Researchers from the Netherlands have reported in the March issue of Allergy that supplementation with a mixture of short-chain galacto-oligosaccharides (GOS) and long-chain fructo-oligosaccharides (FOS) appears to decrease total levels of the allergic antibody IgE, as well as IgG subclasses 1, 2 & 3, while increase levels of the "blocking" antibody IgG4.
These oligosaccharides are known as "prebiotics", and they supply a nutrition source for the "good bacteria" (probiotics) that colonize our gastrointestinal tracts shortly after birth.
The microbial environment in the gut may be an important factor in the risk of developing allergic disease, such as atopic dermatitis (eczema).
The interesting thing about this study is that it demonstrated that despite the overall decrease in antibody levels, the immune response to vaccinations was preserved. This is important, because antibodies are essential to protecting us from infection, and a decrease in allergic risk at the expense of adequate immunity against infection would not be not especially helpful.
So, should we be rushing to supplement the diets of our infants with prebiotics to skew the developing immune systems of our kiddos towards a less-allergic phenotype?
Breastmilk has plenty of oligosaccharides, and there's not evidence that infant formula supplemented with oligosaccharides is any better at preventing allergy than breastfeeding.
So when worried expectant moms come to me and ask what they can do to decease allergy and asthma risk in their soon-to-be-born babies, this is what I recommend:
1) Don't worry too much about what you eat during pregnancy- sensitization does not appear to occur in utero.
2) Actually, don't worry too much during pregnancy in general! (see my previous post about stress during pregnancy increasing asthma risk)
2) Try to have a vaginal delivery, so that your baby's gut can be colonized with beneficial bacteria as soon as possible.
2) Breastfeed!!! (but don't delay the introduction of solids beyond 6 months)
3) If you must transition to formula, consider a partially hydrosylated formula with prebiotics.
The evidence is emerging and recommendations continue to evolve- this is definitely an area of allergy which I will continue to follow closely...