Lutein supplementation combined with a low-calorie diet in middle-aged obese individuals: effects on anthropometric indices, body composition and metabolic parameters

An Overview on the Effects of Some Carotenoids on Health: Lutein and Zeaxanthin

PURPOSE OF REVIEW

In this review, the chemical properties, nutritional sources, absorption mechanisms, metabolism, biosynthesis and promising health-related benefits of lutein and zeaxanthin were emphasized and some recommendations for the future studies are suggested.

RECENT FINDINGS

Lutein and zeaxanthin are phytochemical compounds in the carotenoid group and are synthesised only by plants. All mammals get lutein and zeaxanthin into their bodies by consuming plant-based foods. Especially leafy green vegetables, broccoli, pumpkin, cabbage, spinach and egg yolk are rich in lutein and zeaxanthin. Lutein and zeaxanthin have potential health effects by preventing free radical formation, exhibiting protective properties against oxidative damage and reducing oxidative stress. These compounds have neuroprotective, cardioprotective, ophthalmological, antioxidant, anti-inflammatory, anti-cancer, anti-osteoporosis, anti-diabetic, anti-obesity, and antimicrobial effects. The preventive properties of lutein and zeaxanthin against numerous diseases have attracted attention recently. Further clinical trials with large samples are needed to make generalisations in the prevention and treatment of diseases and to determine the appropriate doses and forms of lutein and zeaxanthin.

Effects of carotenoid supplementation on glycemic control: a systematic review and meta-analysis of randomized clinical trials

OBJECTIVES

We conducted a systematic review and meta-analysis to assess the effects of carotenoid supplementation on glycemic indices, and the certainty of evidence.

METHODS

A systematic literature search in PubMed, SCOPUS, ISI-Web of Science, and Cochrane Library was conducted from inception up to Jun 17, 2024. Randomized controlled trials (RCTs) investigating the effect of carotenoid supplementation on circulating glycemic parameters were included. Records were excluded when studies reported the effect of co-interventions with other nutrients, did not provide mean differences (MDs) and standard deviations (SD) for outcomes, or administered whole food rather than supplements of carotenoids. Summary mean differences (MDs) and 95% CI between intervention and control groups were estimated using a random-effects model. The risk of bias of the included studies was assessed using the Risk of Bias 2.0 (RoB 2.0) tool.

RESULTS

Overall, 36 publications with 45 estimated effect sizes were included in the meta-analyses. The overall findings showed an improvement in fasting blood glucose (FBG) (MD = -4.54 mg/dl; 95% CI: -5.9, -3.2; n = 45), and hemoglobin A1C (HbA1C) (MD = -0.25% (95% CI: -0.4, -0.11; n = 22) in the intervention group in comparison with the control group. Moreover, in individuals with type 2 diabetes (T2D), interventions with astaxanthin and fucoxanthin led to a reduction in FBG by 4.36 mg/dl (95% CI: -6.13, -2.6; n = 10). The findings also showed that the intervention with crocin reduced FBG levels by 13.5 mg/dl (95% CI: -15.5, -7.8; n = 5), and HbA1C by 0.55% (95% CI: -0.77, -0.34; n = 5) in individuals with T2D. However, the certainty of evidence was very low.

CONCLUSION

Carotenoid's supplementation improved glycemic parameters especially in people with T2D. However. the certainty of evidence was very low, mainly due to small sample size, and indirectness. Therefore, no specific recommendations can be provided at present and well-designed RCTs are required. REGISTRY URL: https://www.crd.york.ac.uk/PROSPERO/ REGISTRY NUMBER: CRD42021285084 REGISTRY AND REGISTRY NUMBER FOR SYSTEMATIC REVIEWS OR META-ANALYSES: PROSPERO ID: CRD42021285084.

