When your baby has food sensitivities, avoiding dairy and soy is often recommended because these are the most common food issues with food sensitive bread or bottle fed babies.
When avoiding soy, it is the soy protein that is causing the issues here. But soy in foods can take different forms, and be found in the most surprising places.
If soy is present in a food/drink, then the packaging needs to carry this information- often found in the allergen alert.
Are all ' contain soy' statements equal?
'CONTAINS SOY'
Next time you check a food or medication to see if it contains soy, see what sort of soy a 'Contains soy' statement is referring to. Is is soy beans? Soy oil? Soy lecithin?
What type of soy it is may impact on your decision to consume the food or drink.
SOY BEANS & SOY ALLERGY or INTOLERANCE
The foods that contain significant amounts of soy protein include all the well known soy foods: soy milk, soy beans, tofu, tempeh, miso, soy sauce, edamame, soy albumin (a soy protein) and textured soy protein foods (extra high in soy protein!).
These foods or foods containing these ingredients are to be avoided, and unquestionably the 'Contains Soy' statement supports this decision.
SOY FLOUR & SOY ALLERGY or INTOLERANCE
Small amounts of soy such as soy flour are often best avoided if possible, and these small sources of soy do contain soy protein (or soy protein isolate), and for many (not all) sensitive babies is often enough to cause issues.
In the same way, cold pressed soy oil is best excluded. Cold-pressed soy bean oil has a protein profile similar to soybean flour, but is not typically used as an ingredient in foods. See below re: normal soy oil (not cold-pressed).
Soy fibre may have differing amounts of protein deepening on its extraction process, and best viewed as a 'to be excluded' soy containing soy protein.
Again, worthy of the 'Contains Soy' allergy statement.
SOY LECITHIN & SOY ALLERGY or INTOLERANCE
Soy lecithin is made from the fat components of the soy bean. The protein is mostly removed during the purification process.
Soy lecithin does contain trace (very small) levels of soy proteins and these have been found to include soy allergens. However, soy lecithin does not contain sufficient soy protein residues to provoke allergic reactions in the majority of soy-allergic people and babies.
Many allergists do not even advise their soybean-allergic patients to avoid soybean lecithin when it is included as an ingredient on food products. Research indicates that most individuals allergic to soy can safely eat soy lecithin and soybean oil.
In the same way, soy antioxidants and soy oil, with the exception of cold pressed soy oil, are also found to be well tolerated by babies, children and people with soy allergies.
In addition, these soy components: soy lecithin, soy oil and soy antioxidants, when added to foods are added in very small amounts.
Compare this again to the diluting effects of breast milk, and the propensity of soy in these ingredients is very low.
Like all situations, there are always a subset of babies or children or adults who are hypersentivie. It is important that recommendations for all breast fed soy allergic/intolerant babies are not based on the small number of babies who are hypersensitive, just like is is not useful to base Coeliac Disease or Diabetes recommendations for those who are extremely more sensitive than the bulk of people.
Stepping into the next level restriction can be considered if symptoms not able to be managed, but not recommended in the first instance.
A ' Contains Soy' allergen statement when the soy is soy lecithin, soy antioxidants or soy oil does nto mean that the food or medication has to be avoided. Personal choice comes into play here.
SOY DERIVED FOOD INGREDIENTS
The next level down in terms of imperceptible amounts of soy are food or processing components derived from soy. Labelling laws doe not require soy labelling here as any ingredients derived from soy has changed so much that it does not classify as a soy ingredient.
Consider this a step down again from the above.
THE SOY WRAP
This information can be used as a guide so you can make your own personal choice about which foods to exclude or not when pursuing a soy free diet for your breast fed baby with soy allergy or intolerance.
My personal interest is sharing evidence based information - especially as this area can be fraught with lots of different information sharing and opinions. So you can be empowered in making deciding your own best choice in caring for your baby.
Frances Walker
Dietitian specialising in Food intolerances in breast fed babies
REFERENCES
1. Soy allergy | Healthy Eating Advisory Service. Heas.health.vic.gov.au. https://heas.health.vic.gov.au/early-childhood-services/allergy-and-intolerance/soy-allergy. Published 2022. Accessed June 6, 2022.
2. Soy. Foodstandards.gov.au. https://www.foodstandards.gov.au/consumer/foodallergies/allergies/Pages/Soy-.aspx. Published 2022. Accessed June 6, 2022.
3. https://www.foodstandards.gov.au/consumer/foodallergies/allergies/Pages/Soy-.aspx https://farrp.unl.edu/soy-lecithin. Published 2022. Accessed June 6, 2022.