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Panel Review of Soy Formula: No Reason for Concern - For Now

April 2006

A 14-member panel formed by the Center for the Evaluation of Risks to Human Reproduction convened March 15-17 in Alexandria, Va., under intense media scrutiny, to discuss and evaluate results of toxicity studies of genistein and soy formula.

Genistein is a phytoestrogen found in beans, particularly soybeans. Phytoestrogens are non-steroidal, estrogenic compounds that occur naturally in some plants. Genistein and a genistein-sugar complex called genistin are found in many food products, especially soy-based foods popular with vegetarians and including tofu, soy milk and soy infant formula.

Soy infant formula is used to supplement or replace human or cow milk. Soy formulas have been on the market for a number of years.

The panel, which consisted of independent scientists, reviewed existing scientific data on genistein and soy formula in three primary areas: human exposure, reproductive toxicity, and developmental toxicity. The panel identified data gaps on possible effects and suggested areas for more study.

Their conclusions were as follows:

  • Genistein: Even though there is a paucity of available human data on exposure to purified genistein, the panel expresses negligible concern for reproductive and developmental effects from exposure of adults in the general population; the panel expresses negligible concert for adverse effects in neonates and infants who may consume up to 0.01-0.08 mg/kg bw/day of genistein aglycone from soy formula.

  • Soy formula: There are insufficient human or experimental animal data available to permit a determination of the developmental or reproductive toxicity of soy infant formula.

  • The panel's final report will be posted on the CERHR website at and will be available in printed form in May. The CERHR, which is part of the National Toxicology Program, will seek public comments on the report, and will include those comments, along with their final report and an NTP brief in two monographs - one for soy formula and one for genistein.

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