A comprehensive insight into the molecular effect of theobromine on cardiovascular-related risk factors: A systematic review of in vitro and in vivo studies

Theobromine may have beneficial effects on cardiovascular risk factors. This study aimed to find molecular effects of theobromine on lipid profile, glycemic status, inflammatory factors, and vascular function through a comprehensive assessment of all in vitro and in vivo studies. The search process was started at 18 July 2022. Databases including PubMed, Scopus, and Web of Science were searched to find all articles published up to 18 July 2022. Nineteen studies were included in this study. In vitro studies showed the improving effects of theobromine on inflammatory markers. Of four animal studies assessing the effect of theobromine on inflammatory markers, two reported favorable effects. Among five animal studies assessing the effects of theobromine on lipid profile, three reported improving effects on either triglyceride, total cholesterol, low- or high-density lipoprotein cholesterol. Of the three human studies, two revealed that theobromine had improving effects on lipid profile. A favorable effect of theobromine on augmentation index was also reported in two RCTs. The results for other outcomes were inconclusive. Theobromine may have favorable effects on inflammatory factors, lipid profile, and vascular function markers. However, studies with a longer duration and lower, dietary-relevant doses are required for future confirmation.

The role of lutein-rich purple sweet potato leaf extract on the amelioration of diabetic retinopathy in streptozotocin-induced Sprague-Dawley rats

The objective of this study is to access the effect of purple sweet potato leaf (PSPL) extract on diabetic retinopathy (DR) of streptozotocin (STZ)-induced male Sprague-Dawley (SD) rats. In this study, rats were injected intraperitoneally with a single dose of 60 mg/kg STZ, and diabetes was confirmed on day 7. Rats were further divided into a few groups, which were then orally administered with one of the following treatments: 25 mg/kg of gliclazide (D25G), 200 mg/kg of PSPL extract (DT 200), and 400 mg/kg of PSPL extract (DT 400). However, the normal control (NS) and control group for diabetic (DNS) were given normal saline (NS) for 12 weeks. The results show that the treated group demonstrated a reduction in serum oral glucose tolerance test (OGTT) levels of DT 200 and DT 400, and an increase in the serum and retinal insulin levels, and restored oxidative stress markers in serum and retina on week 12. The PSPL extract exhibited protective effects in maintaining the kidney, liver, retina, and pancreas architecture in 400 mg/kg compared to the 200 mg/kg treated group and D25G, thereby restoring fully transparent lenses in diabetes-induced rats. In conclusion, 400 mg/kg PSPL is the most effective dose for the amelioration of STZ-induced DR pathology in male SD rats.

The effect of lutein and Zeaxanthine on dyslipidemia: A meta-analysis study

AIMS

The relationship between circulating Lutein and zeaxanthin (L/Z) concentrations, and plasma lipoproteins has been indicated by observational studies. However, the beneficial impact of L/Z administration on dyslipidemia are unclear. This meta-analysis aimed to investigate the effect of oral intake of L/Z on circulating total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), as well as high-density lipoprotein-cholesterol (HDL-C) levels.

METHODS

We electronically assessed all eligible interventional studies through different electronic databases, including PubMed, Scopus, ISI -Web of Science, and Cochrane library until Jun 2021. After identifying the quality of each included randomized controlled trials, they were evaluated by assessing the risk-difference between treatment and control groups by pooling available data on net change of serum LDL-C, HDL-C, and Cholesterol.

RESULTS

L/Z supplementation has null effect on circulating levels of TC (WMD: -3.82 95% CI: -13.83, 6.18; I-square: 85.2%), and LDL-C (WMD: -4.54; 95% CI: -11.5, 2.48; I-square: 83.9%). In contrast, L/Z treatment could significantly increase HDL-C levels in older adults (WMD: 4.06; 95% CI: 0.64, 7.48; I-square: 50.7%).

CONCLUSION

L/Z administration could be an effective treatment for improving circulating HDL-C concentration in elderly adults.

