Soy phyto-oestrogens reach hormonally concerning levels in infants fed soy formula (6-11 fold the hormonally active adult dose; plasma isoflavones 13,000-22,000 times oestradiol).
Original statement
No Arabic original wording available.
Translation
Soy phyto-oestrogens reach hormonally concerning levels in infants fed soy formula (6-11 fold the hormonally active adult dose; plasma isoflavones 13,000-22,000 times oestradiol).
Origin
- Source status
- Archive editors
- Attribution
- Archive editors
- Origin
- https://eltayebat.com/rule/legumes/
- Attribution uncertainty
- Archive editorial text and study selection written by the archive operators, not necessarily by Elawady.
- Claimed mechanism
Isoflavones (genistein, daidzein) bind oestrogen receptors; goitrogenic effects with iodine deficiency.
- Claimed health effect
Possible hormonal/developmental effects in infants.
- Population concerned
Infants fed soy-based formula
- Geographic restriction by Elawady
none found
Scientific assessment
Potentially true – Some evidence points in favour of the statement, but it is not sufficient for a clear judgement.
Certainty of evidence: low – Further research is likely to change the assessment considerably.
1. What was claimed?
Soy formula exposes infants to hormonally relevant isoflavone levels.
2. What is demonstrably correct?
The exposure figures are correctly cited from Setchell 1997; altered vaginal-cell DNA methylation was observed in soy-fed girls (Harlid 2017).
3. What is wrong or exaggerated?
Exposure does not equal harm. The retrospective cohort by Strom 2001 found no significant differences in general or reproductive health in young adulthood, except slightly longer menstrual bleeding (0.37 days) and more menstrual discomfort. The finding concerns infant soy formula, not legumes eaten by children or adults, and not fava beans or lentils.
4. What remains unclear?
Long-term effects of the epigenetic and subtle tissue changes are unknown.
5. Which studies support it?
Setchell 1997 (exposure); Doerge & Sheehan 2002 (mechanistic, animal). Harlid 2017 (A-LEG-09) is weak and indirect: it measured no isoflavone levels, its discovery scan (10 infants) was uncorrected and age-imbalanced, the overall methylation trajectory did not differ (p=0.25), and the authors state the data are not a clear contraindication to soy formula.
6. Which studies contradict it?
Strom 2001.
7. What applies to Germany and Europe?
European paediatric societies restrict soy formula to specific indications (not verified in this review).
8. What is known about Egypt?
Not specific.
9. What practical conclusion is appropriate?
Soy formula should not be used without an indication in young infants; this does not support avoiding legumes in general.
Assessment details
- Rationale for certainty of evidence
Exposure data are solid (Setchell 1997, n=7 per group); epigenetic changes in a small study (Harlid 2017); but long-term follow-up (Strom 2001, 248 soy vs 563 cow-milk formula) found no differences in >30 outcomes except slightly longer menstrual bleeding and more discomfort. Clinical significance remains uncertain.
- Source quality
Archive cites exposure and mechanistic studies; omits the reassuring long-term cohort.
- Regional transferability
Soy formula is used for specific indications in Europe; not directly relevant to adult consumption of fava beans or lentils (which are not soy).
- Individual exceptions
Infants with cow-milk protein allergy may receive soy formula only on medical advice.
- Regional scope of the claim
- not specified
- Last reviewed
- 25 October 2026 provisional
In plain language
Babies fed soy-based formula take in large amounts of plant oestrogens relative to their body weight, and some subtle biological changes have been measured. A long-term study of adults who were fed soy formula as babies found no major health differences, apart from slightly longer periods in women. The question concerns infant formula only and says nothing about fava beans or lentils.
Studies on this claim
Studies supporting the claim (1)
-
Soy formula and infant plant-oestrogen levels
Setchell KD et al.. Lancet 1997 · PMID 9217716 · DOI 10.1016/S0140-6736(96)09480-9Measurement / residue studycited by the Tayebat archiveabstract only checked★ key studySoy-fed infants had isoflavone blood levels hundreds of times higher than other infants.
Does the study support the specific claim? Partly · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
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.
No study in this group is marked as key.
