In the last post, Kathy Dettwyler asked two good questions about
birth order and dioxins and about why our kidneys can't excrete
dioxin. (Sorry I deleted your questions exactly as you had asked
them):
Yes, first borns get a much bigger dose. As far as I know, no one
has looked to see if their health outcomes are worse. Any study
worth its salt would have to compare health differences among
differently ordered siblings in both breastfed and formula-fed
families. Birth order, independent of method of infant feeding,
probably alters health risks of various kinds.
Question 2: the reason that dioxin can't be excreted in urine is
because it is not water soluble. Our detoxifying enzymes, which try
mightily to metabolize fat-soluble contaminants into water-soluble
contaminants specifically so they can be excreted via the kidneys,
can't really make a dent in a dioxin molecule because it's so
symmetrical. (Well, they can but it happens so so slowly that we all
accumulate dioxins from our daily diets faster than we can excrete
them, which is why the older you get, the more dioxins you have.)
Some researchers have argued that people who diet just end up
concentrating their dioxin burdens further, but this is a deductive
conclusion, not an evidence-based finding. Measuring dioxin in human
body tissue is so expensive, very few researcher are doing it.
As an aside: A lot of pesticides in use today are water-soluble--or
at least our bodies can make them so--and so urine is a good bodily
fluid to take a look at if you want to estimate exposure. For
example, most U.S. children have in their urine traces of
organophosphate pesticides, which indicate ongoing, daily exposures
to this class of contaminants. (pet flea collars, pest contol in
schools, day care centers, athletic fields, playgrounds, and home and
garden).
But dioxin doesn't show up in urine, which is why breast milk, with
its 4 percent butterfat, is a good place to look for it.
warmly, Sandra
p.s. Annelies, do you agree with me here?
--
--
Sandra Steingraber, Ph.D.
Visiting Assistant Professor
Program on Breast Cancer and Environmental Risk Factors
110 Rice Hall
Cornell University
Ithaca, NY 14853
[log in to unmask]
www.steingraber.com
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