wehave - that is a good question. i think BMA are not so concerned about what gets into breastmilk, but of course people like LLL and other bf orgs. talk about the dangers of chemicals that can get into breastmilk.
it is important that bf mums don't think that what they eat will be dangerous to their babies. breastmilk is safe, even with the few chemicasl that WILL get into your milk as a result of the food you eat and what you put on your body, the risks are small.
i totally get your logic though, because some of what a mother eats will get into her bloodstream and into the baby. that is why it is important to be careful about what meds. we take when bf.
if any one is concerned about this, please check the www.kellymom.com website, it has a detailed list of what meds. are safe when bf.
as for food, i guess unless you are eating vast quantities of mercury laden fish, there is not that much danger when bf. as most foods are safe.
chemicals we put on our bodies also get into breastmilk, in small quantities though. i gave up on perfume and hairdyes and some other things with masses of chemicals in when i was bf. even now although i no longer bf, i have become much more aware of chemicals in beauty products, shampoos, etc. i tend to buy organic products or stuff with fewer chemicals in them. i buy only organic shampoos and soaps, etc for ds.