Are there really soya residues in chicken and eggs?

Michelle Berriedale-Johnson investigates after the FM newsboard received three calls within about soya residues within one week

Hot on the heels of Tracy Smith’s comment in the October Foods Matter about how her soya intolerant mother reacts to chickens and eggs which have been fed on soya, came a phone call from Jacquie Broadway (also highly soya intolerant) and the following from Julie Rogers:

I am very intolerant to soya in all its forms and worked out about the chicken and eggs a couple of years ago when I worked for a local egg producer. One of the perks of the job was a free tray of eggs each week but I couldn't understand why I was becoming so ill so often. After some investigation I found exactly what Tracy Smith described. Even the free-range chickens were fed a soya- based meal which, naturally enough, contaminated the eggs.
Now I only buy organic eggs and organic chicken, unless it is Marks & Spencer chicken from a supplier unique to M&S.
Problem solved. I find the eggs are okay whichever way I choose to cook them, yummy!

If we had had three comments within a week, how many more people were having chicken/egg related problems - and were they really right, that it was the soya feed that was causing the problem?

Is it possible?
First we asked Professor Jonathan Brostoff whether it was possible that sufficient allergenic material from the feed could remain in the chicken flesh or eggs to cause an allergic or intolerant reaction.

He said that it was an area in which very little work had been done and there was no clear scientific evidence either way but that if enough people with these sensitivities could be gathered together he would be interested to research it further.

So then we asked a public analyst - the laboratories which test food for microbiological contamination. Their molecular biologist thought it was ‘very unlikely’ that soya allergens from feed could migrate into the chicken flesh or eggs, but, being a cautious scientist, he was not prepared to say that it was impossible.

Do all chickens eat soya?
Both Jacquie Broadway and Julie Rogers seemed to be able to tolerate organic or M&S chickens so maybe they were not fed soya.

But they are...

We talked to all of the major supermarkets, all of whom confirmed that all of their chickens (and turkeys), including their organic ones, ate a feed which included soya protein.

Most seemed surprised - even peeved - that we should have even asked, and wanted to know how the chickens were meant to get their protein if they were not fed soya. We refrained from asking how our grandparents’ chickens got their protein...

Several of them also maintained that there was no way that any soya protein from the feed could migrate into the flesh of the birds into the eggs.

Meanwhile, Jacquie Broadways spoke to a whole selection of chicken farmers, large and small, organic and free range. While many of their birds (chickens, turkeys and even geese) led a carefree, and soya-free, outdoor existence for most of their lives, without exception all were given a booster feed before slaughter - and that booster feed always included some soya protein.

How much - and when
So while the scientists and the medic.s are still mulling on whether it is possible, the experience of our readers would suggest that soya-super-sensitives react to birds (and eggs) whose diet has contained relatively large amounts of soya over most of their lives, allergenic elements of which have, by some means, migrated into birds’ flesh and their eggs. But they do not react when the birds have only had a small amount of soya in their feed immediately prior to their demise.

So, more reports please to

First published in 2007

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