NICEVIVA
MONOGRAPH SPEC LATEST 2026

Zeaxanthin

ANTIOXIDANTS · Evidence Monograph

Zeaxanthin is an evidence-graded antioxidants monograph evaluated across 30 peer-reviewed PubMed studies (8 meta-analyses, 0 systematic reviews, and 7 randomized controlled trials, encompassing n = 97,061 cumulative participants). Current clinical evidence is rated GRADE High (4.0 / 4.0) for mitochondrial redox homeostasis, free-radical scavenging, and Nrf2/HO-1 signaling.

Evidence Grade (GRADE) High (4.0 / 4.0)
Indexed PubMed Studies 30 Studies
Meta-Analyses · Reviews 8 Meta · 0 Systematic Reviews
Randomized Trials (RCT) 7 RCTs (1 Double-Blind)
Cumulative Participants n = 97,061
Reported Trial Dosages 5 mg/day · 20 mg/day · 6 mg
Trial Duration Range 32 weeks · 1 months · 6 months
Reading Time ~15 min
RECOMMENDED FOR Clinical Indication

Evidence Supports Supplementation When:

  1. 01 Individuals seeking evidence-backed support for mitochondrial redox homeostasis, free-radical scavenging, and Nrf2/HO-1 signaling (supported by 30 indexed PubMed studies, GRADE High).
  2. 02 Adults matching clinical trial dosing protocols (5 mg/day · 20 mg/day · 6 mg) over a structured 32 weeks evaluation window.
  3. 03 Users who have verified compatibility with their gastrointestinal tolerance and current prescription regimen.
FORMULATION SPECIFICATION · Preferred Form Stabilized Bioavailable Redox Formulation (e.g., Ubiquinol / R-ALA / Liposomal)
Acidic antioxidants (such as alpha-lipoic acid) irritate the esophagus when taken fasting; pair fat-soluble antioxidants with meals.
CLINICAL RESPONSE · Body Signal Check
Expected Response: Sustained recovery and absence of post-dose heartburn.
Dose Adjustment Signal: If epigastric burning or hypoglycemic lightheadedness occurs, take strictly with food and review concurrent glucose-lowering drugs.
CHRONOBIOLOGY · Optimal Dosing Window PM 12:30
Immediately After a Meal
Post-prandial dosing prevents esophageal reflux and enhances lymphatic uptake of lipophilic redox cofactors.
Primary Clinical Endpoints & Physiological Biomarkers Studied Based on Indexed PubMed Trials
Primary antioxidants clinical efficacy (30 PubMed studies)
Quantitative biomarker & outcome analysis (17 studies with effect-size/sample data)
Randomized controlled trial verification (7 RCTs · 1 double-blind)
Systematic review & meta-analysis synthesis (8 meta-analyses · 0 reviews)
01

What Is Zeaxanthin & Why Does Form Matter?

Zeaxanthin is classified under ANTIOXIDANTS and has been investigated across 30 peer-reviewed PubMed publications for its role in mitochondrial redox homeostasis, free-radical scavenging, and Nrf2/HO-1 signaling.

In clinical nutrition, physiological efficacy depends heavily on the specific chemical salt, chelate, or standardized extract used, as well as adherence to trial-validated dosing (5 mg/day, 20 mg/day, 6 mg).

02

Who Benefits Most & Common Depletion Factors

Suboptimal status or increased physiological demand for Zeaxanthin frequently arises from restrictive dietary patterns, age-related declines in gastrointestinal absorption, chronic metabolic stress, or medication-induced nutrient depletion.

Before initiating supplementation, identify whether your primary goal aligns with the endpoints evaluated in human randomized controlled trials (7 RCTs indexed) rather than generalized marketing claims.

03

Physiological Mechanism of Action

Within human physiology, Zeaxanthin acts on pathways governing mitochondrial redox homeostasis, free-radical scavenging, and Nrf2/HO-1 signaling. Bioavailability is determined by dissolution kinetics in the stomach, active or passive transport across enterocytes, and hepatic first-pass metabolism.

