Journal of the American Nutrition Association最新文献

Objective: Recent evidence suggests that gut microbial imbalance may contribute to the pathogenesis of obesity-related metabolic disorders, including cardiovascular diseases. Although the underlying mechanisms remain incompletely understood, numerous studies have investigated the modulation of gut microbiota through probiotic supplementation as a potential preventive or therapeutic approach. This randomized, prospective, triple-blind, placebo-controlled clinical trial aimed to evaluate the effects of Lactococcus lactis, a probiotic with anti-inflammatory properties, on cardiometabolic risk factors associated with obesity.

Method: Fifty-two adults with elevated waist circumference and at least one additional metabolic alteration, such as elevated blood pressure, triglycerides, or glucose or reduced high-density lipoprotein cholesterol were recruited and randomly assigned to either a probiotic or placebo group (n = 26 each) for 90 days. During the study, 5 participants from the probiotic group withdrew, resulting in 21 participants for the probiotic group's endpoint analyses. Neither group received guidance regarding food intake. Participants underwent assessments of anthropometry, body composition, dietary intake, and a range of biochemical markers.

Results: No significant improvements were observed on cardiometabolic risk parameters following L lactis LMG 27352 supplementation. Dietary analysis further revealed a significant rise in carbohydrate intake in both groups.

Conclusions: The findings of this study suggest limited clinical efficacy of L lactis LMG 27352 supplementation in metabolic disorders related to obesity under the conditions investigated. These results underscore the critical influence of dietary patterns, particularly sodium and carbohydrate intake, which may have modulated or counteracted any potential benefits of the probiotic strain.

Purpose: Aging is associated with reduced protein intake, increasing the risk of infections by damping the pulmonary and systemic immune response. Although whey protein supplementation improves systemic immune response, its effects on the pulmonary immune response are unknown.

Methods: This clinical trial composed by two groups (Control; n = 38; Age 69.31 ± 6.13; Men = 9; Women = 27) and (Whey; n = 27;; Age 68.14 ± 5.72; Men = 12; Women = 31) investigated whether isolated whey protein supplementation (IWPS) (25 g/day; 7 days/week; 3 months) could impact the pulmonary immune response, as a primary outcome, and the lung function, systemic cellular and humoral immune response, respiratory muscle strength, functional capacity, peripheral muscle strength and body composition as secondary outcomes.

Results: Three months of IWPS improved the lung function, such as force expiratory volume (FEV₁) (p < 0.048), forced expiratory volume in the first second/forced vital capacity ratio (FEV₁/FVC) (forced vital capacity) (p < 0.003), forced expiratory volume 25-75% (FEF25-75%) (p < 0.048), and peak expiratory flow (PEF) (p < 0.002). IWPS reduced the fractional exhaled nitric oxide (FeNO) (p < 0.015), interleukin 6 (IL-6) (p < 0.001) and tumoral necrosis factor alpha (TNF-α) (p < 0.001) levels, while increased IL-10 (p < 0.001) and Klotho (p < 0.013) in breath condensate, displaying an anti-inflammatory and anti-aging effect. Furthermore, IWPS improved systemic immune response, as showed by reduction on blood total leukocytes (p < 0.017), neutrophils (p < 0.049), and eosinophils (p < 0.009), and plasma levels of pro-inflammatory IL-6 (p < 0.005) and TNF-α (p < 0.001) and increased levels of anti-inflammatory IL-10 (p < 0.00005) and anti-aging protein Klotho (p < 0.0436). The functional capacity (p < 0.0031), expiratory muscle (p < 0.0001) and peripheral muscle strength (p < 0.0028) was improved by IWPS.

Conclusion: IWPS improved pulmonary and systemic immune response, lung function and functional capacity of older adults.

Objective: The probiotic properties of lactic acid bacteria (LAB) vary depending on the specific strain. This study aimed to evaluate the probiotic potential of LAB present in traditional dairy products using in vitro techniques.

Methods: Bacterial isolates from 63 artisanal dairy product samples, which included 6 kefir, 22 cheese, and 35 yogurt products, were analyzed. The isolates were subjected to tests for acid resistance, bile tolerance, antibiotic resistance, acidification capacity, hydrophobicity, exopolysaccharide (EPS) production, and antimicrobial activity. The isolates that gave positive results in these analyses were subsequently identified through 16S rRNA gene sequencing.

