Food allergies-do you need to be careful in pregnancy and breastfeeding?

It appears food allergy is becoming a more common problem, with some countries reporting a 50% increase in the rate of peanut allergy.  Overall it is estimated that around 5% of children develop food allergies most commonly to dairy products.  It is not well understood why allergy rates are on the rise.   Food allergies are more common with family histories of asthma and eczema.

Food allergy is distinct from food intolerance.  It is an immune-mediated response, usually to a protein in food and can cause a variety of reactions-both immediate and delayed.  The most serious of these events is anaphylaxis.  Food allergies tend to first present in early childhood and often resolve by the time the child is 5 (i.e. egg, milk) but some will be life-long (nuts, shellfish).

Given the growing size of the problem and possible implications, research has focused on ways of preventing future food allergy.  Studies have been performed, and continue to look at whether maternal avoidance of allergenic foods (nuts, seafood, egg, etc.) results in any reduced rate of allergy in the children of these women.

So far the answer is no.  There is no evidence that avoiding the more commonly allergenic foods (dairy, eggs, soy, gluten, shellfish, nuts) during pregnancy results in a lower risk of allergy in the children born of that pregnancy.  Some studies, in fact, report an increase in allergy rates when there is avoidance of these allergens in the maternal diet, though these results haven’t been consistent in all trials.

The second controversial area surrounds breastfeeding.  Again, there is some evidence that suggests that breastfeeding itself is associated with a reduced risk of allergy in children.  There is no evidence that a breastfeeding mother should avoid certain allergenic foods unless an allergy has been clinically diagnosed in her breastfed infant.  If the food allergy is diagnosed, she should continue to breastfeed but seek consultation with an experienced dietitian who can ensure her diet remains nutritionally adequate and well balanced and to ensure she has sufficient education regarding avoidance of the particular allergen/s.

The final area of interest surrounds introduction of solids for a child.  It is recommended that babies are exclusively breastfed for 4-6 months (guidelines vary depending on the country/organisation).  While in the past it has been recommended that the introduction of certain foods is delayed, the current evidence does not support delaying the introduction of any foods past six months, on the basis of allergy, once solids are commenced.

Dealing with food allergies can be worrisome and frustrating.  It is a complex area.  If you wish to discuss the topic further, please contact Dr Rahul Sen.