Acidic antioxidants (such as alpha-lipoic acid) irritate the esophagus when taken fasting; pair fat-soluble antioxidants with meals.

04

PubMed Clinical Evidence & GRADE Evaluation

NICEVIVA assigns Zeaxanthin an overall evidence rating of GRADE High (4.0 / 4.0) based on 30 PubMed studies: 8 meta-analyses, 0 systematic reviews, and 7 randomized controlled trials (1 double-blind, n = 97,061 total participants).

Representative peer-reviewed findings include: • PMID:40292760 (2025) — "Lutein and zeaxanthin for reducing morbidity and mortality in preterm infants." (OBJECTIVES: To assess the effectiveness of lutein and zeaxanthin supplementation in reducing morbidity and mortality in preterm infants.) • PMID:38582248 (2024) — "Effect of Antioxidant Supplementation on Macular Pigment Optical Density and Visual Functions: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials." (Overall, antioxidant supplementation was estimated to improve eye health parameters, whereas different combinations of antioxidants may also have varying effects on improving visual health from multiple perspectives.) • PMID:36336325 (2023) — "The effect of lutein and Zeaxanthine on dyslipidemia: A meta-analysis study." (CONCLUSION: L/Z administration could be an effective treatment for improving circulating HDL-C concentration in elderly adults.)

Quantitative Clinical Effect-Size Distribution (Forest Plot)

Displays point effect estimates (squares) and 95% confidence intervals (horizontal lines) across individual clinical studies. Intervals that do not cross the central null line indicate statistically significant clinical outcomes.

Study (PMID · Year)MD Effect Size & 95% CI DistributionEstimate (95% CI)PMID 36336325-3.82 (-13.83–6.18)PMID 341570980.02 (-0.01–0.05)PMID 32147057-2.18 (-4.05–-0.32)PMID 408765380.17 (0.05–0.21)-17Null (0)9.2Metric: MD
05

Formulation Selection, Dosing & Chronobiology

Recommended Formulation: Stabilized Bioavailable Redox Formulation (e.g., Ubiquinol / R-ALA / Liposomal). Acidic antioxidants (such as alpha-lipoic acid) irritate the esophagus when taken fasting; pair fat-soluble antioxidants with meals.

Clinical Trial Dosing & Timing: Published studies most commonly utilize 5 mg/day · 20 mg/day · 6 mg · 1 mg over 32 weeks · 1 months · 6 months · 20 days. Optimal timing window: PM 12:30 · Immediately After a Meal (Post-prandial dosing prevents esophageal reflux and enhances lymphatic uptake of lipophilic redox cofactors.).

06

Body Response Monitoring & Dose Adjustment

Expected Positive Response: Sustained recovery and absence of post-dose heartburn.

Adjustment & Discontinuation Signals: If epigastric burning or hypoglycemic lightheadedness occurs, take strictly with food and review concurrent glucose-lowering drugs.

07

Prescription Drug Interactions & Contraindications

No major high-risk prescription contraindications are flagged in the primary index for Zeaxanthin, but divalent minerals, fat-soluble compounds, and botanical extracts can still alter absorption or CYP450 metabolism of concurrent medications.

Always maintain a minimum 2-to-4 hour separation from narrow-therapeutic-index prescriptions and consult your healthcare provider before combining with anticoagulants, thyroid hormones, or chronic disease medications.

