusting for appropriate co-factors. Differ-
ences were greater for low birth weight babies and
increased with increased duration of breastfeeding.
(16)
Cognitive effects of breastfeeding are thought to be
due to the presence of long chain polyunsaturated
fatty acids (LCPUFAS) in breastmilk. Newborns cannot
synthesise LCPUFAS which are necessary for opti-
mum development of neural tissue. The addition of
LCPUFAS to formula milk has not been shown to have
an enhancing effect on the IQ of preterm infants. (17)
Developmental delay
Breastfeeding is associated with reduced risk of de-
velopmental delay at nine months of age. This effect
is not due to advantaged social position or parenting
style. (18)
Maternal health
The relative risk of breast cancer is reduced by 4.3%
for every 12 months of breastfeeding. Having been
breastfed is associated with a lower risk of pre-and
post-menopausal breast cancer. (19)
The Evidence for Breastfeeding

3. Breastfeeding
Information for GPs and Pharmacists
© Health Service Executive 2008
References
1. UK Baby Friendly Initiative Annual Conference
2004. Influence of infant feeding practices on
health inequalities in childhood. Professor Stew-
art Forsyth, Consultant Paediatrician, Ninewells
Hospital and Medical School, Dundee. Abstract
available from www.babyfriendly.org.uk
2. Wilson AC, Forsyth JS, Greene SA, Irvine L, Hau C,
Howie PW. Relation of infant diet to childhood
health: seven year follow up of cohort of children
in Dundee infant feeding study. BMJ 1998;316:21-5.
3. Saarinen UM, Kajosaari M. Breastfeeding as prophy-
laxis against atopic disease: prospective follow up
study until 17 years old. Lancet 1995;346:1065-9
4. Oddy WH, et al. Breastfeeding and respiratory
morbidity in infancy: a birth cohort study. Arch Dis
Childhood 2003; 88:224-8.
5. Von Kries R, Koletzko B, Sauerwald T, et al. Breast-
feeding and obesity: cross sectional study. BMJ
1999:319;147-50
6. Ravelli AC, Van der Meulen JHP, Osmond C, Barker
DJP, Blekes OP. Infant feeding and adult glucose
tolerance, lipid profile, blood pressure and obesity.
Arch Dis Childhood 2000:82;248-52
7. Wilson AC, Forsyth JS, Greene SA, Irvine L, Hau C,
Howie PW. Relation of infant diet to childhood
health: seven year follow up of cohort of children
in Dundee infant feeding study. BMJ 1998;316:21-5.
8. Ebrahim S, Smith GD. Lowering blood pressure:
a systematic review of sustained effects of non-
pharmacological interventions. J Pub Health Med
1998;20:441-8.
9. Singhal et al. Breast milk feeding and lipoprotein
profile in adolescents born preterm: follow-up of a
prospective randomised study. Lancet. 363: 1571-
78
10. Howie PW, Forsyth JS, Ogston SA, Clark A, Florey
CduV. Protective effect of breastfeeding against
infection. BMJ 1990:300; 11-6
11. Pisacane A, Graziano L, Mazzarella G, Scarpelliono
B, Zona G. Breastfeeding and urinary tract infec-
tion. J Paediatr 1992:120;87-9
12. Petitt DJ, Forman NR, Hanson RL, Knowler WC,
Bennett PH. Breastfeeding and incidence of NI-
DDM in Pima Indians. Lancet 1997:13:203-8
13. Burke V et al. Breastfeeding and Overweight
Longitudinal Analysis in an Australian Birth Cohort.
J Ped.
(2005)147:56-61
14. Harder T et al. Duration of Breastfeeding and risk
of Overweight: a meta-analysis. Am J Epidemiol-
ogy 162:397-403
15. Capsi A. et al. (2007) Moderation of breastfeeding
effects on the IQ by genetic variation in fatty acid
metabolism. PNAS. 10. 1073
16. Anderson EW, Johnstone BM, Remax DT. Breast-
feeding and cognitive development (A meta-
analysis of 20 studies). Am J Clin Nutrition 1999:
70;525-35.
17. Fewtrwll MS et al. (2002) Double-blind ran-
domised control trial of LCPUFAS in formula fed to
preterm infants. Pediatrics 110:73-82
18. Collaborative Group on Hormonal Factors in
Breast Cancer. Breast cancer and breastfeeding:
collaborative reanalysis of individual data from 47
epidemiological studies in 30 countries, includ-
ing 50,302 women with breast cancer and 96,973
without the disease. Lancet 2002:360;187-95.
19. Sacker A. et al. Breastfeeding and Developmental
Delay. Findings from the Millenium Cohort Study.
Pediatrics. (2006) 118: e682-689
The Evidence for Breastfeeding