Recent estimates indicate that diarrheal mortalities have decreased to 2.5 million individuals annually. However, despite these recent findings, diarrhea remains the primary cause of death among children under five years old (15 %).
Current strategies for controlling diarrhea include preventing and managing dehydration through oral or intravenous fluids, as well as sustaining breastfeeding for infants. However, in recent years, there has been increasing recognition of the hygiene benefits of probiotics, supported by scientific research. Currently, strong evidence exists for their use in preventing and treating certain human diseases. Several studies have demonstrated the preventive effects of certain probiotics in reducing gastrointestinal complications. Therefore, the present study aims to evaluate the effect of a synbiotic containing probiotics, specifically L. rhamnosus, L. reuteri, Bifidobacterium infantis bacteria, and FOS, on acute diarrhea in children.
The results of the present study showed that the mean dehydration percentage and the time between diarrhea and recovery were significantly lower in the placebo group compared to the synbiotic group (P < 0.05). On the other hand, the decreasing rate of diarrhea frequency was significantly higher in the synbiotic group compared to the placebo group (P < 0.05). However, there was no significant difference between the two groups for hospitalization duration, weight at the beginning of hospitalization, and weight at discharge (P > 0.05). Various studies have yielded contradictory results regarding the application of probiotic compounds in the treatment of childhood diarrhea, as some have reported positive effects of these compounds, while others have stated that these compounds have no positive effect on the process of childhood diarrhea.
In several studies,
L. rhamnosus was recommended to treat acute gastroenteritis (
6,
7).
Canani et al. observed that the consumption of
L. rhamnosus GG could decrease the daily frequency of bowel movements and the duration of diarrhea in children compared to the control group (
8).
Unlike the above studies, in which the positive effects of probiotic consumption were mentioned, some studies have shown that these compounds have almost no positive effect in treating diarrhea. Costa-Ribeiro et al. examined the effect of
L. rhamnosus GG in their study in Brazil involving 124 male infants (1 to 24 months) hospitalized with moderate to severe diarrhea (
9). They found no significant decrease in diarrhea duration or the amount of bowel movements in children receiving
L. rhamnosus GG compared to the control group (
9).
In a meta-analysis by Szajewska et al., published in 2007,
L. rhamnosus GG was found to have moderate clinical benefit in the treatment of acute diarrhea (
10). Several review studies have assessed the effect of probiotics on diarrhea. Szajewska and Mrukowicz further evaluated acute diarrhea lasting more than three days in 731 infants and children in a systematic review of 8 randomized controlled studies (
11). This analysis showed that diarrhea lasting 3 days or more in the group receiving
L. rhamonosus GG probiotic was decreased by 40 % compared to the control group. In a recently published systematic review by Szajewska et al., they found that
L. rhamnosus reduced diarrhea duration (with a greater impact in European countries) and hospitalization (
12). However, in the study by Schnadower et al., the administration of
L. rhamnosus GG had no effect on the outcome of children with gastroenteritis (
13).
Probiotics also significantly decreased the duration of diarrhea compared to the control group. The meta-analysis by Van Niel et al. evaluated randomized studies of seven species of lactobacillus in 675 children (
14). Probiotics reduced diarrhea duration to 0.7 days and decreased the frequency of diarrhea from 2 days to 6.1 excretions (
14).
In the recent study by Szymanski and Szajewska,
L. reuteri DSM17938 showed no significant efficacy in treating acute gastroenteritis (
15). However, in the study by Francavilla et al.,
L. reuteri DSM17938 exhibited significant efficacy in reducing the duration, frequency, and recrudescence rate of acute gastroenteritis (
16). In the recent systematic review, the use of
L. reuteri was associated with a reduced duration of diarrhea and hospitalization (
17).
Bifidobacterium infantis may reduce diarrhea among healthy infants (
18).
Fructooligosaccharides also has a beneficial effect in the treatment of rotavirus-induced diarrhea (
19). The study by Vandenplas et al. on a synbiotic supplement containing FOS and probiotic strains of
Streptococcus thermophilus,
L. rhamnosus,
L. acidophilus,
Bifidobacterium lactis, and
Bifidobacterium infantis resulted in earlier normalization of stool consistency in acute infectious diarrhea (
20). More recently, a meta-analysis showed a potential beneficial role of probiotics in the treatment of acute diarrhea in children (
21). In another study, multi-strain probiotics improved the efficacy of standard diarrhea treatment regardless of etiology (
22). Additionally, a mixture of
Streptococcus thermophilus,
L. rhamnosus,
L. acidophilus,
Bifidobacterium lactis,
Bifidobacterium infantis, and FOS normalized stool consistency more rapidly than placebo (
23). However, in the recent study, a combination of
L. rhamnosus-
L. helveticus probiotic did not prevent the development of moderate-to-severe gastroenteritis in children (
24).
5.1. Conclusions
The results of the present study showed that the concurrent application of synbiotic drops, including Lactobacillus reuteri, Lactobacillus rhamnosus, Bifidobacterium infantis, and FOS in the treatment of non-infectious diarrhea in children aged 6 - 24 months is effective in reducing the time of recovery, number of evacuations, and duration of hospitalization. However, these results are not definitive, and further studies with larger sample sizes are needed to determine the efficacy, optimal dosage, time required for effectiveness, and mechanism of action of various probiotic species and strains. Additionally, the strains and effective treatment doses for each disease should be specified to utilize probiotics as adjunct treatment alongside conventional diarrhea treatments in children.
5.2. Limitations of the Study
Include single-center study and follow-up of the cases with a limited sample size.