This integrative aimed to evaluate the effects and the potential mechanism of action of prebiotics, probiotics, and synbiotics on constipation-associated gastrointestinal symptoms and to identify issues that still need to be answered. A literature search was performed in the PubMed database. Animal models (n = 23) and clinical trials (n = 39) were included. In animal studies, prebiotic, probiotic, and synbiotic supplementation showed a decreased colonic transit time (CTT) and an increase in the number and water content of feces. In humans, inulin is shown to be the most promising prebiotic, while B. lactis and L. casei Shirota probiotics were shown to increase defecation frequency, the latter strain being more effective in improving stool consistency and constipation symptoms. Overall, synbiotics seem to reduce CTT, increase defecation frequency, and improve stool consistency with a controversial effect on the improvement of constipation symptoms. Moreover, some aspects of probiotic use in constipation-related outcomes remain unanswered, such as the best dose, duration, time of consumption (before, during, or after meals), and matrices, as well as their effect and mechanisms on the regulation of inflammation in patients with constipation, on polymorphisms associated with constipation, and on the management of constipation via 5-HT. Thus, more high-quality randomized control trials (RCTs) evaluating these lacking aspects are necessary to provide safe conclusions about their effectiveness in managing intestinal constipation.

Context: Clinical trials have investigated the effect of probiotics on postsurgical complications in colorectal cancer (CRC). However, so far, there are no systematic reviews evaluating the effect of probiotics and synbiotics on the clinical or infectious postsurgical complications of colorectal cancer.Objective: The objective of this review was to synthesize the best available evidence on the effects of the use of probiotics or synbiotics on pre-, peri-, and post-operative complications of CRC surgical resection.Data Sources: A search of the PubMed, Embase, LILACS, Scopus, Cochrane, Web of Science, ProQuest, and Google Scholar databases was conducted for clinical trials published up until January 2022.Data Extraction: The population characteristics, period and protocol of supplementation, and postoperative complications were extracted and reported. A random-effects model was used to estimate the effect of probiotic and synbiotic treatment on these variables.Data Synthesis: In total, 2518 studies were identified, of which 16 were included in the qualitative synthesis and 13 in the meta-analysis. Overall, probiotic supplementation reduced the incidence of ileus (odds ratio [OR] = .13, 95% confidence interval [CI]: .02, .78), diarrhea (OR = .32, 95% CI: .15, .69), abdominal collection (OR: .35, 95% CI: .13, .92), sepsis (OR = .41, 95% CI: .22, .80), pneumonia (OR = .39, 95% CI: .19, .83), and surgical site infection (OR = .53, 95% CI: .36, .78). The results of the subgroup analysis indicated that lower dose (14 days), and being administrated ≤5 days before and >10 days after surgery was more effective at reducing the incidence of surgical site infection.Conclusion: Probiotics and synbiotics seem to be a promising strategy for the prevention of postoperative complications after CRC surgery. Larger, high-quality randomized controlled trials are needed to establish the optimal treatment protocol for the use of probiotics and synbiotics in preventing postoperative complications for CRC surgery.

Vitamin D deficiency is considered a global public health issue, even in low-latitude countries where there is abundant sunlight radiation. Nevertheless, the prevalence of vitamin D insufficiency and deficiency in the South American continent has not been well characterized. The aim of this review was to estimate the prevalence of vitamin D deficiency (25-hydroxy-calciferol < 20 ng/mL) in South American populations. Seven electronic databases (MEDLINE, Web of Science, Embase, Biblioteca Virtual de Saúde, SciELO, Scopus, and Google Scholar) were searched systematically for observational studies published before July 1, 2021, and reporting vitamin D status of healthy adults in South America. Data were extracted using a standardized form. Risk of bias was assessed by the Joanna Briggs Institute Critical Appraisal Instrument for Studies Reporting Prevalence. All steps were conducted independently by two authors. Data were pooled using a random-effects model. Stratified meta-analysis and meta-regression were conducted (R software). Of 9460 articles identified, 96 studies with a total of 227 758 participants were included. The overall prevalence of vitamin D deficiency was 34.76% (79 studies; 95%CI, 29.68–40.21; I² = 99%). There were significant differences in prevalence rates related to age, sex, country, latitude, season, and year of publication. The prevalence of vitamin D deficiency is unexpectedly elevated in South American populations. Public health strategies should include efforts to prevent, detect, and treat vitamin D deficiency. PROSPERO registration number CRD42020169439.

