Is it true that probiotics can prevent allergies in children?

In recent years, food allergies in infants and young children are no longer rare, with a prevalence of 0.83%-3.50%. Milk and egg allergies are the most common [1]. Soybeans, wheat, peanuts, fish, shrimp, nuts and other foods are also highly allergenic. Allergic symptoms are often gastrointestinal symptoms, such as intestinal cramps, vomiting, diarrhea, etc.; skin symptoms, including itching, erythema, dermatitis, eczema, etc. and respiratory symptoms such as acute rhinitis, conjunctivitis, etc. Although most food allergies can gradually heal themselves as children grow and develop, there are also reports that early infant food allergies may increase the incidence of other allergic diseases in children later in life [2], which should not be underestimated.

1. There is no history of allergies in the family, but the child got the "prize"!

Indeed, whether infants and young children have allergies depends largely on whether their parents have allergic diseases. If the parents do not have allergic diseases, the child still has a 10% chance of developing allergies. However, if one parent has a history of allergies, the child's incidence rate is as high as 20%-30%[3].

2. Probiotics prevent and treat allergies, a magical operation?

Probiotics refer to active microorganisms that are beneficial to the host after sufficient intake. They have the functions of promoting the digestion and absorption of nutrients, maintaining the balance of intestinal flora structure, and protecting the intestinal mucosal barrier. In recent years, there have been reports that probiotics may help prevent allergic diseases due to their anti-inflammatory effects, but this is controversial.

Many foreign guidelines on allergic diseases do not recommend taking probiotic preparations to prevent allergic diseases [4], but the World Allergy Organization (WAO) recommends that for children at high risk of allergies (parents with a history of allergies), probiotics can be considered to prevent allergic diseases; expectant mothers and breastfeeding mothers with a family history of allergies can also consider taking them. It should be noted that taking probiotic preparations may prevent skin allergic diseases such as eczema, but there is currently insufficient evidence to show that it is effective for other allergic diseases [5]. There are few reports in China on the use of probiotics to prevent allergic diseases.

3. How to choose from the large family of probiotics?

There are more than 20 kinds of commonly used probiotics in China, including yeast, bacillus, Clostridium butyricum, bifidobacterium, lactic acid bacteria, etc. Foreign studies on probiotics for infants and young children mostly use Lactobacillus rhamnosus, Bifidobacterium animalis, Saccharomyces boulardii, Bacillus subtilis, etc. There are reports abroad that Lactobacillus rhamnosus can be used to prevent or treat allergic diseases, but the level of evidence is low [6]. In fact, there is no sufficient evidence at home and abroad to show that probiotics of a specific genus can effectively prevent allergies. There is no clear recommendation on the dosage and duration of probiotic health products. How long should they be taken and what is the daily dose? Mothers do not need to worry too much about what kind of probiotics to buy and how to take them. Just follow the doctor's advice.

4. Are there any dangers of taking probiotics?

At present, the results of many studies at home and abroad have shown that there seems to be no harm in taking probiotics for people with normal immune function [4]. However, for babies who are allergic to milk protein, some probiotics may contain highly sensitive ingredients such as milk or wheat bran, which may cause or aggravate allergies. Therefore, when parents choose probiotic preparations, they should carefully read the product instructions and other information to be careful of counterproductive effects.

References:

[1] Chen Jing, Liao Yan, Zhang Hongzhong, et al. Survey on the current status of food allergy in children under two years old in three cities[J]. Chinese Journal of Pediatrics, 2012, 05(01):5-9.

[2]The prevalence of food allergy in infants in Chongqing, China[J]. pediatric allergy & immunology, 2011, 22(4):356-360.

[3]Arshad SH, Kurukulaaratchy RJ, Fenn M, et al. Early life risk factors forcurrent wheeze, asthma, and bronchial hyperresponsiveness at 10 years of age[J]. Chest, 2005, 127(2):502–508.

[4]Wang HT, Anvari S, Anagnostou K. The Role of Probiotics in Preventing Allergic Disease[J]. Children, 2019, 6(2), pii: E24.

[5]World Allergy Organization-McMaster University Guidelines for Allergic Disease Prevention (GLAD-P): Probiotics[J]. World Allergy Organ J, 2015,8(1):4.

[6]BerniCanani R, Di Costanzo M, Bedogni G, et al. Extensively hydrolyzed casein formula containing Lactobacillus rhamnosus GG reduces the occurrence of other allergic manifestations in children with cow's milk allergy: 3-year randomized controlled trial[J]. J Allergy Clin. Immunol. 2017, 139(6), 1906–1913.