I'm posting yet another article on soy and it's possible negative effects
because I received numerous emails (some queries, some positive, and some
a
bit hostile regarding my suggestion that soy was not an appropriate
substitute for human milk). There are many more, but I'll contain
myself.
For those interested in this topic, I highly encourage that you go to the
original articles. They are full of interesting info.
Maximum Relevance:Phytoestrogens in soy-based infant foods:
concentrations,
daily intake, and possible biological effects.
Proc Soc Exp Biol Med 1998 Mar;217(3):247-53 (ISSN: 0037-9727)
Irvine CH; Fitzpatrick MG; Alexander SL [Find other articles with these
Authors]
Animal and Veterinary Sciences Group, Lincoln University, Canterbury, New
Zealand. [log in to unmask]
Exposure to estrogenic compounds may pose a developmental hazard to
infants.
Soy products, which contain the phytoestrogens, genistein and daidzein,
are
becoming increasingly popular as infant foods. To begin to evaluate the
potential of the phytoestrogens in these products to affect infants, we
measured total genistein and daidzein contents of commercially available
soy-based infant formulas, infant cereals, dinners, and rusks. We also
assayed phytoestrogens in dairy-based formulas and in breast milk from
omnivorous or vegetarian mothers. In most cases, the glucoside forms of
the
phytoestrogens were hydrolyzed before separation by HPLC. Mean (+/-SEM)
total genistein and daidzein contents in four soy infant formulas were
87+/-3 and 49+/-2 microg/g, respectively. The phytoestrogen content of
cereals varied with brand, with genistein ranging from 3-287 microg/g and
daidzein from 2-276 microg/g. By contrast, no phytoestrogens were
detected
in dairy-based infant formulas or in human breast milk, irrespective of
the
mother's diet (detection limit = 0.05 microg/ml). When fed according to
the
manufacturer's instruction, soy formulas provide the infant with a daily
dose rate of total isoflavones (i.e., genistein + daidzein) of
approximately
3 mg/kg body weight, which is maintained at a fairly constant level
between
0-4 months of age.
Supplementing the diet of 4-month-old infants with a single daily serving
of
cereal can increase their isoflavone intake by over 25%, depending on the
brand chosen.*** This rate of isoflavone intake is much greater than that
shown in adult humans to alter reproductive hormones. Since the available
evidence suggests that infants can digest and absorb dietary
phytoestrogens
in active forms and since neonates are generally more susceptible than
adults to perturbations of the sex steroid milieu, we suggest that it
would
be highly desirable to study the effects of soy isoflavones on
steroid-dependent developmental processes in human babies.***
--Chris Hafner-Eaton, PhD, MPH, CHES, IBCLC [log in to unmask]
€€€INFANT CUISINE AND MOTHER CARE: LACTATION CONSULTING & PERINATAL
CARE€€€
Here is another article, this one published in LANCET (the other was in
the
AM J. Cl Nutrition)
Maximum Relevance:Exposure of infants to phyto-oestrogens from soy-based
infant formula [see comments]
Lancet 1997 Jul 5;350(9070):23-7 (ISSN: 0140-6736)
Setchell KD; Zimmer-Nechemias L; Cai J; Heubi JE [Find other articles
with
these Authors]
Clinical Mass Spectrometry Center, Children's Hospital Medical Center,
Cincinnati, Ohio 45229, USA.
BACKGROUND: The isoflavones genistein, daidzein, and their glycosides,
found
in high concentrations in soybeans and soy-protein foods, may have
beneficial effects in the prevention or treatment of many
hormone-dependent
diseases. Because these bioactive phyto-oestrogens possess a wide range
of
hormonal and non-hormonal activities, it has been suggested that adverse
effects may occur in infants fed soy-based formulas. METHODS: To evaluate
the extent of infant exposure to phyto-oestrogens from soy formula, the
isoflavone composition of 25 randomly selected samples from five major
brands of commercially available soy-based infant formulas were analysed,
and the plasma concentrations of genistein and daidzein, and the
intestinally derived metabolite, equol, were compared in 4-month-old
infants
fed exclusively soy-based infant formula (n = 7), cow-milk formula (n =
7),
or human breast-milk (n = 7). FINDINGS: All of the soy formulas contained
mainly glycosides of genistein and daidzein, and the total isoflavone
content was similar among the five formulas analysed and was related to
the
proportion of soy isolate used in their manufacture. From the
concentrations
of isoflavones in these formulas (means 32-47 micrograms/mL), the typical
daily volume of milk consumed, and average bodyweight, a 4-month-old
infant
fed soy formula would be exposed to 28-47 per day, or about 4.5-8.0 mg/kg
bodyweight per day, of total isoflavones. Mean (SD) plasma concentrations
of
genistein and daidzein in the seven infants fed soy-based formulas were
684
(443) ng/mL and 295 (60) ng/mL, respectively, which was significantly
greater (p < 0.05) than in the infants fed either cow-milk formulas (3.2
[0.7] and 2.1 [0.3] ng/mL), or human breast-milk (2.8 [0.7] and 1.4 [0.1]
ng/mL), and an order of magnitude higher per bodyweight than typical
plasma
concentrations of adults consuming soy foods. INTERPRETATION: The daily
exposure of infants to isoflavones in soy infant-formulas is 6-11 fold
higher on a bodyweight basis than the dose that has hormonal effects in
adults consuming soy foods. Circulating concentrations of isoflavones in
the
seven infants fed soy-based formula were 13000-22000 times higher than
plasma oestradiol concentrations in early life, and may be sufficient to
exert biological effects, whereas the contribution of isoflavones from
breast-milk and cow-milk is negligible.
Comment in: Lancet 1997 Sep 13; 350(9080):815-6
--Chris Hafner-Eaton, PhD, MPH, CHES, IBCLC [log in to unmask]
€€€INFANT CUISINE AND MOTHER CARE: LACTATION CONSULTING & PERINATAL
CARE€€€
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