The optimal duration of exclusive breast feeding is a subject of continuing debate. Most recently Fewtrell and colleagues1 have challenged the evidence underpinning the 2002 World Health Assembly endorsement of the recommendation that in both developing and developed countries exclusive breast feeding should be for a minimum of 6 months.2 They questioned whether there was sufficient evidence to support the change from 4 to 6 months in developed countries and they also suggested that the 6-month policy could be disadvantageous to some infants.

Questioning the validity of any aspect of breast feeding policy generates widespread media, professional and public interest and with the possibility of misinterpretation there is a potential risk that the key health message of breast milk being the nutrition of choice for newborn babies may be undermined. It is therefore important that the specific issue that has been raised is set within the wider context of breast feeding and health benefits. In relation to duration of exclusive breast feeding, there appears to be scientific and clinical consensus that in developing countries the optimal duration of exclusive breast feeding is 6 months. For developed countries there is a strong consensus of opinion, based on evidence from the UK and other developed countries, that there are important health benefits from exclusive breast feeding for a minimum of 4 months.3 However, there continues to be a division of opinion on the strength of evidence to support the World Health Organization (WHO) recommendation that in developed countries the minimum duration of exclusive breast feeding should be extended from 4 to 6 months.1

The WHO media response to the Fewtrell paper contained a reaffirmation of their recommendation that mothers worldwide should exclusively breast feed their infants for the first 6 months of life.4 Their evidence is underpinned …