Results: The survival rates of the 93 isolates decreased significantly as the pH level lowered (p < 0.05), resulting in 76 isolates being classified as acid-resistant. The identical isolates also demonstrated tolerance to high concentrations of bile. Out of these, only 37 isolates were sensitive to all 12 antibiotics tested, while each isolate had varying levels of acidification capacity. Eight of these 37 isolates, which showed negative hydrophobicity ratios, were eliminated from further testing. All 29 remaining isolates exhibited EPS production, but only 17 showed an inhibitory effect against the selected pathogenic bacteria. Molecular identification of these 17 isolates revealed that 6 were Lactobacillus (Lact.) paracasei, 3 were Lact. crustorum, 2 were Lact. brevis, 2 were Lact. casei, 1 was Lact. plantarum, 1 was Lact. pentosus, 1 was Lact. helveticus, and 1 was Lact. rhamnosus.

Conclusions: The findings indicated that LAB strains naturally present in traditional dairy products possess significant probiotic characteristics. The direct use of the isolated strains in the development of functional foods and supplements within the local industry could contribute to the conservation and enhancement of the country's biodiversity and regional economic value. It is recommended that further comprehensive research be conducted to explore their potential for production and use as dietary supplements for humans.

Objective: The health of pancreatic β cells is known to be under the tight control of several genetic processes, including insulin signaling, regeneration (IGF-1, FOXO-1, JAK-2, STAT-1), and calcium signaling (GRK-2, PIAS-2, CALM-2). These signaling cascades regulate β-cell proliferation, differentiation, and insulin production and secretion and thus have been known to be the key players in diabetes pathogenesis as well as drug targets. This study aimed to elucidate the protective effect of Brassica juncea seed extract and β-cells dietary supplement.

Method: B juncea seed extract was given to male albino rats with streptozotocin (STZ) -induced diabetes for 42 days. Rats were divided into 5 groups: normal control, diabetic control, glibenclamide, extract and seed supplementation. At the end of study, pancreata were harvested for histopathologic analysis and quantitative reverse-transcription polymerase chain reaction for regeneration, insulin, and calcium signaling pathway genes.

Results: Histopathologic analysis showed severe pancreatic damage, including β-cell destruction and steatosis, in the diabetic control group, whereas treatment with B juncea extract and supplemented feed preserved pancreatic architecture, with only mild disruptions and improved β-cell morphology. Gene expression analysis revealed significant upregulation of genes (i.e., JAK-2, STAT-1, FOXO-1, IGF-1, GRK-2, PIAS-2, and CALM-2) in the diabetic control group, while treated groups exhibited moderated expression levels, suggesting improved regulation.

Conclusions: Results indicate that B juncea seeds are nutrient-rich that exhibit promising gene expression-modulating properties.

Objective: The bioaccessibility and potential bioavailability of β-carotene, resveratrol and gypenosides are significantly influenced by co-ingested food matrices.

Method: This study evaluated in vitro digestibility and potential bioavailability of these compounds using diverse carriers, including liquid (coffee, sprinkled and plain water), dairy (fruited and plain yogurt), solid (bread with sauce), and fruit/vegetable-based matrices (juices and smoothies).

Results: Among liquid matrices, coffee significantly enhanced the digestibility and bioavailability of resveratrol (23%, 21%) and gypenosides (17%, 16.44%) but markedly reduced β-carotene uptake (0.23%, 0.14%) due to interference with micelle formation. Conversely, sprinkled water moderately improved β-carotene bioavailability (3.13%, 2.31%). Solid matrices, particularly bread + sauce, enhanced bioavailability of β-carotene (11%) and resveratrol (2.40%) due to the presence of emulsifying lipids. Dairy matrices showed mixed effects; plain and fruited yogurts improved gypenosides bioavailability (6.93-7.98%) but had limited benefit for resveratrol and β-carotene due to protein compound interactions. Among fruit/vegetable matrices, tomato juice and smoothies consistently enhanced bioavailability for all three compounds, especially gypenosides (17%, 8.83%) and β-carotene (6.91%, 6.28%), likely due to lycopene content, natural emulsifiers, and disrupted cellular structure.

