Probiotics: Myths or facts about their role in allergy prevention

Background. The hygiene hypothesis proposed by Strachan in the 1980s clearly emphasized the role of microorganisms in atopy prevention. Objectives. The study objective was to assess the preventive role of probiotics in patients with allergic rhinitis, bronchial asthma, atopic dermatitis, and/or food allergy. Material and methods. The methods used in the study were the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaires for 6-7- and 13-14-year-olds and the European Community Respiratory Health Survey II (ECRHS II) questionnaire targeted for the 20-44 age group. The study was conducted as part of the cross-sectional Epidemiology of Allergic Diseases in Poland study conducted in 9 Polish regions (8 urban: Warszawa, Lublin, Bialystok, Gdansk, Poznan, Wroclaw, Katowice, Krakow, and the rural regions of Zamojski and Krasnostawski counties). The study material was a group of patients diagnosed with food allergy (n = 407), atopic dermatitis (n = 311), allergic rhinitis (n = 1.353), bronchial asthma (n = 505), and healthy volunteers (n = 2,403). Results. Genetic factors play an important role in the allergy development. A family history positive for chronic skin disorders increased the risk of atopic dermatitis and food allergies (OR = 1.456, CI = 1.14-1.85, p = 0.002; and OR = 1.378, CI = 1.05-1.81, p = 0.02, respectively). The consumption of products containing live bacterial cultures showed no preventive effects in any of the evaluated disorders in early childhood. Conversely, over the age of 14 years, probiotic formulations exhibit health-promoting effects and may lower the risk of allergic diseases. Conclusions. The use of probiotics in the Polish population showed no protective effect in the first years of life. The changes in dietary habits introduced during late adolescence demonstrated significantly greater preventive effects of live bacterial cultures against the development of allergic diseases.