Natural phytochemicals prevent side effects in BRCA-mutated ovarian cancer and PARP inhibitor treatment

Ovarian cancer is among the most common malignant tumors in gynecology and is characterized by insidious onset, poor differentiation, high malignancy, and a high recurrence rate. Numerous studies have shown that poly ADP-ribose polymerase (PARP) inhibitors can improve progression-free survival (PFS) in patients with BRCA-mutated ovarian cancer. With the widespread use of BRCA mutation and PARP inhibitor (PARPi) combination therapy, the side effects associated with BRCA mutation and PARPi have garnered attention worldwide. Mutations in the BRCA gene increase KEAP1-NRF2 ubiquitination and reduce Nrf2 content and cellular antioxidant capacity, which subsequently produces side effects such as cardiovascular endothelial damage and atherosclerosis. PARPi has hematologic toxicity, producing thrombocytopenia, fatigue, nausea, and vomiting. These side effects not only reduce patients' quality of life, but also affect their survival. Studies have shown that natural phytochemicals, a class of compounds with antitumor potential, can effectively prevent and treat the side effects of chemotherapy. Herein, we reviewed the role of natural phytochemicals in disease prevention and treatment in recent years, including sulforaphane, lycopene, catechin, and curcumin, and found that these phytochemicals have significant alleviating effects on atherosclerosis, nausea, and vomiting. Moreover, these mechanisms of action significantly correlated with the side-effect-producing mechanisms of BRCA mutations and PARPi. In conclusion, natural phytochemicals may be effective in alleviating the side effects of BRCA mutant ovarian cancer cells and PARP inhibitors.

Anthocyanins and Carotenoids Characterization in Flowers and Leaves of Cyclamen Genotypes Linked with Bioactivities Using Multivariate Analysis Techniques

The present study was carried out to evaluate and compare in vitro antioxidant (2,2-diphenyl-1-picrylhydrazyl (DPPH), Trolox equivalent antioxidant capacity (TEAC), and ferric reducing antioxidant power (FRAP)), antimicrobial, anticancer activities, and the individual carotenoids and anthocyanins content of methanol extracts of the Cyclamen genotypes: Persian cyclamen accessions (Cyclamen persicum Mill.), sowbread (C. mirabile Hildebr.), and ivy-leaved cyclamen (C. hederifolium Mill.) aerial parts. The HPLC-PDA analysis revealed the presence of five individual carotenoids (i.e., neoxanthin, violaxanthin, lutein, β-carotene, and cis-β-carotene) as the main compounds in Cyclamen leaves, and the presence of seven individual anthocycanins (i.e., cyanidin 3,5-di-O-glucoside, peonidin-rutinoside, peonidin 3,5-di-O-glucoside, peonidin 3-O-glucoside, malvidin 3-O-glucoside, malvidin 3,5-di-O-glucoside, and malvidin-rutinoside) in Cyclamen flowers reported, hereby, for the first time. The highest phenolic content was found in the leaves of LC6, C. mirabile (46.32 ± 0.14 mg/g gallic acid equivalents [GAE]), and in the flowers of C. persicum Merengue Magenta (FC15) (58.63 ± 0.17 mg/g GAE), whereas the highest flavonoid content was reported in C. persicum Halios Falbala leaves, namely LC9 (54.90 ± 0.27 mg/g quercetin equivalents [QE]) and in flowers of C. persicum Victora (FC2) (77.87 ± 0.25 mg/g QE). The highest antioxidant activity in DPPH and FRAP assays was reported in C. persicum Dark Violet (LC1) and Victoria (LC2), whereas C. mirabile (LC6) had the highest activity in the TEAC assay. In flowers, high antioxidant activities in DPPH and TEAC were noticed in C. persicum Superserie Red (FC7) and Dark Violet (FC1), respectively, and Halios Falbala (FC9) exhibited the highest activity in the TEAC assay. Additionally, FC9 exhibited the highest antibacterial activity in almost all tested bacteria compared with the leaves extracts. Furthermore, the highest in vitro citotoxicity in MDA-MB-231 cells was noticed in C. hederifolium LC18 (56.71-69.35%) and FC18 (40.07-41.43%), with a lower effect against BJ cells demonstrating selective toxicity. The above findings, highlight the potential use of the Cyclamen flower and leaf extracts as significant anticancer agents along with their antioxidant and antimicrobial properties.