Conclusion: These findings highlight that delivery matrix critically affects the digestive fate and potential efficacy of β-carotene, resveratrol, and gypenosides and structurally disrupted matrices offering superior absorption potential.

Objective: Shatavarin IV, a steroidal saponin in Asparagus racemosus, is a traditionally recognized phytotherapeutic for the treatment of cognitive ailments. In the present study, the neuroprotective action of shatavarin IV was investigated in cultured SH-SY5Y cells.

Methods: Cells were treated with shatavarin IV (10 ng/ml) or proprietary ethanolic extract of shatavari root extract (SheVari4^®) containing 5% w/v shatavarin IV (100 ng/ml) in presence and absence of lipopolysaccharide (LPS) (1 µg/ml), an inducer of inflammatory response, brain-derived neurotrophic factor (BDNF), a neurotrophin, and K252a, an inhibitor of receptor tyrosine kinase. Proinflammatory cytokines IL-6 and TNF-α and anti-inflammatory cytokines IL-10 and TGF-β were assessed by qPCR. LPS induced oxidative stress was assessed through reactive oxygen species (ROS) and nitric oxide (NO) levels. Molecular docking was carried out to investigate the binding of shatavarin IV to tropomysin receptor kinase B (TrkB) and BDNF.

Results: In LPS-induced cells treated with shatavarin IV, IL6 and TNFα levels were reduced by 46% and 50%, respectively, and those of IL-10 and TGF-β were upregulated by 2.74 and 4.4 times with significant reductions in ROS and NO levels. Similar results were observed in presence of SheVari4^®. Addition of BDNF resulted in further augmentation of shatavarin IV-mediated protection. Administration of K-252a dampened this effect, which indicated that shatavarin IV exerted its effect in the TrkB-BDNF axis. The results also suggested that shatavarin IV probably exerted its effect by salvaging the endogenous BDNF with subsequent docking to TrkB as a BDNF-shatavarin IV complex. In silico docking of shatavarin IV-BDNF complex with TrkB resulted in a considerably strong binding energy of -10.3 kcal/mole, whereas that of shatavarin IV alone was comparatively weaker at -6.9 kcal/mole.

Conclusion: The results suggested that the primary bioactive component of Asparagus racemosus, shatavarin IV, exerted its neuroprotective effects on SH-SY5Y cell line via the TrkB-BDNF axis.

Background: Cardiovascular diseases (CVDs) remain the leading global cause of death, partly due to vascular dysfunction. Dietary supplements, including omega-3 fatty acids, are suggested to support vascular health, but their therapeutic effectiveness and optimal dosing are still uncertain.

Objectives: This systematic review and meta-analysis study assessed the efficacy and dose-response effects of omega-3 fatty acids on vascular health biomarkers in individuals with CVDs.

Data sources: A comprehensive search of PubMed, Scopus, Web of Science, and the Cochrane Library was conducted through May 2025.

Study selection: Eligible randomized controlled trials (RCTs) with a minimum intervention duration of four weeks.

Data extraction and synthesis: Two reviewers independently extracted data and assessed study quality. Data were synthesized as weighted mean differences (WMDs) with 95% confidence intervals (CIs). Risk of bias was assessed using the Cochrane tool, and the certainty of the evidence (CoE) was appraised using the GRADE framework.

Main outcome(s) and measure(s): The pulse wave velocity (PWV), augmentation index (AIx), and flow-mediated dilation (FMD).

Results: Twenty RCTs involving 1,208 participants were included, with 80% judged at low risk of bias. Omega-3 supplementation (0.3-4.7 g/day) showed no significant effect on PWV, including in subgroups with hypertension or established CVDs. In contrast, omega-3s improved AIx. FMD elevations were greater for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) than for alpha-linolenic acid. These findings were consistent across sensitivity analyses and supported by dose-response relationships, indicating that achieving approximately 1,650 mg EPA and 750 mg DHA may be important for optimizing vascular outcomes. The CoE ranged from moderate to low.

Conclusions: Omega-3 fatty acids may enhance endothelial function and reduce arterial wave reflection. Future trials with refined methods are needed to maximize clinical benefit.

Systematic review registration: Systematic review registered with PROSPERO, registration number CRD420251065121.