Context: The effects of probiotics on gastrointestinal (GI) symptoms have been increasingly investigated, particularly that of Bifidobacterium animalis. Clinical trials so far have shown differing evidence regarding these effects in healthy adults. Objective: To synthesize the published evidence on the effects of B. animalis subspecies lactis on GI symptoms (GIS) in healthy adults. Data Source: A search of the Medline, Embase, Lilacs, Scopus, Web of Science, ProQuest, and Google Scholar databases was conducted for reports on randomized controlled trials published up to October 2021. Data Extraction: Population characteristics and data on colonic transit time (CTT), stool consistency, defecation frequency, abdominal pain, bloating, flatulence, volunteer compliance, and adverse events were extracted. A random-effects model was used to estimate the effect of probiotic treatment on these variables. Data Synthesis: In total, 1551 studies were identified, of which 14 were included in the qualitative synthesis and 13 in the meta-analysis. Overall, probiotic supplementation increased defecation frequency (standardized mean difference [SMD], 0.26; 95%CI, 0.13–0.39). Subgroup analysis revealed a decrease in CTT (SMD, −0.34; 95%CI, −0.62 to −0.07) in short-term treatment (≤14 d) and an improvement in stool consistency (SMD, 0.76; 95%CI, 0.44–1.08) in individuals without GIS. No improvement in abdominal pain and bloating was found. Conclusions: B. animalis subspecies lactis supplementation may increase defecation frequency and, in short-term treatment, may reduce CTT in healthy adults and improve stool consistency in individuals without GIS. More high-quality randomized controlled trials are needed to develop a clinical protocol for the use of this strain to improve these symptoms. Systematic Review Registration: PROSPERO registration no. CRD42020154060.

Background: While several studies have investigated the association between vitamin D deficiency and biochemical parameters, the results are still inconsistent and mostly overlook seasonal variations. This study explored the relationships between 25-hydroxy-vitamin D (25(OH)D) concentrations, biochemical markers, and seasonal variation among young males and females. Methods: A cross-sectional study was conducted among 203 individuals aged 18–24 years of both sexes residing in Brasilia, Brazil (latitude: 15°S). Sociodemographic variables, season of blood collection, and serum levels of 25(OH)D, total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides, glycated hemoglobin (HbA1c), glucose, insulin, hs-CRP, parathyroid hormone, ionized calcium, and alkaline phosphatase were included. Descriptive statistics and differences among groups, correlations, and linear regression tests were performed. Results: The mean age of the participants was 21.17±1.7 years, and the mean serum 25(OH)D level was 25.76±7.0 ng/mL. Of the participants, 50.7% had vitamin D insufficiency (20 to 29.9 ng/mL), and 23.2% were vitamin D deficient (≤20 ng/mL). Vitamin D deficiency was higher in the spring (53.2%) and among females (29.5%). In young men with vitamin D insufficiency/deficiency (≤29.9 ng/mL) (n = 49), 25(OH)D levels were inversely correlated with HOMA-β (r = -0.234, p = 0.032) and triglyceride (r = -0.415, p = 0.003) levels. However, there were no significant correlations between 25(OH)D concentrations and biochemical markers among women with insufficient and deficient vitamin D levels. Conclusion: This study found a high prevalence of vitamin D insufficiency/deficiency among young individuals living in Brasília, Brazil, particularly women and during the spring season. Our findings suggest that lower 25(OH)D levels (≤29.9 ng/mL) may be associated with insulin resistance and an increased risk of cardiovascular disease in young men studied. However, further studies with larger representative samples are needed to explore the mechanisms underlying the association between vitamin D and biochemical parameters.