Allergy is a hypersensitivity reaction initiated
by immunological mechanisms to substances that, in the majority of
people, cause no symptoms and clinically manifests as atopic eczema,
rhino-sinusitis, conjunctivitis or asthma. During the current era, there
has been an increase in prevalence of allergic disorders which is
attributed to changes in environmental-host factors. The so-called
"hygiene hypothesis" (Microbial deprivation syndrome) suggests that a
lack of exposure to microbial stimulus early in childhood is a major
factor involved in this trend. This provides a rationale for using
probiotics to modify the gut microbial flora, thereby altering the
immune response of the host (from Th2 to Th1) and reducing the symptoms
of allergy.
There is a recent surge in studies on the effect of
probiotics on the clinical symptoms and medication use among children
with established allergic diseases. Probiotics are products or
preparations containing viable numbers of microorganisms that are able
to modify the host’s microflora, thereby producing beneficial health
effects [1]. Lactobacilli are considered to induce reactions involving
Th1 cells and to improve allergic diseases. In the article published in
this issue of the journal [2], it has been concluded that
Lactobacillus salivarius treatment reduces rhinitis symptoms and
drug usage in children with allergic rhinitis. A meta-analysis of the
published randomized controlled trials studying the effect of probiotics
on allergic disorders revealed nine of the 12 RCTs showing an
improvement due to the use of probiotics. All the RCTs that studied
perennial allergic rhinitis showed lower symptom scoring and medication
use with the use of probiotics compared with placebo [3]. There is also
evidence from animal models and in vitro studies that gut micro
biota modulate immune programming, promote oral tolerance, and are
important inhibiting the development of the allergic phenotype.
However, the therapeutic effect of prebiotics or
probiotics may be reduced once colonization and the allergic phenotype
are established compared with treatment at younger ages when there is
greater plasticity. It has also been studied that probiotics have some
beneficial role in reducing the allergic disorders in the children when
given to their mother during the third trimester of pregnancy and also
in the newborn period before colonization occurs [4]. After a decade of
research in the field of allergy and probiotics, no general
recommendations for their use can be given [5]. There are a few trials,
with positive and negative both results and only a limited number of
strains have demonstrated benefits in the area of preventing allergic
diseases. Hence, this hypothesis needs to be studied in detail before
drawing any necessary conclusions.
1. Havenaar R, Huis in’t Veld JHJ. Probiotics: A
General View. The Lactic Acid Bacteria. In: Wood BJB. The Lactic
Acid Bacteria in Health and Disease. London: Elsevier Applied Science;
1992.p.151-71.
2. Teng-yi lin, Chia-Jung Chen, Li-Kuang Chen,
Shu-Hui Wen, Rong-Hwa Jan. A randomized prospective double blind
controlled trial of the effect of probiotics on allergic rhinitis
confined to df, dp or dust-sensitive children. Indian
Pediatr.2012;50:209-13.
3. Vliagoftis H, Kouranos VD, Betsi GI, Falagas ME.
Probiotics for the treatment of allergic rhinitis and asthma: systematic
review of randomized controlled trials. Ann Allergy Asthma Immunol.
2008;101:570-9.
4. Peucchi C, Chatenoud L, Turati F, Galeone C, Moja
L, Bach JF, La Vecchia C. Probiotics supplementation during pregnancy or
infancy for the prevention of atopic dermatitis: a meta-analysis.
Epidemiology. 2012;23: 402-14.
5. Kalliomäki M, Antoine JM, Herz U, Rijkers GT,
Wells JM, Mercenier A. Guidance for substantiating the evidence for
beneficial effects of probiotics: prevention and management of allergic
diseases by probiotics. J Nutr. 2010:140:713S-721S.
