Journal of Dietary Supplements最新文献

The market for olive leaf dietary supplements is expanding rapidly and is valued at $437.15 million today. However, information on the control of these products is sketchy and the origin and variety of olives are rarely stated. The aim of this research was to validate a simple and rapid screening method for oleuropein determination in olive leaf dietary supplements. A matrix blank was prepared by removal of oleuropein from a mixture of dietary supplements and the matrix was then spiked with known concentrations to create a spiked matrix calibration curve in the range 5 - 40% oleuropein. Five replicate extractions and analyses of the matrix standards were carried out over 10 days. Precision was less than 6% RSD and linearity was demonstrated by the Fischer test. Extraction recovery was > 90% and there was a strong linear relationship between authentic and matrix standards. All tested products conformed to the label claim which was strongly correlated with total polyphenols measured by the Folin-Ciocalteau method. Antioxidant activity was measured by the DPPH assay and was found to be strongly correlated with total phenol content and oleuropein concentration.

Objective: In this systematic review and meta-analysis of clinical trials, we investigated the effect of pomegranate on vascular endothelial function markers.

Methods: We searched PubMed, Scopus, Web of Science, and the Cochrane Library until September 2024. Clinical trials that investigated the effect of pomegranate juice, extract, or its components on markers of vascular endothelial function, including flow-mediated dilation (FMD), intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), E-selectin, nitric oxide (NO), interleukin 6 (IL-6), IL-1, and IL-10, in healthy or diseased adults ages ≥ 18 years were eligible to be included. The quality of studies was assessed using the Cochrane tool. Random-effects meta-analysis was used to pool standardized mean differences (SMD) and 95% CI for the outcomes assessed by at least three studies.

Results: Nineteen studies were included. Analysis of studies indicated a nonsignificant effect on VCAM-1 (SMD: -041, 95%CI: -2.53 to 1.71, I²= 83.6%, n = 3), while a significant reduction in ICAM-1 was observed (SMD: -0.63, 95% CI: -0.85 to -0.40, I² = 0.0%, n = 3). Pooled analysis of fourteen studies on IL-6 indicated a significant reduction (-0.58, 95% CI: -0.98 to -0.19, I² = 82.63%). The results of the three studies on E-selectin were inconsistent. The FMD and NO were assessed in only one study.

Conclusions: Pomegranate is effective in improving IL-6 and ICAM-1, but not VCAM-1.

Infertility affects a growing number of families worldwide. Male factors contribute to 20-50% of infertility cases, and their improvement can help reduce the rising infertility rates. Recent studies have increasingly shown that fatty acids (FAs) can modulate sperm quality and significantly impact male fertility. This review investigates recent studies on the role of FAs in infertility, including their impact on sperm quality, FA profiles in infertility-related conditions, and the therapeutic potential of dietary and supplemental FAs. Our review reveals that omega-3 polyunsaturated fatty acids (PUFAs) are crucial for spermatogenesis and sperm function, and their imbalance with omega-6 PUFAs is associated with oxidative stress. FA metabolism is a promising target for infertility management. Precision nutrition strategies may complement conventional therapies, but further RCTs are needed to standardize protocols.

Constipation is a prevalent symptom in adults and has been linked to an increased risk of serious complications, including cardiovascular and renal diseases. This study evaluated the effect of apple polyphenols on defecation among Japanese adults with a body mass index of ≥25 kg/m² and <30 kg/m² experiencing constipation who were otherwise healthy. After screening for eligibility, 24 participants were randomly assigned to either the Apple polyphenol or Placebo group in equal numbers. Participants consumed four tablets/day of either unripe apple-derived polyphenols (600 mg/day) or a placebo after breakfast with water for 12 wk. The primary outcome was weekly defecation frequency. Secondary outcomes included the number of days with defecation, the volume and feeling of defecation, the shape and smell of stools, fecal Akkermansia muciniphila counts, physical measurements, body composition, and blood lipid profile. The analysis included 12 participants in the Apple polyphenol and 11 in the Placebo group. After the 12-week intervention, the Apple polyphenol group had a significantly higher weekly defecation frequency versus the Placebo group (7.0 ± 2.1 vs. 4.9 ± 1.4 times; group difference: 2.2 times [95% CI 0.8-3.6], p = 0.004). No significant inter-group differences were observed in fecal A. muciniphila counts, physical measurements, body composition. While blood triglyceride levels tended to be lower in the Apple polyphenol group. These findings suggest that the consumption of polyphenols derived from immature apples may increase defecation frequency and ameliorate constipation; however, it appears not to affect A. muciniphila.