Objective: Military fluid replacement guidelines highlight the importance of hydration assessment prior to training and combat operations. Urine specific gravity (USG) is a commonly used assessment method to estimate hypohydration, typically based on a threshold of ≥1.020. However, recent evidence has suggested that this USG threshold may be influenced by body composition, primarily fat-free mass (FFM), thus a more liberal USG threshold (i.e., ≥1.025) may be warranted. The purpose of this exploratory study was to determine if there is a relationship between USG and FFM, a proxy for skeletal muscle, and compare FFM between those with and without elevated USG (≥1.020 and ≥1.025).

Methods: A sample of 346 military personnel provided urine samples for analysis via refractometer and had FFM estimated via bioelectrical impedance analysis (n = 165) or dual-energy x-ray absorptiometry (n = 181). Correlations (r) and linear regression were used to describe the relationship between FFM and USG. An ANCOVA with body composition device as a covariate determined the difference in FFM based on hydration status. Significance was set a priori at p < .05.

Results: Regardless of USG threshold, male military personnel were proportionally more likely to be considered hypohydrated. There was a significant positive, albeit weak, correlation between USG and FFM (r = 0.268, p < .001). Based on linear regression, 7.2% of the variance in USG was explained by FFM (p < .001). Military personnel with USG ≥1.020 or ≥1.025 had 5.0 kg (p < .001) and 7.6 kg (p < .001) more FFM than those considered euhydrated, respectively. No sex differences were identified.

Conclusions: These results suggest that USG is partially influenced by FFM and indicate that the liberal USG threshold for determining hypohydration may be the most appropriate for military personnel and other populations with higher FFM (e.g., strength and power-based athletes).

Background: Glycemic index (GI) and glycemic load (GL) are important dietary gears for managing diabetes and reducing chronic disease risk.

Objective: The objective of study was to prepare glycemic index (GI) and glycemic load (GL) table, for the first time, of 50 indigenous cereal-based products of Pakistan.

Methodology: Test foods were categorized into 6 categories: bread, rice, porridges, biscuits, snacks, and desserts. Every food product, 50 g of available carbohydrates, was tested on at least 10 healthy participants and blood glucose level was determined at set intervals through the finger-prick method. Glucose and white bread were used as reference foods. The GI and GL values were calculated from the incremental area under the curve (IAUC) of each test food as a percentage of every participant's average IAUC for the reference food. GL was calculated as the product of the test food's GI and the amount of available carbohydrate in a reference serving size.

Results: Results indicated that only seven test foods had low GI (55 or less), sixteen were classified as medium (56-69) and twenty-seven showed high GI values (>70).

Conclusion: The study concludes that majority of cereal based traditional foods/recipes have medium to high GI and GL.

Objective: Obesity is linked to an increased risk of diabetes, and the mechanisms through which excess fat negatively impacts the pancreas remain largely unclear. Our objective was to examine the impact of a high-fat diet (HFD) on pancreatic steatosis, oxidative stress, and inflammation, along with the potential protective and therapeutic effects provided by bee bread.

Method: Male Sprague-Dawley rats were randomly allocated into four groups (n = 6 per group): Standard diet (SD), HFD, HFD with bee bread (HFD + Bb) (0.5 g/kg body weight/d given concurrently for 12 wk as a protective model), and obese with bee bread (OB + Bb) (0.5 g/kg body weight/d given for 6 wk after obesity induction as a therapeutic model). After 12 wk, the body and organ; food intake; and blood serum levels were measured.

Results: Bee bread supplementation in both protective and therapeutic models notably decreased the Lee obesity index (303.1 ± 7.00; 308.6 ± 5.07), serum blood glucose (67.17 ± 4.45 mg/dL; 71.50 ± 3.94 mg/dL), serum insulin levels (0.72 ± 0.28 ng/mL; 1.22 ± 0.49 ng/mL), and lipid concentrations (TG, TC, FFA) in both serum and pancreatic tissue. Furthermore, bee bread inhibited Keap1 and enhanced Nrf2 cytoplasmic and nuclear translocations, resulting in improved pancreatic oxidative stress parameters. Moreover, bee bread reduced pancreatic inflammation and improved β-cell function and its regulator levels (AMPK, Sirt1).

Conclusions: These results showed that bee bread has protective and therapeutic effects against obesity-induced pancreatic lipotoxicity and dysfunction.