Nov. 19 - If a mother is unable to breastfeed her baby, she can fall back on infant formula from the drug store or supermarket. Products made from soybean protein and from cow's milk are on sale. Soybeans contain high concentrations of isoflavones. They should, therefore, only be given to infants over longer periods in exceptional, justified cases. Isoflavones are similar to the female hormone oestrogen; however, they have a far weaker effect. Furthermore, soybeans may also contain higher amounts of the plant component, phytate. Professor Dr. Dr. Andreas Hensel, President of the Federal Institute for Risk Assessment (BfR), comments, "Infant formula and follow-up formula made from soy protein should only be administered on medical grounds and then only under medical supervision."
Infant formula and follow-up formula based on cow’s milk protein or soy protein is for sale in the European Union. Soy formula should only be administered to infants over a longer period when this is necessary on medical grounds. This is because soy contains plant substances which may have hormone-like effects, the so-called phyto-oestrogens. The two main ones are the isoflavones genistein and daidzein. They have a similar chemical structure to the female hormone oestrogen. Compared to breast milk and to infant formula made from cow’s milk, isoflavones contain relatively high levels of soy protein. Hence far higher isoflavone concentrations were found in the blood of infants given soy than infants given cow’s milk formula or breast milk. Besides isoflavones, soy formula may also contain phytate. The natural plant component can influence the intake of minerals and trace elements.
The impact of the elevated intake of isoflavones on infants has not yet been fully elucidated. In animal experiments there were signs that elevated isoflavone intake affects the development of reproductive organs, the immune system and the thyroid gland. However, the results of animal experiments cannot simply be transposed to humans. For precautionary reasons BfR backs the recommendation of the Nutrition Committee of the German Society for Paediatric and Youth Medicine until further data become available. According to this recommendation, infant formula made from soy is no substitute for cow’s milk products. Babies who are not or not exclusively breastfed should only be given this formula in exceptional, concrete cases on doctor’s advice. Soy formula for infants is not intended for administration to healthy infants.
Possible medical reasons for giving soy formula to infants are, for instance, rare cases of congenital, hereditary lactase deficiency and the equally rare metabolic disease galactosaemia. Lactase intolerance - whether genetic or because of a temporary gastro-intestinal disorder - is not generally a reason for turning to lactase-free infant soy formula. In the case of infants with a cow’s milk allergy, too, the Committee does not recommend soy formula at the start of treatment. Where appropriate, special protein hydrolysates can be used. Soy protein itself can trigger allergic reactions and does not prevent allergic disorders.
If parents reject cow’s milk-based infant formula on ethical or religious grounds, soy formula is one alternative - but only after seeking medical advice.