Clinical trial registry: UMIN000050393.

Background: Several epidemiological studies and intervention trials have demonstrated that grapes and blueberries, which are rich in flavanols, can lower the risk of cardiovascular disease. However, the mechanisms of action of these compounds remain unclear due to their low bioavailability.

Objective: This study aimed to characterize the sensory properties, blood flow velocity, and oxidative stress of a polyphenol rich grape and blueberry extract (PEGB) containing approximately 16% flavanols (11% monomers and 4% dimers).

Method: A sensory property of PEGB was compared with quercetin at uniform concentration using healthy young subjects. In addition, the reactivity of PEGB with O₂^•- was also compared with quercetin utilizing a luminescence method. Furthermore, the effect of a single administration of PEGB on the blood flow velocity of skeletal muscle arterioles was investigated using a laser Doppler method in rats.

Results: At a concentration where quercetin was barely tasteful, flavanol in PEGB exhibited a robust astringent taste. Furthermore, under pH conditions mimicking the oral cavity and intestinal tract, PEGB promoted O₂^•- production at low concentrations and scavenging O₂^•- at high concentrations. In contrast, quercetin demonstrated antioxidant activity. A single oral administration of PEGB significantly increased the blood flow velocity of skeletal muscle arterioles.

Conclusion: The results demonstrate that PEGB exhibited a pronounced astringent taste, O₂^•- production at low concentrations in neutral pH environments, and significantly enhanced blood flow to skeletal muscle following a single administration to rats. These findings highlight the necessity for further investigation into the causal relationships between oral perception, redox properties, and bioactivity of polyphenols.

The controversial status of N-acetylcysteine (NAC) as a dietary supplement ingredient has renewed interest in its origin. This opinion article critically examines the scientific literature to investigate whether NAC is a naturally occurring compound, with a particular focus on its potential presence in plants. The primary objective of this opinion is to determine the natural occurrence of NAC, specifically within herbal matter. The classification of NAC as a dietary ingredient falls outside the scope of this analysis. We will rigorously evaluate the methodologies implemented in establishing NAC's presence in plant or herbal sources, specifically in Allium species which are often touted to contain NAC. By analyzing the strengths and weaknesses of prior research, we aim to clarify the evidence supporting the origin of NAC.

Adiponectin and leptin are pivotal adipokines regulating metabolic homeostasis, with dysregulation linked to obesity, insulin resistance, and related metabolic disorders. Vitamin E, a potent antioxidant, has been proposed to modulate adipokine secretion, but existing studies report inconsistent findings. This systematic review and meta-analysis aimed to evaluate the impact of vitamin E oral supplementation on serum adiponectin and leptin levels in adults. Systematic searches were performed in major electronic databases up to August 2025 to identify eligible randomized controlled trials (RCTs). Extracted data were analyzed using STATA, and pooled effect estimates were calculated as weighted mean differences (WMDs) with 95% confidence intervals (CIs). The pooled analysis of 10 RCTs (14 effect sizes) showed that vitamin E supplementation did not significantly alter serum adiponectin (WMD: 0.67 ng/mL; 95% CI: [-0.11 - 1.44]; p = 0.093) or leptin levels (WMD: -3.60 ng/mL; 95% CI: [-7.45 - 0.25]; p = 0.067). Subgroup analyses revealed that long-term supplementation (>12 wk) significantly increased adiponectin (WMD: 1.60 ng/mL; p = 0.039), particularly in patients with nonalcoholic fatty liver disease (NAFLD) (WMD: 4.28 ng/mL; p < 0.001). Additionally, vitamin E significantly reduced leptin levels in NAFLD patients (WMD: -5.45 ng/mL; p < 0.001). This meta-analysis found no significant overall effect of vitamin E on adiponectin and leptin levels; however, long-term supplementation appears beneficial, particularly in patients with NAFLD. Heterogeneity in study design, dosage, and duration highlights the need for further well-designed RCTs to clarify the metabolic and therapeutic roles of vitamin E.

