If you're confused about how to take care of yourself (and your children), I don't blame you. The public health community seems to change their opinion every 5 minutes, about everything from mammograms to optimal vitamin D levels. And now, they can't seem to agree about how long mothers should exclusively breastfeed. Mind you, no one is talking about whether or not "breast is best." That hasn't changed. What is up for debate, however, is when solid foods should be introduced.
In 2001, the World Health Organization (WHO) established a guideline, advocating 6 months of exclusive breastfeeding in both industrialized as well as developing nations. This guideline continues to be borne out by research. For example, in early 2010, a study was published in the journal Pediatrics which showed that exclusive breastfeeding to 6 months was healthier than to 4 months, in terms of reducing infectious diseases. But now a group of scientists, publishing in the British Medical Journal, are saying that health issues that were not taken into account at the time of the WHO's guidelines need to be considered, and that in fact exclusive breastfeeding past the age of 4 months is more detrimental than beneficial. Harmful effects include an increased risk of celiac disease, as well as iron deficiency.
I'm guessing that this is going to stir up some controversy.