Dear Colleagues,
If we, as breastfeeding experts, have an opportunity to comment about
reports of toxins in milk, I think it’s important to avoid knee-jerk
responses saying “there’s bad stuff in formula too.” We’ll never win
that argument. The evidence indicates that human milk does have higher
levels of POPs (persistent organic pollutants) than cows’ milk. This
makes sense, because cows are vegetarians and don’t eat other animals
that have eaten other smaller animals that have eaten other smaller
animals, increasing the body burden of toxics with each step in the food
chain. (Fish are a good example of this accumulating effect.)
Here is some background material that I gathered this week about the EWG
(Environmental Working Group) and the toxins (AKA ”body burdens”) issue.
I. Info about WABA’s link with the environmental community:
Brief history: As an international treaty on the topic of POPs was being
developed, breastfeeding advocates and environmental advocates began
working together to address the issue of how we should speak about
toxins in human milk. They looked for ways that environmental groups can
use information from studies that have measured toxins in milk without
subverting breastfeeding promotion. Marian Tompson of LLLI and Susan
Siew of WABA addressed a meeting of environmental groups in Bonn in
2000; later that year Susan and Penny Van Esterik attended an
intergovernmental negotiating committee (INC) meeting in Johannesburg.
Susan was at the May 2001 meeting in Stockholm where the Stockholm
Convention was signed. The Stockholm Convention is an international
treaty that follows up on the Earth Summit that was held in Rio in 1992.
It is an attempt to rein in and ultimately halt the proliferation of
toxic chemicals.
A joint statement was drafted by WABA and IPEN (International POPs
Elimination Network) at a special meeting in Bolinas, California, in
2001 and further discussed at the LLL conference in Chicago that year.
Penny's monograph "Rights, Risks and Regulation: communicating
contaminants and infant feeding" was introduced at the conference. You
can find it online at
http://www.waba.org.my/RRR/penny1b.htm
(I think it's worth a trip to the WABA website just to see the "Corridor
of Bellies" silent demonstration that the NGOs staged at the INC
meeting. Click on "Breastfeeding and Environmental Social Justice
Advocates at Work" in Penny's document.)
You can see the joint statement on the WABA website at
http://www.waba.org.my/RRR/joint.pdf
Why are these documents relevant? They are the result of serious joint
effort by environmental advocates and breastfeeding advocates to find
words to express the dangers we face as a global community—without
undermining anyone's efforts to promote and support breastfeeding. In
this arena, you can see that finding the right words is a key to
PROTECTING breastfeeding--one of the Innocenti strategies.
II. Info about the EWG (Environmental Working Group)
Word came out on Lactnet in February 2003 that EWG was doing a project
to test human milk for toxic substances. I queried a contact of mine
from a (non-radical) environmental group in California, who told me
that, in her dealings with EWG, the group was sensitive to the issues of
how to disclose findings so as not to undermine breastfeeding. Such
sensitivity is important, but it is only the first step, because then
comes. . . .
III. What the media does with the information
This is a crucial aspect of the problem. Look at it as a series of
steps, like in the game of “Gossip” that I used to play at birthday
parties. (In my kids’ generation, it was “Whisper Down the Lane.”)
1. A study looks for toxic substances in human milk (because that’s an
effective way to monitor toxic body burdens)
2. The study findings are announced in a press release as “All human
tissues carry a body burden of toxic substances, as shown by a study of
human milk.”
3. The media interpret the findings as “Human milk is toxic!!!!!”
So what we say in reaction to such announcements can be an important
counter-weight to potential mis-interpretation of the study findings.
It is important to go back and look at what the researchers really said
in their press release. Also, if we can, to see what the real
conclusions were in their study. One announcement that I read said,
“these levels in breast milk indicate that babies in the womb are
exposed to high levels during crucial brain development.” That’s the
important point!
ALL babies are exposed before they ever have a taste of human milk, and
they are exposed whether or not they are later breastfed.
If we need a sound bite response to this news item, I think that’s it.
I also had some time yesterday to look carefully at the article,
Ribas-Fitó N, E Cardo, M Sala, ME de Muga, C Mazón, A Verdú, M
Kogevinas, JO Grimalt, J Sunyer (2003) Breastfeeding, exposure to
organochloride compounds, and neurodevelopment in infants. Pediatrics
(on line) 111:5, May 2003, e580-85.
http://www.pediatrics.org/cgi/content/full/111/5/e580.
