Daidzein

Effects depend heavily on gut-microbiome capacity to produce equol (only ~30% of Westerners are equol producers). Benefits are modest even in responders.

A rough internal score reflecting quantity, quality, and consistency of human evidence. Not a clinical recommendation.

Equol producers show greater bone density and menopausal symptom relief from soy isoflavones. Meta-analyses show small reductions in LDL and hot flash frequency. EFSA rejected bone-health claims for lack of sufficient evidence.

• Mild phytoestrogenic activity for menopausal support
• May modestly reduce LDL cholesterol
• Equol metabolite has antioxidant properties

40–80 mg/day of soy isoflavones (providing ~20–40 mg daidzein). Effects depend on equol production capacity.

• GI discomfort
• Theoretical oestrogenic effects
• Thyroid concerns at very high doses

Phytoestrogenic activity—contraindicated in oestrogen-receptor-positive cancers (controversial). Thyroid function may be affected at very high doses.

Equol-producer status determines much of the response. Western populations are less likely to be equol producers than Asian populations.

• Mood28
• Longevity25