Last update Sept. 26, 2025

Soy

Likely Compatibility

Fairly safe. Mild or unlikely adverse effects. Compatible under certain circumstances. Follow-up recommended. Read Commentary.

Seeds, oil and extracts of this plant contain Lecithin and Isoflavones like Genistein, Glycitein and Daidzein. Lecithin is formed by phospholipids with hypolipidemic properties. Isoflavones are phytoestrogens which is a property that is being used for treatment of hyperlipidemias and disorders related to menopause.

Ingestion of soy derived products by nursing mothers may be a cause of increase concentration in the mother’s plasma, breast milk and infant’s urine (Franke 2006 &1998). The amount of soy foods does not significantly alter estrogen levels in nipple aspirate and serum. (Maskarinec 2011)

Despite of that soy has been consumed from ancient times by Asian population and could offer some benefit for the welfare, it may act as hormonal disruptor on the endocrine system (Jarrell 2012, Adgent 2012, Badger 2002), especially is the product contains Bisphenol A (Katchy 2014), hence, high exposition during infancy should be avoided.

Feeding infants soy milk, soy consumption, and lack of breastfeeding are risk factors for cryptorchidism (Barthold 2012) and central precocious puberty (Felício 2021), although other studies have found no link to cryptorchidism. (Andres 2015)

In some Asian populations, it is used as a galactagogue, although its effectiveness has not been proven. (Tan 2022)

Given the high phytoestrogen content (Zava 1998) and their possible endocrine effects, moderate consumption during breastfeeding is recommended.


See below the information of this related product:

  • Lecithin (Safe product and/or breastfeeding is the best option.)

Suggestions made at e-lactancia are done by APILAM team of health professionals, and are based on updated scientific publications. It is not intended to replace the relationship you have with your doctor but to compound it. The pharmaceutical industry contraindicates breastfeeding, mistakenly and without scientific reasons, in most of the drug data sheets.

Jose Maria Paricio, Founder & President of APILAM/e-Lactancia

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Other names

Soy is also known as


Soy in other languages or writings:

Group

Soy belongs to this group or family:

Tradenames

Main tradenames from several countries containing Soy in its composition:

List of 38 tradenames

References

  1. Tan ML, Foong SC, Foong WC, Ho JJ. Use of Galactagogues in a Multi-Ethnic Community in Southeast Asia: A Descriptive Study. Int J Womens Health. 2022 Sep 22;14:1395-1404. Abstract Full text (link to original source)
  2. Felício JS, de Alcântara AL, Janaú LC, de Moraes LV, de Oliveira MCNI, de Lemos MN, de Souza Neto NJK, Neto JFA, da Silva WM, de Souza ÍJA, Said NM, de Lemos GN, Vieira GM, Khayat AS, Dos Santos ÂKCR, de Queiroz NNM, de Sousa ACCB, Dos Santos MC, de Melo FTC, Piani PPF, Felício KM. Association of Soy and Exclusive Breastfeeding With Central Precocious Puberty: A Case-Control Study. Front Endocrinol (Lausanne). 2021 Jul 5;12:667029. Abstract Full text (link to original source)
  3. Andres A, Moore MB, Linam LE, Casey PH, Cleves MA, Badger TM. Compared with feeding infants breast milk or cow-milk formula, soy formula feeding does not affect subsequent reproductive organ size at 5 years of age. J Nutr. 2015 May;145(5):871-5. Abstract Full text (link to original source)
  4. Katchy A, Pinto C, Jonsson P, Nguyen-Vu T, Pandelova M, Riu A, Schramm KW, Samarov D, Gustafsson JÅ, Bondesson M, Williams C. Coexposure to phytoestrogens and bisphenol a mimics estrogenic effects in an additive manner. Toxicol Sci. 2014 Abstract
  5. Barthold JS, Hossain J, Olivant-Fisher A, Reilly A, Figueroa TE, Banihani A, Hagerty J, González R, Noh PH, Manson JM. Altered infant feeding patterns in boys with acquired nonsyndromic cryptorchidism. Birth Defects Res A Clin Mol Teratol. 2012 Abstract Full text (link to original source) Full text (in our servers)
  6. Adgent MA, Daniels JL, Rogan WJ, Adair L, Edwards LJ, Westreich D, Maisonet M, Marcus M. Early-life soy exposure and age at menarche. Paediatr Perinat Epidemiol. 2012 Abstract Full text (link to original source) Full text (in our servers)
  7. Jarrell J, Foster WG, Kinniburgh DW. Phytoestrogens in human pregnancy. Obstet Gynecol Int. 2012 Abstract Full text (link to original source) Full text (in our servers)
  8. Maskarinec G, Ollberding NJ, Conroy SM, Morimoto Y, Pagano IS, Franke AA, Gentzschein E, Stanczyk FZ. Estrogen levels in nipple aspirate fluid and serum during a randomized soy trial. Cancer Epidemiol Biomarkers Prev. 2011 Abstract Full text (link to original source) Full text (in our servers)
  9. Franke AA, Halm BM, Custer LJ, Tatsumura Y, Hebshi S. Isoflavones in breastfed infants after mothers consume soy. Am J Clin Nutr. 2006 Abstract Full text (link to original source) Full text (in our servers)
  10. Badger TM, Ronis MJ, Hakkak R, Rowlands JC, Korourian S. The health consequences of early soy consumption. J Nutr. 2002 Abstract Full text (link to original source) Full text (in our servers)
  11. Zava DT, Dollbaum CM, Blen M. Estrogen and progestin bioactivity of foods, herbs, and spices. Proc Soc Exp Biol Med. 1998 Abstract
  12. Franke AA, Custer LJ, Tanaka Y. Isoflavones in human breast milk and other biological fluids. Am J Clin Nutr. 1998 Abstract Full text (link to original source) Full text (in our servers)

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