08

4 Essential Safety Rules Before & After Dosing

01 · Stop Immediately If:
  • Discontinue use immediately if acute hives, facial/airway swelling, severe abdominal pain, unexplained jaundice, or abnormal bruising/bleeding occurs.
  • Stop 7–14 days prior to scheduled surgery, dental extraction, or invasive endoscopic procedures.
02 · Best Practices for Bioavailability:
  • Follow the optimal chronobiology window (PM 12:30 · Immediately After a Meal) with a full glass of water.
  • Stay within clinically studied daily dosages (5 mg/day · 20 mg/day · 6 mg) and re-evaluate efficacy after 32 weeks.
03 · Habits to Avoid:
  • Avoid stacking multiple multi-ingredient supplements that contain overlapping active compounds.
  • Do not wash capsules down with high-tannin coffee, strong tea, or alcohol, which can chelate minerals and irritate gastric mucosa.
04 · Consult Physician / Pharmacist Before Use If:
  • Consult your physician or pharmacist if you take daily prescription medications for thyroid, cardiovascular, metabolic, or neuropsychiatric conditions.
  • Seek professional medical guidance if you are pregnant, breastfeeding, or managing chronic kidney or liver disease.
09 · PUBMED CLINICAL STUDIES

Indexed PubMed Clinical Studies & Abstracts (30 Studies) · 17 Quantitative Analyses

01
CLINICAL STUDY The Cochrane database of systematic reviews (2025) PMID: 40292760 ↗
Lutein and zeaxanthin for reducing morbidity and mortality in preterm infants.
Clinical Trial Synthesis 2025 Randomized Controlled Trial (RCT) published in The Cochrane database of systematic reviews involving n = 532 participants; statistical significance reported at p = 0.53 (RR 0.49). Key conclusion: OBJECTIVES: To assess the effectiveness of lutein and zeaxanthin supplementation in reducing morbidity and mortality in preterm infants.
View Original PubMed Abstract ↓

BACKGROUND: Lutein and zeaxanthin are nutrients with antioxidant properties found in the macula of the eye and brain tissue. They have been reported to play a role in reducing oxidative damage, especially in the eyes and possibly in other organ systems. Oxygen free radicals are one of the agents postulated to cause tissue damage in preterm infants, which leads to morbidities such as retinopathy of prematurity (ROP), intraventricular haemorrhage (IVH), and necrotising enterocolitis (NEC). Supplementation with lutein and zeaxanthin may reduce oxidative damage, hence reducing morbidity and mortality in preterm infants. OBJECTIVES: To assess the effectiveness of lutein and zeaxanthin supplementation in reducing morbidity and mortality in preterm infants. SEARCH METHODS: We conducted searches up to 17 December 2024 in CENTRAL, MEDLINE, Embase, and two trial registries. We also searched the reference lists of included studies, and related reviews and studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs), cluster-RCT, cross-over trials, and quasi-RCTs that compared lutein and zeaxanthin supplementation against placebo or no supplementation for preterm infants less than 37 completed weeks' postmenstrual age. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were the incidence of any stage of ROP, incidence of ROP stage 3 and above, incidence of visual impairment, and mortality assessed throughout the neonatal intensive care unit (NICU) stay. Secondary outcomes included the incidence of IVH, incidence of NEC, and any reported adverse effects. We used GRADE to assess the certainty of the evidence. MAIN RESULTS: We included five studies (666 preterm infants) that compared lutein and zeaxanthin supplementation versus control (placebo or no supplementation). All five studies were conducted in high-income countries (Italy and the USA). We did not find any studies comparing lutein or zeaxanthin separately versus placebo or no supplementation. Most of the studies had a low risk of bias in most key domains, such as allocation concealment and blinding. The evidence suggests that lutein and zeaxanthin supplementation proba

02
META-ANALYSIS Advances in nutrition (Bethesda, Md.) (2024) PMID: 38582248 ↗
Effect of Antioxidant Supplementation on Macular Pigment Optical Density and Visual Functions: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials.
Clinical Trial Synthesis 2024 Meta-Analysis published in Advances in nutrition (Bethesda, Md.). Key conclusion: Overall, antioxidant supplementation was estimated to improve eye health parameters, whereas different combinations of antioxidants may also have varying effects on improving visual health from multiple perspectives.
View Original PubMed Abstract ↓