Carotenoids: Dietary Sources, Extraction, Encapsulation, Bioavailability, and Health Benefits-A Review of Recent Advancements

Natural carotenoids (CARs), viz. β-carotene, lutein, astaxanthin, bixin, norbixin, capsanthin, lycopene, canthaxanthin, β-Apo-8-carotenal, zeaxanthin, and β-apo-8-carotenal-ester, are being studied as potential candidates in fields such as food, feed, nutraceuticals, and cosmeceuticals. CAR research is advancing in the following three major fields: (1) CAR production from natural sources and optimization of its downstream processing; (2) encapsulation for enhanced physical and chemical properties; and (3) preclinical, clinical, and epidemiological studies of CARs' health benefits. This review critically discusses the recent developments in studies of the chemistry and antioxidant activity, marketing trends, dietary sources, extraction, bioaccessibility and bioavailability, encapsulation methods, dietary intake, and health benefits of CARs. Preclinical, clinical, and epidemiological studies on cancer, obesity, type 2 diabetes (T2D), cardiovascular diseases (CVD), osteoporosis, neurodegenerative disease, mental health, eye, and skin health are also discussed.

Comment on "The association between carotenoids and subjects with overweight or obesity: a systematic review and meta-analysis" by N. Yao, S. Yan, Y. Guo, H. Wang, X. Li, L. Wang, W. Hu, B. Li and W. Cui, Food Funct., 2021, 12, 4768

The association between carotenoids and subjects with overweight or obesity: reanalysis is needed.

Reply to the 'Comment on "The association between carotenoids and subjects with overweight or obesity: a systematic review and meta-analysis"' by N. Shokri-mashhadi and S. Saadat, Food Funct., 2021, 12, DOI: 10.1039/D1FO01617B

Here, we re-emphasize the purpose of our meta-analysis of the associations between carotenoids and subjects with excess body weight (Yao et al., 2021) and address some of the points raised in the commentary by Nafiseh Shokri-mashhadi and Saeed Saadat. The commentary focused on the methodological faults of our published meta-analysis research-but the research was rigorously conducted and scientifically sound, following strictly the relevant requirements of the Cochrane guidelines. Therefore, in the current reply, we included an elaboration and thorough discussion of the search strategy, inclusion and exclusion criteria, and tests of heterogeneity for the discussed meta-analysis in light of the comments made in the commentary. In conclusion, we believe that our study has made an essential contribution to the investigation of the significance of carotenoids in people with excess body weight.

Carotenoids supplementation and inflammation: a systematic review and meta-analysis of randomized clinical trials

The aim of this study was to perform a systematic review and meta-analysis on randomized controlled trials investigating the effects of carotenoids on selected inflammatory parameters. PubMed, SCOPUS, and Web of science were searched from inception until April 2021. The random-effect model was used to analyze data and the overall effect size was computed as weighted mean difference (WMD) and corresponding 95% of confidence interval (CI). A total of 26 trials with 35 effect sizes were included in this meta-analysis. The results indicated significant effects of carotenoids on C-reactive protein (CRP) (WMD: ‒0.54 mg/L, 95% CI: ‒0.71, ‒0.37, P < 0.001), and interleukin-6 (IL-6) (WMD: ‒0.54 pg/mL, 95% CI: ‒1.01, ‒0.06, P = 0.025), however the effect on tumor necrosis factor-alpha (TNF-α) was not significant (WMD: ‒0.97 pg/ml, 95% CI: ‒1.98, 0.03, P = 0.0.059). For the individual carotenoids, astaxanthin, (WMD: ‒0.30 mg/L, 95% CI: ‒0.51, ‒0.09, P = 0.005), lutein/zeaxanthin (WMD: ‒0.30 mg/L, 95% CI: ‒0.45, ‒0.15, P < 0.001), and β-cryptoxanthin (WMD: ‒0.35 mg/L, 95% CI: ‒0.54, ‒0.15, P < 0.001) significantly decreased CRP level. Also, only lycopene (WMD: ‒1.08 pg/ml, 95%CI: ‒2.03, ‒0.12, P = 0.027) led to a significant decrease in IL-6. The overall results supported possible protective effects of carotenoids on inflammatory biomarkers.