The study looked at 84% of the babies born over a two-year period in a
small area in Spain where the population had been exposed to various
organochloride pollutants for over 40 years because of a factory in the
area. Adults in the area had the highest levels of hexachlorobenzene
(HCB) ever reported, and cord blood samples in babies were also very
high in HCB. The study reported on p,p’DDE (dichlorodiphenyl
dichloroethylene), HCB, and PCB (polychlorinated biplenyl)—not on the
PBDEs of the US flame-retardant study that’s in the news now.
In this study, babies were divided into “short-term breastfeeding” (2-16
weeks) and “long-term breastfeeding” (over 16 weeks). 16 weeks was the
median length of breastfeeding in this population, so I assume that’s
why they chose 16 weeks---not for any clinical reason. Half the nursing
babies nursed more than 16 weeks, and half nursed less than 16 weeks.
The babies were also divided according to their cord blood levels of
p,p’DDE, indicating low or high prenatal exposure to the chemical.
Here is a modified table that help you see the findings. The numbers are
the mean test scores for the groups of babies. I rounded the scores and
did not show the SD. The population mean scores on these standard tests
is 100. The groups were controlled for many confounders, such as
maternal age, paternal occupation, maternal smoking or alcohol use,
maternal education, baby’s gender and attendance at kindergarten (I
assume this is group care, since we’re talking about 1 year olds.)
___________________________________________________________
bf > 16 wks bf < 16 wks formula fed
mental score
low cord blood level 111 103 101
high cord blood level 107 97* 101
psychomotor score
low cord blood level 97 86 92
high cord blood level 91 81* 87
* P<.05 compared with babies with low cord blood levels and bf >16
weeks.
_____________________________________________________________
The babies were tested on mental and psychomotor development at 1 year
of age. Babies with high p,p’DDE levels in cord blood had lower scores
on both developmental tests, regardless of feeding method, compared to
babies with lower cord blood levels. Babies who breastfed over 16 weeks
had better scores than babies who breastfed less than 16 weeks and
babies who had no breastfeeding, regardless of cord blood p,p’DDE
levels—that is, long-term breastfeeding helped raise developmental
scores in all groups of babies, no matter how much prenatal exposure
they had.
That’s the good news.
What concerns me is the report that, for the group of babies with high
cord blood levels of toxics, the short-term breastfeeding group scored
significantly lower than the long-term breastfeeding group, with the
formula fed group in a middle position. The difference was statistically
significant only when comparing long-term bf to short-term bf…but with
the formula babies scoring better than the short-term breastfed babies,
people could conclude that, if you’re not going to breastfeed for at
least 16 weeks, and if you think you might have had high exposure to
environmental toxins (because you live in the USA, for instance!), or if
you “just want to be safe,” formula could be a better choice than
breastfeeding.
These authors also report, citing another article which they have
submitted for publication, that “we have observed in the infants of this
population that those who breastfed increased their concentrations of
organochlorine chemicals during the first weeks of life.” Their next
sentence, is “Long-term breastfeeding, however, seems to be beneficial
to the infant.”
I think we need to be aware of this article. There are many things to
consider. For instance,
1. This was a special population, with long-term exposure to a toxic
environment. Still. . . we need to be able to make recommendations for
every woman, not just the lucky ones who can limit their exposure. AND,
we are all “living downstream” these days.
2. We don’t know HOW the breastfed babies were breastfed—only how long
they had any breastfeeding. If the short-term breastfed group were
partially breastfed more and earlier and longer than the long-term
group, that might affect how they handled any toxins they took in by the
GI route. Think of the effect of mixed feeding in HIV-exposed babies,
for instance, where true exclusive bf is protective and partial bf is
risky.
3. It appears to me that the 16 week figure was chosen for statistical
reasons, not because there’s something magical about the age of 16
weeks. Maybe there are age-related changes in the baby’s GI tract that
we don’t know about. It could be that the critical period to get a
protective effect of “long-term breastfeeding” is really 12 weeks or 9
weeks. I know very little about statistical methods…so all I can do is
ask the question.
I know that we all want breastfeeding to be the best choice in every
circumstance. I just want to be sure we examine the available evidence
and make an evidence-based recommendation. Where the evidence is too
scanty to base a recommendation on, we need to know this, and
acknowledge it. In the case of the Ribas-Fitó article, I think it
indicates that we need to know a lot more about short-term breastfeeding
before we endorse any notion that formula would be a better choice.
Cheers,
Chris
Chris Mulford, RN, IBCLC
LLL Leader Reserve
working for WIC in South Jersey (Eastern USA)
Co-coordinator, Women & Work Task Force, WABA
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