"The problem is a lot of people bandy around research about breastmilk as though it is something magical that can protect you and your children against all ills "
Actually in 'bandying about research' you are doing the very opposite of implying that breastmilk is 'magical'. What you're doing is flagging up the evidence and inviting people to take note of it. People who bother to read the research will have a reasonable and realistic understanding of what health benefits may come from breastfeeding.
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Most people who engage in discussions on this issue on mumsnet haven't read any studies at all. At most they will have skim read a couple of paragraphs of a report from the Daily Mail. Those people on this site who argue against breastfeeding having any significant benefits, and make the most complaints about the quality of research, tend to be the ones who've done the least reading.
"It isn't . If you breastfeed for 18 months over your life time , you will reduce the chance of developing breast cancer . If you drink a bottle of wine a week and are overweight , then that 18 months spent breast feeding wont have as protective an influence"
Sorry - are you saying that breastfeeding no longer reduces your chance of experiencing breast cancer if you drink or are overweight?
Or are you saying that that being fat and drinking a bottle of wine a week offsets the risk reduction offered by prolonged breastfeeding, resulting in an individual who has done all of these things having the same chance of getting breast cancer of someone who does none of these things?
If you are saying the first - you are simply wrong.
If you are saying the second - you are making an even stronger case for breastfeeding for women who wish to reduce their lifetime risk of breast cancer.