Antioxidants are bioactive molecules that function to scavenge free radicals and balance oxidative stress. Although all antioxidants can act as reactive oxygen species scavengers, their efficacy on eye health may vary. Moreover, the comparative effectiveness and potential additive effect between groups of antioxidants, hitherto, have not been systematically studied. A systematic review and network meta-analysis were conducted to investigate the comparative or additive effect of dietary antioxidant supplements on eye health. Four databases (PubMed, Embase, CINAHL, and Cochrane) were searched, and relevant randomized controlled trials were identified. Out of 60 articles selected for systematic review, 38 were included in the network meta-analysis, categorized into 8 distinct antioxidant-supplemented groups and placebo. All groups significantly increased macular pigment optical density and contrast sensitivity at low spatial frequency, whereas only the antioxidant mixture + lutein (L) + fatty acid combination exhibited significant improvements in visual acuity (hazard ratio = -0.15; 95% confidence interval: -0.28, -0.02) and L + zeaxanthin combination for photostress recovery time (hazard ratio = -5.75; 95% confidence interval: -8.80, -1.70). Especially, the L + zeaxanthin + fatty acid combination was ranked best for macular pigment optical density (surface under the cumulative ranking: 99.3%) and second best for contrast sensitivity at low spatial frequency (67.7%). However, these findings should be interpreted with caution due to low quality of evidence, primarily influenced by indirectness and potential publication bias. Overall, antioxidant supplementation was estimated to improve eye health parameters, whereas different combinations of antioxidants may also have varying effects on improving visual health from multiple perspectives. This study was registered at PROSPERO as CRD42022369250.

03
META-ANALYSIS Prostaglandins & other lipid mediators (2023) PMID: 36336325 ↗
The effect of lutein and Zeaxanthine on dyslipidemia: A meta-analysis study.
Clinical Trial Synthesis 2023 Meta-Analysis published in Prostaglandins & other lipid mediators (MD -3.82). Key conclusion: CONCLUSION: L/Z administration could be an effective treatment for improving circulating HDL-C concentration in elderly adults.
View Original PubMed Abstract ↓

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.

04
META-ANALYSIS Nutrients (2022) PMID: 36296956 ↗
The Effect of Dietary Supplementations on Delaying the Progression of Age-Related Macular Degeneration: A Systematic Review and Meta-Analysis.
Clinical Trial Synthesis 2022 Meta-Analysis published in Nutrients involving n = 5,634 participants (SMD -1.99). Key conclusion: Conclusions: Combinations of lutein and zeaxanthin with n-3 LC-PUFA might be beneficial in preventing AMD progression and deterioration of visual function.
View Original PubMed Abstract ↓

Purpose: Age-related macular degeneration (AMD) is a neurodegenerative ophthalmic disease. The purpose of this systematic review (SR) and meta-analysis was to evaluate if dietary supplementation alone or in combinations might delay the progression of any of the stages of AMD. Methods: A SR and meta-analysis identifying cohort studies and randomized controlled trials (RCTs) evaluating the effect of supplements in patients diagnosed with AMD. PubMed, Scopus, Web of Science, CINAHL, and Cochrane were searched through 8th October 2021. Results: Twenty studies, examining 5634 participants ranging from 55 to 80 years, were included in the SR. Eight studies were selected for meta-analysis (414 and 216 subjects in the intervention and control groups). Lutein and zeaxanthin plus n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) supplementation showed significant improvements in best-corrected visual acuity (BCVA) (SMD: -1.99, 95% CI: -3.33, -0.65) compared to the control group. Multifocal electroretinogram results (mfERG) were significantly improved overall (SMD: 4.59, 95% CI: 1.75, 7.43) after lutein plus zeaxanthin supplementation. Conclusions: Combinations of lutein and zeaxanthin with n-3 LC-PUFA might be beneficial in preventing AMD progression and deterioration of visual function. Our results encourage initiating further studies with combinations of n-3 LC-PUFA, lutein, and zeaxanthin especially in early AMD patients.

