Six months of exclusive breast feeding: how good is the evidence?

BMJ 2011; 342 doi: (Published 13 January 2011) Cite this as: BMJ 2011;342:c5955

Why revert to 4 months?

The most useful aspect of this paper is the authors' acknowledgment
that science does not know when and what normal foods can most safely be
introduced to infants. (And I would add, there is little science-based
practical guidance, other than the WHO literature, on the subject of
complementary food for the breastfed infant). Yet despite this, the
authors seem to argue for reversion to the 1980s 4 month guideline, as
though this has been proven safe by common or even long term usage
(ignoring the epidemics of allergy and diabetes and obesity and
neurological problems in children wherever artificial feeding has become
normative). And they seem unaware that the 1980 AAP 4-6 months
recommendation for the introduction of solid foods to all infants was not
based on evidence of benefit or safety. Rather, it was an attempt to end
commercially-driven absurdly early introduction of foods, and it came in
the wake of the CHO-Free and other formula recalls and parental

A letter from the AAP Committee Chairman made this clear. Challenged
as to why four months was chosen when the physiological markers used to
justify the recommendation [disappearance of the extrusive reflex, IgA
production, teeth, ability to indicate satiety etc] emerged between five
and seven months, he replied: 'Trying to convert from previous practices
of feeding solids at 1 month of age to the present recommendations must be
done step-wise. A compromise was felt to be necessary. For breastfed
infants there seems no advantage and some disadvantage to early
supplements. When one uses an artificial formula, no matter how good, one
must beware of possible missing ingredients. Weighing advantages and
disadvantages, the Committee on Nutrition felt that 4 to 6 months of age
was reasonable with present evidence.' [Barness reply to Ganelin,
Pediatrics (1981) 67:166.]

To be safe, in short, the diet of the artificially fed baby needs to
widen before in utero stores of nutrients are exhausted. And this time is
earlier than infant development would suggest is logical for the addition
of solid foods to the breastfed infant, who in fact is disadvantaged by
such early introduction.

For the diet of the breastfed child does not need to widen so early
(unless maternal supply is inadequate, as it often is due to poor
management). Breastmilk has evolved to contain all that a child needs for
normal physical and mental development, and is the essential supportive
medium whereby the child's immune system samples both normal family diet
and environmental challenges. We know that breastfed children more readily
accept a wide variety of flavours: the bland sugary taste of regular
formula, or the metallic flavours of others, work against normal taste
development. We know that the foods most likely to be suggested for
western breastfed babies between 4 and 6 months are artificial formula, or
lowfat low protein cereals and single vegetables. We know, as Fewtrell et
al agree, that artificial formula increases the risk of infection. We
know that growth faltering and iron deficiency can result from vegetable
foods that interfere with breastmilk absorption and utilization: pears
chelate iron, eg. We know that the mid to late 20th century belief that
breastmilk was often (rather than rarely ) inadequate for a child to 6
months was largely due to early Pritikin-type supplementary foods (and
poor growth charts).

There are a few breastfed babies who need more than their mothers can
provide. WHO and every nation adopting the WHO recommendation understood
this. The concept of 'around 6 months' does not preclude individualised
care of babies not thriving on breastmilk alone. But does that mean giving
formula and increasing infection risk and decreasing maternal breastmilk?
What is it safest for parents to give if not enough maternal breastmilk is
available? When? WHO suggests home prepared multi-mixes of family foods,
western nations after 1980 single vegetable foods over lengthy periods of
time. The reality can be little jars of sweet stuff because young babies
reject other tastes. Yet the accepted mantra for dietary safety is variety
and moderation of intake, which accords with the WHO strategies for
complementary feeding. How do we implement that where almost universal
neonatal exposure to bovine protein has undermined normal immune and gut
development? It will be a long time before convincing answers emerge.
Meanwhile, do we support breastfeeding mothers to increase their
production, revive cross-nursing, look for culturally embedded knowledge,
use foods the mother tolerates, or trust patent foods? All these options
are currently in play.

Helpfully too, Fewtrell et al seem to endorse the SACN comment that
there is no evidence base to support a change to 6 months' exclusive
formula feeding. There never was. WHO never comments on patented
industrial substitutes for breastmilk. Its 6 month recommendation was
solely for breastfed infants, and is supported by generations of women who
have successfully breastfed solely for 6 months of more, whose healthily
fat babies morph into lean toddlers. Industry was strongly opposed to, and
slow to accept, the changed recommendation, perhaps because aware of the
deficiencies and excesses on record, and the difficulty of producing an
adequate substitute for a milk whose unique properties are only now being
uncovered. To have all infants widening their diet at four months reduces
the likelihood of formula deficiencies becoming apparent without
disturbing the delusion of formula being equivalent to breastmilk. Since
parents know if their child is breastfed or not, why not 4 months for AF
and 6 months for BF babies? Because industry might not like it? Surely

A referenced and extended version of this letter is available from

Competing interests: No competing interests

18 January 2011
Maureen K Minchin
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