Soya allergy or intolerance is one of the most common food allergies in the UK being more common in families with atopic conditions. Infants and children with cow’s milk allergy should not use soya formula as an alternative, as up to two thirds of infants with non IgE mediated (delayed) reactions to cow’s milk also become sensitised to soya. General concerns, not associated with allergy, around the potential to promote oestrogen production have lead to recommendations to avoid soya for infants under 6 months of age.
What are the symptoms?
Symptoms of soya allergy range from mild to (very rarely) severe and involve atopic eczema, gastrointestinal symptoms such as diarrhoea, constipation and gastro-oesophageal reflux and rarely respiratory conditions like asthma. For infants and children with delayed reactions to soya, avoiding major sources of soya in the diet usually all that is necessary. The small amounts found as soya lecithin is usually well tolerated in non IgE (delayed reactions) soya intolerance.
Immediate symptoms of soya allergy
IgE mediated (immediate) reactions to eating soya are uncommon in the UK. Severe reactions are more common in young people who have existing allergies to other legumes such as peas and lentils; some may also be allergic to nuts. If you do suspect that your infant or child may have an immediate reaction to soya, it is best to get allergy tested. Ask your GP to refer you to the local Allergy Clinic.
What is soya and where is it found in the diet?
Soya is a legume and is often dried and ground into flour for use in baked products. The flour may also be used to make textured vegetable protein (TVP) used extensively in vegetarian products. Other uses include as a fermented product in tofu, miso and soya sauce. Fresh soya beans are usually referred to as Edamame beans, and are characteristically a deep green colour found in many Japanese dishes. Soya oil is widely available and used to make soya margarines and spreads. Soya lecithin is found in many products such as chocolate and functions as a stabiliser or emulsifier.