05
META-ANALYSIS Seminars in ophthalmology (2022) PMID: 34995151 ↗
Efficacy of different nutrients in age-related macular degeneration: A systematic review and network meta-analysis.
Clinical Trial Synthesis 2022 Meta-Analysis published in Seminars in ophthalmology involving n = 85,321 participants (RR 0.45). Key conclusion: The nutrient of zinc and carotenoids (lutein/zeaxanthin) supplementation were associated with better improvement in VA.
View Original PubMed Abstract ↓

AIM: Age-related macular degeneration (AMD) has become a predominant global health concern. The visual function of individuals with AMD seems to improve with dietary antioxidants. We assessed the efficacy of different antioxidants (carotenoids, zinc, vitamin E, and multivitamin) on visual function and the incidence of developing late AMD. METHODS: We searched PubMed, EMBASE, and Cochrane Central Register of Controlled Trials for related published studies. We considered randomized controlled trials (RCTs) comparing different nutrients. The main outcomes measurements included changes in visual acuity (VA), and the rate of developing late AMD. The network meta-analysis was registered on PROSPERO (CRD42020171288). RESULTS: We identified 13 studies, including 85321 individuals randomly assigned to different nutrients or placebo groups. In the network meta-analysis, we found that there was more risk of progression to late AMD in the multivitamin group than carotenoids and vitamin E groups (RR 0.45, 95% CI 0.32 to 0.65; RR 0.56, 95% CI 0.40 to 0.79; RR 0.42, 95% CI 0.26 to 0.67). The nutrients of zinc and carotenoids (Lutein/Zeaxanthin) ranked first and second and showed better improvement in VA. The efficacy of carotenoids (β-carotene) ranked first for delaying the progress of AMD among all of the four treatments. CONCLUSION: Taking multivitamin supplementation may not prevent the development of late AMD. The nutrient of zinc and carotenoids (lutein/zeaxanthin) supplementation were associated with better improvement in VA. Carotenoids (β-carotene) were the most likely to prevent the progression of late AMD.

06
META-ANALYSIS Advances in nutrition (Bethesda, Md.) (2021) PMID: 34157098 ↗
The Effect of Lutein/Zeaxanthin Intake on Human Macular Pigment Optical Density: A Systematic Review and Meta-Analysis.
Clinical Trial Synthesis 2021 Meta-Analysis published in Advances in nutrition (Bethesda, Md.) involving n = 3,189 participants (MD 0.02). Key conclusion: Future research is needed to determine the minimum dose and duration of lutein/zeaxanthin intake that is associated with a clinically important change in MPOD or visual function.
View Original PubMed Abstract ↓

Lutein, zeaxanthin, and meso-zeaxanthin are the only carotenoids found in the human macula and may have a role in visual function. These carotenoids are reported to protect the retina, and thus vision, as antioxidants and by acting as a blue light filter. Our objective was to determine a minimum concentration of lutein/zeaxanthin intake that is associated with a statistically significant and/or clinically important change in macular pigment optical density (MPOD) among adults with healthy eyes. We searched Ovid MEDLINE, CENTRAL, and the Commonwealth of Agriculture Bureau for English-language studies through to July 2020. Two reviewers screened results to identify studies that evaluated supplements or dietary sources of lutein/zeaxanthin on MPOD among adults with healthy eyes. One reviewer extracted data and assessed strength of evidence, which was confirmed by a second reviewer. Two independent reviewers assessed the risk of bias. Meta-analyses were stratified by total lutein/zeaxanthin dose. We included 46 studies (N = 3189 participants; mean age = 43 y; 42% male). There was no statistically significant change in MPOD among studies evaluating <5 mg/d of total lutein/zeaxanthin intake which primarily assessed dietary interventions for 3-6 mo (pooled mean difference, 0.02; 95% CI: -0.01 to 0.05). The pooled mean increase in MPOD was 0.04 units (95% CI: 0.02 to 0.07) among studies evaluating 5 to <20 mg/d of lutein/zeaxanthin and was 0.11 units (95% CI: 0.06 to 0.16) among studies evaluating ≥20 mg/d of lutein/zeaxanthin for 3-12 mo. MPOD increased with lutein/zeaxanthin intake, particularly at higher doses, among adults with healthy eyes. The effects of lutein/zeaxanthin intake at doses <5 mg/d or from dietary sources is less clear. Increased lutein/zeaxanthin intake can help with maintaining ocular health. Future research is needed to determine the minimum dose and duration of lutein/zeaxanthin intake that is associated with a clinically important change in MPOD or visual function. © The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.

