Health committee warns of potential dangers of soyaBMJ 2005; 331 doi: http://dx.doi.org/10.1136/bmj.331.7511.254-a (Published 28 July 2005) Cite this as: BMJ 2005;331:254
Israeli manufacturers of soya products were rattled by the recommendation issued by the country's health ministry that consumption of soya products be limited in young children and avoided, if possible, in infants. After a year's work, a committee of experts also advised that adults who eat soya products do so in moderation, pending authoritative future studies.
Although research showing possible harm—a higher risk of cancer, male infertility, or other problems—from soya is based on animal or retrospective human studies, the committee of 13 issued recommendations based on the precautionary principle. Soya contains phytoestrogens that may have some of the effects of the human hormone if consumed in large quantities.
Soya consumption is high in Israel, and use of soya based baby formula is among the world's highest per capita. Nevertheless, the ministry decided not to prohibit the sale of soya based formula without a doctor's prescription, which is already required in New Zealand and Australia.
Widespread soya use in Israel is due to a number of reasons, most prominently kosher food practices. Jewish law and tradition forbid the mixing of milk and meat products, dishes, and cutlery, and after eating meat individuals must wait some six hours before ingesting dairy foods.
Although this interval is not required of babies, many ultraorthodox mothers observe it anyway, and those who do not breastfeed prefer soya based rather than cow's milk formulas so bottles are not on the table during meat meals. The actual need for soya based formula due to allergy to cow's milk based formula is negligible.
Since soya provides cheaper protein than meat, it is widely served in various forms, especially in day care centres that are spared from using separate dishes and cutlery. Soya burgers made from reconstituted flakes and other forms, many of them developed by Israeli companies, as well as tofu and misu, are popular among health conscious people.
“We don't know the long term effects on health of large amounts, so we are urging moderation,” said Dorit Nitzan Kaluski, director of the health ministry's food and nutrition service who was a committee member. “We want to be careful. And while it is easy to identify soya products, there is much more soya added to foods such as breads, cakes, cookies, and crackers.”
Paediatricians will monitor the thyroxine concentrations in infants and toddlers who have hypothyroidism who drink soya based formula or soya foods. And women with breast cancer or a high risk of it will be advised to consult their doctors about soya in their diets.
Dr Nitzan Kaluski said that to avoid pressure from soya food firms, the committee did not inform them in advance, but within a day of the report's release, she received at least one lawyer's letter and numerous requests for information. She expects lawsuits are on the way.