Lycopene is a lipophilic unsaturated carotenoid exhibiting a strong singlet oxygen-quenching ability. Herein, we investigated the effect of lycopene intake on the fasting blood glucose (FBG) level by conducting a systematic review and meta-analyses. We searched 15 databases (from the earliest date to June 2022 for PubMed or to August or September 2018 for the other databases) and included human interventional studies that assessed the effects of oral lycopene intake on FBG levels of participants ≥ 18 years of age. Three authors independently selected applicable studies and then assessed the study quality. Data were pooled as standardized mean difference (SMD) and analyzed by the random-effects model. Heterogeneity was assessed by I² statistics. A meta-analysis including 11 trial arms (n = 750) revealed a tendency towards a significant decrease in FBG level with not-important heterogeneity [SMD = −0.15 (95% CI: −0.31, 0.00), p = 0.05, I² = 9%]. Subgroup meta-analysis including two studies (n = 152) in type 2 diabetes patients revealed significantly decreased FBG levels with not-important heterogeneity [SMD = −0.37 (95% CI: −0.69, −0.05), p = 0.02, I² = 0%]. Most studies meeting the eligibility criteria had a moderate risk of bias. The funnel plot for FBG suggested an absence of publication bias. In conclusion, this systematic review and meta-analyses suggested that lycopene intake exerted an FBG-decreasing effect.

AIM: To investigate the effects of broccoli sprout extract (BSEx) on liver gene expression and acute liver injury in the rat. METHODS: First, the effects of BSEx on liver gene expression were examined. Male rats were divided into two groups. The Control group was fed the AIN-76 diet, and the BSEx group was fed the AIN-76 diet containing BSEx. After a 10-d feeding period, rats were sacrificed and their livers were used for DNA microarray and real-time reverse transcription-polymerase chain reaction (RT-PCR) analyses. Next, the effects of BSEx on acute liver injury were examined. In experiments using acute liver injury models, 1000 mg/kg acetaminophen (APAP) or 350 mg/kg D-galactosamine (D-GalN) was used to induce injury. These male rats were divided into four groups: Control, BSEx, Inducer (APAP or D-GalN), and Inducer+BSEx. The feeding regimens were identical for the two analyses. Twenty-four hours following APAP administration via p.o. or D-GalN administration via i.p., rats were sacrificed to determine serum aspartate transaminase (AST) and alanine transaminase (ALT) levels, hepatic glutathione (GSH) and thiobarbituric acid-reactive substances accumulation and glutathione-S-transferase (GST) activity. RESULTS: Microarray and real-time RT-PCR analyses revealed that BSEx upregulated the expression of genes related to detoxification and glutathione synthesis in normal rat liver. The levels of AST (70.91 ± 15.74 IU/mL vs 5614.41 ± 1997.83 IU/mL, P < 0.05) and ALT (11.78 ± 2.08 IU/mL vs 1297.71 ± 447.33 IU/mL, P < 0.05) were significantly suppressed in the APAP + BSEx group compared with the APAP group. The level of GSH (2.61 ± 0.75 nmol/g tissue vs 1.66 ± 0.59 nmol/g tissue, P < 0.05) and liver GST activity (93.19 ± 16.55 U/g tissue vs 51.90 ± 16.85 U/g tissue, P < 0.05) were significantly increased in the APAP + BSEx group compared with the APAP group. AST (4820.05 ± 3094.93 IU/mL vs 12465.63 ± 3223.97 IU/mL, P < 0.05) and ALT (1808.95 ± 1014.04 IU/mL vs 3936.46 ± 777.52 IU/mL, P < 0.05) levels were significantly suppressed in the D-GalN + BSEx group compared with the D-GalN group, but the levels of AST and ALT in the D-GalN + BSEx group were higher than those in the APAP + BSEx group. The level of GST activity was significantly increased in the D-GalN + BSEx group compared with the D-GalN group (98.04 ± 15.75 U/g tissue vs 53.15 ± 8.14 U/g tissue, P < 0.05). CONCLUSION: We demonstrated that BSEx protected the liver from various types of xenobiotic substances through induction of detoxification enzymes and glutathione synthesis.

