Some facts - all backed up by evidence - from the Kelly Mom factsheet
Using the words KellyMom and Fact Sheet in the same sentence is an oxymoron, that is a special interest site dedicated to pro BF and EBF and run by a self confessed lactivist. They also tend to use research that is specific out to 6, maybe 12, months and then assume its true out far longer.
The only "circular" argument is that these sites tend to cross-use and re-use the same (frequently out of date, often already debunked) data.
"Extensive research on the relationship between cognitive achievement (IQ scores, grades in school) and breastfeeding has shown the greatest gains for those children breastfed the longest."
Beastfeeding Children does not make them more Intelligent (Latest 2012 research) Reviews show studies' conflate results with parental intelligence.
"In the second year (12-23 months), 448 mL of breastmilk provides:
29% of energy requirements
43% of protein requirements
36% of calcium requirements
75% of vitamin A requirements
76% of folate requirements
94% of vitamin B12 requirements
60% of vitamin C requirements
-- Dewey 2001"
You could as easily reel off the stats for a Weetabix. It's food. Any food has nutritional value and it goes up and down depending on how much of it you eat. The unavoidable truth remains that there is not enough breast milk to feed a growing child, so you have to introduce other foods after 6 months or so, and at that point b/f as a % of intake tails off, and the importance of the new nutrients overtakes it over time.
"Nursing toddlers between the ages of 16 and 30 months have been found to have fewer illnesses and illnesses of shorter duration than their non-nursing peers (Gulick 1986)."
Not necessarily - exclusive breastfeeding can in fact be bad for health BMJ, 2011
Antibodies are abundant in human milk throughout lactation" (Nutrition During Lactation 1991; p. 134). In fact, some of the immune factors in breastmilk increase in concentration during the second year and also during the weaning process. (Goldman 1983, Goldman & Goldblum 1983, Institute of Medicine 1991)."
They increase in concentration because the volume of milk goes down but the net input is still lower...
There is also increasing evidence that extended breastfeeding causes poorer response to vaccines and increases sensitivity to allergies (Journal of Nutrition, 2008 ).
In fact the one thing that has risen as breastfeeding rates have risen in the same cohort groups in OECD countries is childhood allergies. You may wish to keep tabs on that research as it carries on (eg BMJ 2007).
The whole EBF story is based on a lot of out of date data (if it was ever data) in the main, or people have misinterpreted WHO and UNICEF advice for developing countries and assumed it is as true in the first world.
I suspect the pro-breastfeeding pendulum has now swung too far, and will now start to swing back as increasing evidence of the downsides comes in.
Moderation in all things is probably the best approach.