Measurement / residue studycited by the Tayebat archiveabstract only checked★ key study A-LEG-07 in-depth review

Soy formula and infant plant-oestrogen levels

Exposure of infants to phyto-oestrogens from soy-based infant formula.

Overview

Setchell KD et al.. Lancet 1997 · PMID 9217716 · DOI 10.1016/S0140-6736(96)09480-9

Soy-fed infants had isoflavone blood levels hundreds of times higher than other infants.

Does the study support the specific claim? Partly · Methodological quality: moderate

Study explained simply

What did the researchers want to find out?: Measure infant exposure
How was the study done?: Formula analysis and blood levels
How many people, animals or samples were studied?: 21 infants (7 soy formula, 7 cow-milk formula, 7 breast-fed)
What was actually found?: Very high isoflavone levels
How large was the observed effect?: 684 vs ~3 ng/mL genistein
What do the results mean in everyday life?: Soy formula only on indication.
What are the study's limitations?: Tiny sample; no health outcomes
What does it say about Elawady's specific claim?: Supports exposure, not harm
Do the results apply to Germany and Europe?: Moderate
What can explicitly not be concluded from this study?: Cannot show clinical harm.

Authors: Setchell KD, Zimmer-Nechemias L, Cai J, Heubi JE
Journal: Lancet
Year: 1997
Identifier: PMID 9217716 DOI 10.1016/S0140-6736(96)09480-9
Verification: verified – PubMed E-utilities efetch, 2026-10-25
Retracted: no
Corrections: none
Extent checked: abstract only
Conflicts of interest and funding: Funding: NCRR NIH (per PubMed record); COI not stated

Extent of infant isoflavone exposure from soy formula.

Study design: Measurement / residue study – Formula composition analysis plus cross-sectional comparison of infant plasma levels
Population: 4-month-old infants
Country: USA (inferred from funding; not stated in abstract)
Period: Not stated
Sample size: 25 formula samples; 21 infants (7 soy, 7 cow-milk formula, 7 breast-fed)
Inclusion and exclusion criteria: Exclusive feeding type

Results: Exposure 4.5-8.0 mg/kg/day total isoflavones; plasma genistein 684 (SD 443) ng/mL and daidzein 295 (60) ng/mL vs 3.2 and 2.1 (cow-milk) and 2.8 and 1.4 (breast milk); 6-11 fold higher per bodyweight than hormonally active adult dose; 13,000-22,000 times plasma oestradiol.
Absolute risks: not reported
Authors' conclusion: Concentrations may be sufficient to exert biological effects.

Exposure ratios, not risk estimates.

Exposure basis of C-LEG-10.

Strom 2001 (no major adult outcome differences).

Moderate.

Correct exposure data; no outcome evidence.

Multidimensional assessment
Multidimensional assessment
Authenticity of the source	verified
Methodological quality	moderate
Risk of bias	some concerns
Precision of results	low
Directness	indirect
Reproducibility	replicated
Consistency with the overall evidence	consistent
Regional transferability	moderate
Adequacy of the interpretation (by the archive)	essentially correct but incomplete

Long-term clinical significance.

Note: according to the archive, the studies were compiled by the archive operators. Whether Dr. Elawady himself cited this study is not established.

What the archive says about the study: Soy-formula infants receive isoflavone doses 6-11 fold higher than hormonally active adult doses.
A. What was actually studied?: Isoflavone exposure in infants.
B. What did the authors find?: As above.
C. What conclusions do the authors themselves draw?: 'May be sufficient to exert biological effects'.
D. What does the archive derive from it?: Presented as showing hormonally concerning levels.
E. Is this derivation scientifically justified?: Exposure correctly reported; 'may' is turned into concern without outcome data; irrelevant to non-soy legumes.
Adequacy of the interpretation (by the archive): essentially correct but incomplete