Background/Objectives: Functional constipation (FC) commonly affects middle-aged and older adults, but current pharmacological treatments have limitations. Postbiotics may offer safety advantages, but clinical evidence is limited. This randomized controlled trial evaluated the efficacy and safety of a heat-inactivated two-strain Lacticaseibacillus paracasei fermented milk in adults with FC. Methods: One hundred adults aged 45–75 years with Rome IV-defined FC received the fermented milk or placebo for 4 weeks. The primary outcome was the change in weekly spontaneous bowel movement (SBM) frequency from baseline to week 4. Secondary outcomes included complete spontaneous bowel movement (CSBM) frequency, whole-gut transit time (WGTT), constipation symptom scores, quality of life, serum biomarkers, and adverse events. Primary analysis was per-protocol (n = 96); intention-to-treat analysis was applied to primary and key secondary outcomes. Results: Dropout was 4% (n = 4, 2 per group), and adherence was >80% in both groups. The intervention showed no significant benefit over placebo for the primary outcome or for most secondary clinical outcomes. Although both groups improved within-group, no significant between-group differences were observed at week 4 for changes in SBM (MD = −0.14, 95% CI: −0.85, 0.57; p = 0.683), CSBM (MD = 0.27, 95% CI: −0.61, 1.15; p = 0.543), or WGTT (MD = −1.55 h, 95% CI: −7.65, 4.55; p = 0.614). Symptom and quality-of-life scores also did not differ between groups. Exploratory biomarker analyses showed significantly greater increases in serum VIP and ACh in the intervention group (VIP: MD = 105.23 ng/L, p < 0.001; ACh: MD = 42.95 ng/L, p = 0.035). No adverse events were reported. Conclusions: Four weeks of this postbiotic was safe but did not significantly improve bowel function or symptoms in the overall FC population. The increases in serum VIP and ACh suggest engagement of neurotransmitter-related pathways; however, these exploratory findings do not imply causation or clinical efficacy and warrant confirmation in longer-duration trials (Clinical Trial Registry: ChiCTR2500111771).

Background: Chronic constipation lacks effective long-term treatments. Non-digestible oligosaccharides (NDOs) are short-chain carbohydrates that resist digestion and may improve bowel function. This systematic review and meta-analysis examines the effect of NDOs on constipation-related outcomes in humans. Methods: We searched Ovid MEDLINE, Embase, and Web of Science (2010–May 2025) for randomized controlled trials (RCTs) comparing NDOs with placebo, reporting stool frequency, stool consistency, fecal pH, or short-chain fatty acids (SCFAs). Data were pooled using random-effects meta-analysis. All effect estimates are reported as standardized mean differences (SMDs) with 95% confidence intervals (CIs). Subgroups were analyzed based on baseline constipation status and treatment duration. Results: We included 20 RCTs (1786 participants) evaluating seven NDO types. NDO supplementation significantly increased stool frequency overall, with larger effects in constipated individuals (SMD 0.99, 95% CI 0.58–1.28) than in non-constipated population (SMD 0.30, 95% CI 0.10–0.51). By duration, shorter interventions (≤3 weeks) yielded greater frequency gains (SMD 0.89, 95% CI 0.40–1.38) than longer ones (SMD 0.24, 95% CI 0.09–0.38). While the overall effect on stool consistency was non-significant, constipated patients (SMD 0.46, 95% CI 0.19–0.74) and short-term trials (SMD 0.20, 95% CI 0.03–0.37) showed modest improvements. NDOs also lowered fecal pH (SMD −1.02, 95% CI −1.25–−0.79). Data on SCFAs were inconclusive and based on very limited studies. Conclusions: NDOs modestly increase stool frequency and lower fecal pH, with greater effects in constipated individuals and short-term interventions. However, evidence certainty remains low due to heterogeneity and study limitations. Further studies are needed to establish clinical utility.

Background/Objectives: Current evidence on the diabetes prevention benefit of substituting red meat with white meat remains inconsistent and is predominantly based on Western populations. This research examined whether the benefits of such dietary substitution depend on habitual red meat intake levels. Methods: This prospective analysis included 12,143 adults from the China Health and Nutrition Survey (2004–2015). Dietary intake was assessed by multiple 24 h recalls supplemented by a household food inventory. Incident diabetes was identified via self-report and supplementary biochemical data. Estimates of hazard ratios (HRs) and 95% confidence intervals (CIs) were obtained through Cox proportional hazards modeling. Dose–response relationships were examined using restricted cubic splines. Substitution effects were evaluated within strata defined by baseline red meat intake (<75 vs. ≥75 g/day). Results: During 83,046 person-years of follow-up, 687 incident diabetes cases occurred. U-shaped associations were identified for both red meat (lowest risk at 75 g/day) and white meat (lowest risk at 60 g/day) consumption in relation to diabetes risk (p-nonlinearity < 0.0001). Substitution was not associated with diabetes risk in the low-intake stratum (<75 g/day, p = 0.107). Conversely, in the high-intake stratum (≥75 g/day), replacing 50 g/day of red meat with white meat was associated with a 34% lower diabetes risk (HR: 0.66; 95% CI: 0.51, 0.86; p = 0.002). Conclusions: Meat intake shows a nonlinear association with diabetes risk in Chinese adults. The potential benefit of substituting white meat for red meat is conditional, with a more pronounced effect observed among individuals with high habitual red meat consumption, which may support the development of targeted dietary guidance for this subgroup.

Background/Objectives: Dairy and soybean are important potential dietary sources of bone health. However, their comparative effectiveness and the role of specific components remain unclear. In this network meta-analysis (NMA), we aimed to compare the effects of various dairy and soy products (food level) and their key bioactive components (component level) on bone health in healthy women. Methods: We systematically searched PubMed, Embase, Cochrane Library, and Web of Science (up to 28 February 2025) for randomized controlled trials. A frequentist random-effects NMA was used to compare interventions for lumbar spine (LS) and total body (TB) bone mineral density (BMD) and bone turnover markers [osteocalcin (OC), deoxypyridinoline (DPD)]. Mean differences (MDs) and 95% confidence intervals were pooled. Interventions were ranked using the surface under the cumulative ranking curve (SUCRA). Results: Sixty RCTs involving 6284 participants (mean age: 54.2 years) were included. At the food level, no dairy or soy interventions significantly improved outcomes versus control, although milk + yogurt ranked numerically highest based on SUCRA values. At the bioactive-component level, the combination of casein + whey protein (MD 0.04 g/cm², 95% CI 0.01–0.06) and soybean protein (MD: 0.03 g/cm², 95% CI: 0.01–0.05) significantly increased TB BMD. Whey protein alone (SUCRA 74.4% for LS BMD) and casein + whey protein (SUCRA 86.3% for TB BMD and 75.9% for DPD) were among the highest-ranked interventions for bone health. Conclusions: The combination of milk and yogurt may be relatively promising among dairy products for bone health. Whey protein appears to be a key bioactive component beneficial for women’s bone health.