Soy Protects Infants from Common Virus

by Kyle Bradley 

URBANA, Ill.-Soy-based infant formula (SBIF) decreased rotavirus (RV) infection incidence in vitro via the isoflavone genistin, according to a study in The Journal of Nutrition (Sept. 2007;137:2068-2073). All isoflavones found in SBIF concentrations were tested individually and as a mixture. Virus infectivity was assessed in MA-104 cells using a focus forming unit assay.

Genistin and the mixture significantly reduced RV infectivity by 33 to 62 percent and 66 to 74 percent, respectively, compared with the control and across a wide range of RV concentrations. The combo lost its anti-RV activity when tested without genistin, suggesting genistin was the biologically active isoflavone in this instance. Isoflavones decreased RV infectivity by modulating virion attachment to the host cells and by modulating a postbinding step; they did not alter RV triple-layered structure, and genistin did not act through inhibition of protein tyrosine kinases and topoisomerase II or by mimicking the effect of estrogens. Researchers suggested soy isoflavones represent a novel approach to reducing the severity of RV infections in infants and animals.