Maintaining normal vascular endothelial function is important for preventing arteriosclerosis. Flow-mediated dilatation (FMD) is widely used to evaluate vascular endothelial function. Lycopene, a carotenoid abundant in tomatoes, has been reported to improve FMD, but its effect after 4 weeks of intake remains unclear. We conducted a randomized, placebo-controlled, double-blind, parallel-group trial to assess the effects of lycopene. Seventy-five healthy adults with borderline FMD (4–7%) were randomly assigned to placebo juice (0.7 mg lycopene), tomato juice (TJ, 15.0 mg), or high-lycopene tomato juice (HLTJ, 26.7 mg) groups. FMD, serum lycopene, oxidative stress markers (malondialdehyde, 8-hydroxy-2′-deoxyguanosine, 8-iso-prostaglandin F2α), and nitrogen oxide concentrations were measured every 4 weeks over a 12-week intervention. The participants analyzed included 23 (placebo), 25 (TJ), and 24 (HLTJ). Data were analyzed using a linear mixed effects model adjusting for baseline covariates and a post hoc Dunnett's test with Bonferroni correction for intergroup comparisons. At week 12, FMD was significantly higher in the TJ (6.1 ± 0.5%, p < 0.001) and HLTJ groups (7.0 ± 0.7%, p < 0.001) than in the placebo group (5.4 ± 0.6%). In the HLTJ group, FMD at weeks 4 (6.2 ± 1.0%, p < 0.001) and 8 (6.7 ± 0.7%, p < 0.001) was significantly higher than in the placebo group (5.4 ± 0.9% and 5.3 ± 0.6%, respectively). Serum lycopene concentrations were significantly increased in TJ and HLTJ groups than in the placebo group. No significant differences were observed in oxidative stress or nitrogen oxide levels. These findings suggest that lycopene intake improves vascular endothelial function, though the mechanism remains unclear. Trial registration: UMIN000051176.

Introduction: Metabolic syndrome (MetS) is a major health concern in Vietnam. Although carotenoids have been suggested to suppress MetS, there has been no research on the relationship between carotenoid levels in the body and MetS risk in Vietnam. Therefore, this study clarified the relationship between skin carotenoid levels and markers related to MetS in Vietnamese adults using Vegecheck®, a device for non-invasively measuring skin carotenoid levels. Methods: This cross-sectional study included 300 participants, and data were collected at the Dr. Binh TeleClinic, a hospital in Hanoi, Vietnam. Data on skin carotenoid levels, anthropometric parameters (height, weight, and body fat percentage), blood pressure, and blood parameters (glucose, triglyceride, and high- and low-density lipoprotein cholesterol levels) were collected. MetS risk counts were defined as the number of MetS components in accordance with international standards for MetS. Additionally, participants answered questions regarding their attributes and lifestyles using a simple questionnaire. Results: After excluding 22 participants with missing data, 278 participants were included in the analysis. The average skin carotenoid levels in all participants were 5.41 ± 1.31, 4.99 ± 1.10 in men, and 5.67 ± 1.37 in women. Higher skin carotenoid levels were associated with lower MetS risk counts. The odds ratio (OR), with 95% confidence interval (CI), was 0.767 [0.645–0.910] ( p = 0.003). Skin carotenoid levels are significantly negatively associated with body weight, body mass index, blood glucose, and triglyceride levels. The estimated regression coefficient and 95% CI after multivariable adjustment were −0.016 [−0.0301, −0.0011] ( p = 0.034), −0.018 [−0.0305, −0.0045] ( p = 0.008), −0.043 [−0.0686, −0.0177] ( p < 0.001), and −0.090 [−0.1429, −0.0374] ( p < 0.001), respectively. Conclusion: This study indicates a relationship between carotenoid levels and MetS risk in Vietnamese individuals, although a causal relationship between carotenoid intake and MetS could not be established. This study has some limitations, such as the influence of unknown confounding factors and selection bias, and the unclearness of individual carotenoids’ effects. Future observational and intervention studies taking these limitations into account are required. Clinical trial registration: ClinicalTrials.gov , identifier NCT06271070.

Background/Objectives: Vascular endothelial dysfunction is an early marker of cardiovascular disease. Lycopene, a naturally red carotenoid with strong antioxidant activity, may improve vascular endothelial function. This systematic review and meta-analysis examined lycopene’s effects on vascular endothelial function in healthy adults in the context of cardiovascular risk assessment. Methods: In June 2026, we searched four literature databases (Ichushi-Web, PubMed, Cochrane Central Register of Controlled Trials, and Global Index Medicus), three clinical trial registries (International Clinical Trial Registry Platform, ClinicalTrials.gov, and University Hospital Medical Information Network Clinical Trials Registry), and notification information for Foods with Function Claims, using peer-reviewed search strategies. We extracted human intervention studies assessing oral lycopene intake and vascular endothelial function. Two authors independently selected eligible studies and assessed the risk of bias. Data were pooled as mean differences (MDs) and analyzed using a random-effects model. The protocol was registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN000058348). Results: Six studies were included in this systematic review. A meta-analysis of four continuous (≥7 days) lycopene-containing product intake studies measuring flow-mediated dilation (FMD) (n = 182) revealed a significant increase in FMD (MD = 1.36, 95% confidence interval: 0.20, 2.51, p = 0.02). The certainty of the evidence across the four studies was limited and moderate. One study not included in the meta-analysis showed that 15 mg of lycopene intake for 8 weeks significantly increased the reactive hyperemia peripheral arterial tonometry index. Conclusions: This systematic review/meta-analysis with limited and moderate certainty evidence suggests that the continuous intake of lycopene-containing products may have beneficial effects on vascular endothelial function in healthy adults. However, the findings were derived from a small-scale meta-analysis in which the result was no longer statistically significant after the exclusion of one study.