Objective. To assess the clinical efficacy of flavonoid supplements on allergic diseases. Design. Systematic review. Data Sources. MEDLINE/PubMed, Scopus, Web of Science, and Embase databases were searched from inception to September 2021. Eligibility Criteria for Selecting Studies. Eligible study designs were randomized controlled trials that investigated the effect of flavonoids applied to allergic diseases. Results. This review included 15 randomized controlled trials, including allergic rhinitis/cedar pollinosis ( ), asthma ( ), and atopic dermatitis ( ). A total of 990 participants aged 6 to 69 years were included in these studies. Globally, 12 studies (80%) revealed some benefits of flavonoids (isolate or combined with other compounds) in allergic patients, while three studies (20%) reported no statistically significant impact on symptom scores and/or lung function. No severe adverse events related to treatment were reported. According to the GRADE system, the outcomes evaluated were of low to moderate quality of evidence. Conclusions. Overall, this review suggests that the administration of flavonoids may provide a viable strategy for mitigating allergic symptoms. Future trials with high methodological quality are needed to establish definitive conclusions. This trial is registered with PROSPERO registration no. CRD42021237403.

Context: With the increased use of fermented products and probiotic foods, interest in knowing their benefits and safety of their intake is increasing. Objective: The current systematic review investigated the effects of probiotics supplementation on short-chain fatty acid (SCFA) levels. Methods: A systematic review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Medline/PubMed, Scopus, Web of Science, and Embase databases were searched from inception to February 2024, including only randomized controlled trials. Results: A total of 30 studies were included, involving 1499 participants. The vast majority of trials investigated Bifidobacterium and Lactobacillus strains. These were categorized into healthy adults (n = 6), gastrointestinal/inflammatory diseases (n = 7), metabolic diseases (n = 6), elderly individuals (n = 3), children (n = 4), and infant formula (n = 4). Most studies evaluated isolated strain supplementation (n = 12), followed by fermented beverages (n = 11) and probiotic mixes (n = 3). Globally, 16 studies (53.3%) revealed an increase in at least 1 SCFA in participants supplemented with probiotics. In comparison, 5 studies (16.7%) reported a reduction and 9 studies showed no statistically significant impact in their findings (30%). The subgroup evaluation showed heterogeneity in the results, with low to moderate evidence grading levels. Conclusion: Probiotics supplementation during childhood was the intervention period more effective in increasing fecal SCFAs and immunoglobulin A (IgA) levels (GRADE: moderate/high-certainty evidence). Systematic Review Registration: PROSPERO registration no. CRD42024513221.