Studies contradicting or limiting the claim (1)
-
Adults fed soy formula as babies
Strom BL et al.. JAMA 2001 · PMID 11497534 · DOI 10.1001/jama.286.7.807Cohort studyindependent cross-checkabstract only checked★ key studyNo major health differences in young adulthood; slightly longer menstrual bleeding in women.
Does the study support the specific claim? No · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Long-term soy formula effects
- How was the study done?
Retrospective cohort
- How many people, animals or samples were studied?
811 adults
- What was actually found?
Mostly no differences
- How large was the observed effect?
+0.37 days bleeding
- What do the results mean in everyday life?
Reassuring for soy formula.
- What are the study's limitations?
Self-report
- What does it say about Elawady's specific claim?
Limits concern
- Do the results apply to Germany and Europe?
Moderate
- What can explicitly not be concluded from this study?
Cannot exclude subtle effects.
No study in this group is marked as key.
Studies with mixed or unclear results (2)
-
Soy and the thyroid
Doerge DR, Sheehan DM. Environ Health Perspect 2002 · PMID 12060828 · DOI 10.1289/ehp.02110s3349Narrative reviewcited by the Tayebat archiveabstract only checkedSoy compounds inhibit a thyroid enzyme in the lab, but thyroid function in rats stayed normal; iodine deficiency is key.
Does the study support the specific claim? Unclear · Methodological quality: low · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Review soy toxicity
- How was the study done?
Narrative review
- How many people, animals or samples were studied?
Animal/in-vitro
- What was actually found?
Enzyme inhibition, no overt thyroid disease
- How large was the observed effect?
Up to 80% TPO reduction (rat)
- What do the results mean in everyday life?
Iodine sufficiency matters.
- What are the study's limitations?
Animal data
- What does it say about Elawady's specific claim?
Indirect
- Do the results apply to Germany and Europe?
Low
- What can explicitly not be concluded from this study?
Cannot show human harm.
-
Soy formula and gene marks in baby girls
Harlid S et al.. Environ Health Perspect 2017 · PMID 27539829 · DOI 10.1289/EHP428Cohort studycited by the Tayebat archivefull text checkedSmall study found gene-methylation differences in soy-fed girls; health meaning unknown.
Does the study support the specific claim? Partly · Methodological quality: low · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Test epigenetic effects
- How was the study done?
Cohort + mouse
- How many people, animals or samples were studied?
50 girls
- What was actually found?
Methylation differences in one gene
- How large was the observed effect?
Not applicable
- What do the results mean in everyday life?
Biological effect possible.
- What are the study's limitations?
Small; no outcomes
- What does it say about Elawady's specific claim?
Weak support
- Do the results apply to Germany and Europe?
Moderate
- What can explicitly not be concluded from this study?
Cannot show disease.
No study in this group is marked as key.
Regional context
Germany / EU
European paediatric societies restrict soy formula to specific indications (not verified in this review).
Egypt
Not specific.
What applies in my country?
General scientific assessment
Potentially true High infant exposure is documented; clinical harm is uncertain, and it is irrelevant to other legumes.
The following areas of food safety are relevant to this statement:
- Pesticides and pesticide residues
- Contaminants (heavy metals, PFAS, PCBs, dioxins, nitrate)
- Mycotoxins (mould toxins)
Legumes and nuts
Choose a country to see the checked information for it.
Limits: legal rules describe what is allowed, not what every single food contains. Measurement data come from samples and are meaningful only together with their method details.
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References
- Exposure of infants to phyto-oestrogens from soy-based infant formula.. Setchell KD et al.. Lancet 1997 · PMID 9217716 · DOI 10.1016/S0140-6736(96)09480-9
- Exposure to soy-based formula in infancy and endocrinological and reproductive outcomes in young adulthood.. Strom BL et al.. JAMA 2001 · PMID 11497534 · DOI 10.1001/jama.286.7.807
- Goitrogenic and estrogenic activity of soy isoflavones.. Doerge DR, Sheehan DM. Environ Health Perspect 2002 · PMID 12060828 · DOI 10.1289/ehp.02110s3349
- Soy Formula and Epigenetic Modifications: Analysis of Vaginal Epithelial Cells from Infant Girls in the IFED Study.. Harlid S et al.. Environ Health Perspect 2017 · PMID 27539829 · DOI 10.1289/EHP428