The soy isoflavone genistein may inhibit intestinal cell growth in babies, say US researchers, who have carried out tests on newborn piglets. Their findings could have a significant impact on makers of soy formula, consumed by around 25 per cent of formula-fed babies in the US. Researchers found that in newborn piglets fed a formula supplemented with genistein at the level found in soy formula, the number of proliferating cells in the intestine was 50 per cent lower than in piglets fed cow’s milk formula alone. The team from the University of Illinois point out that newborn piglets are a good model for human infants as they have a similar metabolism and physiology. Concentrations of genistein in the piglets’ blood were similar to those of babies fed soy formula, so these data may be applicable to human infants, said Professor Sharon Donovan, who carried out the research released on Pediatric Research online on 7 December. She explaind that although babies on soy formula appear to grow normally, these formulas contain very high concentrations of genistein, from 32 to 45 milligrams, which is higher than the amount found to affect menstrual cycles in women.