We examined the influence of dietary α-lipoic acid (LA; R enantiomer) supplementation in obese-complicated pregnancies on maternal postpartum body weight and metabolic health. Forty-eight female Sprague-Dawley rats were randomized into three dietary groups throughout pre-pregnancy, gestation, and lactation: (i) a low-calorie control diet (CON); (ii) a high calorie obesity-inducing diet (HC); or (iii) the HC diet with 0.25% LA (HC+LA). Following offspring weaning, all mothers were switched to the CON diet for a postpartum period of 140 days to assess maternal body weight and markers of metabolic health. HC-fed mothers showed excessive (p < 0.05) gestational weight gain (GWG), higher (p < 0.05) postpartum body weight, reduced (p < 0.05) glycemic control (lower glucose:insulin ratio) and higher (p = 0.06) hepatic cholesterol concentration versus CON mothers. In contrast, HC+LA mothers demonstrated lower (p < 0.05) body weight throughout the experimental period compared with HC mothers, primarily due to a marked reduction in GWG. Although LA did not protect (p > 0.05) against reduced glycemic control, it did alter several aspects of lipid metabolism including reduced serum HDL-C and a lower concentration of hepatic cholesterol which was mediated partly through a reduction in low-density lipoprotein receptor expression. We conclude that maternal obesity during pregnancy leads to a longer-term detrimental impact on weight gain and glycemic control, even after switching to a low-calorie postpartum diet. Maternal LA supplementation may be able to partially offset these effects, likely by protecting against excessive GWG during pregnancy. However, further work is required to determine the consequences of reduced serum HDL-C in LA-supplemented mothers.

Although creatine monohydrate (CM), leucine, and polyphenols have been independently researched, there is a lack of research on the effects of a supplementation blend containing trisodium citrate, CM, leucine, and blueberry extract (TCLB) on muscle strength, endurance, and size. This study compared the effects of 8 wk of supplementation with TCLB versus CM and placebo (PLA) combined with resistance training on leg extension strength, endurance, and muscle size. Twenty-eight recreationally active men ingested either TCLB (n = 10), CM (n = 10), or PLA (n = 8) during 8 wk of resistance training. Leg extension 1-repetition maximum (1RM), leg extension repetitions-to-failure at ∼80% of pre-training 1RM, individual quadriceps cross-sectional area (CSA) values, and the sum of the CSA values (CSA_sum) were assessed at pre-training and post-training. Separate one-way ANCOVAs covaried for pre-training values were used to analyze differences in adjusted post-training means. Separate Chi-squared tests were used to analyze differences between groups in the proportion of subjects that exceeded the minimal important difference (MID). There were no group differences (p > 0.05) for leg extension 1RM, leg extension repetitions-to-failure, rectus femoris CSA, vastus lateralis CSA, or vastus medialis CSA. The TCLB group demonstrated greater (p ≤ 0.05) adjusted post-training means and proportions of subjects who exceeded the MID for the CSA_sum and vastus intermedius CSA than the PLA group, but the TCLB group did not differ (p > 0.05) from the CM group for those variables. The CM group (p ≤ 0.05) exhibited a greater proportion of subjects who exceeded the MID for the CSA_sum than the PLA group. These findings indicated that 8 wk of supplementation with TCLB and CM combined with resistance training increased the overall quadriceps muscle size greater than the PLA, but TCLB did not differ from CM. Furthermore, the groups did not differ in the training-induced increases in leg extension strength and endurance.

Modafinil (brand name Provigil®) is a Schedule IV (U.S.) drug used for the treatment of narcolepsy and sleep disorders. It is also known to be used recreationally. Analogs of modafinil, including adrafinil, remain unapproved and/or unscheduled. The lack of scheduling has made these analogs a popular target for recreational use and inclusion in dietary supplements. However, the use of controlled substances (or their analogs) without the care of a physician presents a public health risk. Preliminary nontargeted analyses in our laboratory revealed the presence of adrafinil in several dietary supplements, highlighting the need for an analytical method to identify modafinil analogs in supplements. A liquid chromatography high resolution mass spectrometry (LC-HRMS) method was developed and validated to quantitate modafinil, plus four novel unscheduled modafinil analogs: adrafinil, CRL-40,940, CRL-40,941, and N-methyl-4,4-difluoromodafinil. This method was then applied to four samples of products marketed as dietary supplements collected via undercover purchase. These four products were marketed as nootropics or cognitive enhancers and labeled to contain adrafinil. Adrafinil was found in all four samples. The identification of modafinil analogs in this context is important so that consumers are not, knowingly or unknowingly, consuming these active pharmaceutical ingredients in products marketed as dietary supplements.