Soy Foods
Soy foods as functional foods: meta-analysis of soy protein and LDL cholesterol, the FDA 25 g claim, isoflavones for menopause, and soy versus supplements.
Content last updated . This page has not been medically reviewed.
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Overview
Soy foods include tofu, soy milk, edamame and tempeh. Soy contains protein and isoflavones, which are phytoestrogens.What the research shows
| Question | Finding | Evidence type |
|---|---|---|
| LDL cholesterol | A meta-analysis of 46 trials identified by the FDA found soy protein (median 25 g a day for 6 weeks) lowered LDL by 4.76 mg/dL (95% CI -6.71 to -2.80), roughly 3 to 4%. [1] Another meta-analysis examined soy protein and serum lipoproteins. [2] | Trials |
| FDA label claim | A health claim says diets low in saturated fat and cholesterol that include 25 g or more of soy protein a day "may" or "might" reduce the risk of heart disease. [3] | Labeling rule |
| Menopause symptoms | A 2025 meta-analysis of 12 studies found isoflavones improved menopausal symptoms (7 studies, 533 participants, Hedges' g -0.25). [4] | Trials; small effect |
| Breast cancer | A meta-analysis of prospective studies found an inverse association between isoflavone intake and breast cancer occurrence. [5] | Observational |
Foods vs supplements
These results are for soy protein and isoflavones in trials; they do not tell you what a soy isoflavone capsule does, and isoflavone supplements are a separate topic. Proper evidence comparing whole soy foods with supplements was not found.Safety and individual considerations
- Soy is a major allergen.
- If you have a hormone-sensitive condition or take thyroid medicine, ask your clinician about soy amounts; we did not find a source we could read to quote.
Related
Tempeh · Miso · Nutrients and compoundsFrequently asked questions
Does soy lower cholesterol?
A meta-analysis found about a 4.76 mg/dL reduction in LDL with soy protein, around 3 to 4%. [1]
References
- Blanco Mejia S et al. A Meta-Analysis of 46 Studies Identified by the FDA Demonstrates that Soy Protein Decreases Circulating LDL and Total Cholesterol Concentrations in Adults. J Nutr 2019. PMID 31006811.
- Anderson JW et al. Soy protein effects on serum lipoproteins: a quality assessment and meta-analysis of randomized, controlled studies. J Am Coll Nutr 2011. PMID 21730216.
- U.S. Government. 21 CFR 101.82: Health claims: soy protein and risk of coronary heart disease. Electronic Code of Federal Regulations, read 2026-10-22.
- Luan H et al. Effects of soy isoflavones on menopausal symptoms in perimenopausal women: a systematic review and meta-analysis. PeerJ 2025. PMID 40718787.
- Boutas I et al. Soy Isoflavones and Breast Cancer Risk: A Meta-analysis. In Vivo 2022. PMID 35241506.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.