The debate rages on and on for us over at the CAN (Children’s Allergy Network) Facebook group. Soya, is it good for our children? Will it have long term effects on their reproductive health?
The main problems are 1) there are conflicting messages from the NHS (website and health professionals) on the topic and 2) we use the internet so much for personal research purposes do we really check how up to date the information is before we take the advice given.
Our dieticians are telling some of us that it is OK and others that is not and we can only assume that some are better read on the subject than others (for the record our dietician is pro-soya).
The online information from the NHS is in the form of a leaflet on breast cancer (for adults) and here (advice for soya consumption in pregnancy). The leaflet was written in 2011 and does state that there is no definitive link between phytoestrogens from soya and breast cancer, but there was shown to be a possibility of a link from tests on cells in a laboratory. Be wary of jumping to conclusions on these type of studies as individual cells in labs do not always work the same as cells in your body which interact with multiple systems.
The second NHS page is of interest as it mentions soya baby formula. It basically doesn’t recommend unless your child will not tolerate other hydrolysed formula. It states that it is ‘likely’ to affect your child’s reproductive development, but does not say what research it bases this conclusion on. It doesn’t say when the original article was written, only that it was reviewed in 2013.
If you are interested in reading more about phytoestrogens, this is a good article (with references) from 2010 from patient.co.uk.
Finally after a bit more digging I came across NHS Inform (who I have never heard of before today), who advise us that COT (Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment) advised in 2003 that there may be a potential risk for infants fed on soya based formula. This makes this advice 10 years old and the article in the website itself is 2 years old, however it does give us more of the rationale for the current NHS advice.
So to America, their advice should be more up to date as they really are leaders in the field. In the US, the National Institute of Environmental Health Sciences declared in 2010 that soya infant formula was only of minimal concern with regards to adverse effects – read the whole document here.
And finally, popular with allergy parents, the Mayo Clinic, their article on soya consumption in children was updated as recently as 2012. They don’t reference any particular article, but do seem to be stating that at the moment we don’t have proof of an effect one way or another.
So what do we know: ‘may’, ‘could’, ‘minimal effect’ have all been used in respect of impact on reproductive health over the last few years. There seems to be reason for this debate to continue until better studies are undertaken, there are no conclusions here, but here are some of the most recent accessible articles on the subject.
Recent articles addressing soya for babies
1. Developmental status of 1 year old infants fed breast milk, cows milk formula or soy formula, June 2012
Study of 391 babies showed no developmental difference between babies fed on soya compared to other formula.
2. Early life soy exposure and age at menarche, 2011 (not as up to date as I would like, but a large study and too interesting to leave out).
Study of 2920 girls, really interesting, needs to be read through, compares early soya fed babies (before 4 months) and late fed soya (after 4 months) as well as children on normal formula.
3. Early exposure to soy isoflavones and effects on reproductive health: a review of human and animal studies, 2010
This seems to be the review that so many guidelines are based on, note all the scary side effects are from animal studies and not humans and they often don’t compare well (also delivery of isoflavones in the animals were sub cutaneous not oral).
4. Phytoestrogen content of foods of animal origin: dairy products, eggs, meat, fish and seafood, 2013
A reminder that all food contains phytoestrogens.