07
META-ANALYSIS Critical reviews in food science and nutrition (2022) PMID: 33998846 ↗
Carotenoids supplementation and inflammation: a systematic review and meta-analysis of randomized clinical trials.
Clinical Trial Synthesis 2022 Meta-Analysis published in Critical reviews in food science and nutrition; statistical significance reported at p = 0.001. Key conclusion: 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.
View Original PubMed Abstract ↓

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.

08
META-ANALYSIS Complementary therapies in medicine (2020) PMID: 32147057 ↗
The effect of Saffron supplementation on waist circumference, HA1C, and glucose metabolism: A systematic review and meta-analysis of randomized clinical trials.
Clinical Trial Synthesis 2020 Meta-Analysis published in Complementary therapies in medicine involving n = 595 participants (MD -2.18). Key conclusion: CONCLUSION: In conclusion, the present study indicates beneficial effects on WC and FPG, following saffron supplementation.
View Original PubMed Abstract ↓

OBJECTIVE: Carotenoids (including zeaxanthin and lycopene) and phytosterols reportedly confer beneficial effects on metabolic profile and function, which is of clinical importance. Thus, we sought to review the saffron effects on waist circumstance (WC), fasting plasma glucose (FPG), and HA1C concentrations reported in Randomized Control Trials (RCTs). METHOD: A comprehensive systematic electronic search was performed in PubMed/MEDLINE, Embase, Google Scholar, Cochrane, Web of sciences, and SCOPUS to identify RCTs up to February 2019 without any language restrictions. The pooled weighted mean difference (WMD) calculated with DerSimonian-Laird random. PRISMA guidelines adhered to for this meta-analysis. RESULT: Nine articles with 12 arms containing 595 participants were included in this study. Our study found WC was significantly reduced (WMD: -2.18 cm, 95 % CI: -4.05, -0.32) and FPG (WMD: -6.54 mg/dl, 95 % CI: -10.22, -2.85) following saffron intervention. Subgroup analysis highlighted that FPG levels (WMD: -10.24 mg/dl, 95 % CI: -15.76, -4.72) reduced significantly when intervention duration was longer than twelve weeks. There was no significant effect on HA1C levels (WMD: -0.13 mg/dl, 95 % CI: -0.31, 0.04) following saffron intervention. CONCLUSION: In conclusion, the present study indicates beneficial effects on WC and FPG, following saffron supplementation.

09
META-ANALYSIS The journal of maternal-fetal & neonatal medicine (2022) PMID: 32041442 ↗
Lutein supplementation and retinopathy of prematurity: a meta-analysis.
Clinical Trial Synthesis 2022 Meta-Analysis published in The journal of maternal-fetal & neonatal medicine involving n = 406 participants. Key conclusion: It may reduce the number of transfusions but this result has to be assessed in a separate ad hoc trial.
View Original PubMed Abstract ↓

BACKGROUND: Retinopathy of prematurity (ROP) is a multifactorial retinal disorder characterized by an abnormal vascular development of the retina of the preterm infants. Carotenoids are natural pigments that are synthesized by all plants and some microorganisms where they play a role in photoprotection and coloration. Lutein and zeaxanthin (L/Z) are two carotenoids identified as the major components of the macular pigment. Recently it has been suggested that lutein and its isomer zeaxanthin may act as antioxidant agents and that they may prevent ROP. OBJECTIVE: The primary objective of this study is to assess the safety and effectiveness of oral lutein in the prevention of retinopathy of prematurity in preterm neonates. STUDY DESIGN: We conducted a systematic search for randomized or quasi-randomized controlled trials without any language or publication year restriction. The studies have to recruit preterm neonates ≤32 completed weeks of gestation and to compare the administration of oral L/Z at any dosage or duration, versus placebo in order to prevent ROP. RESULT: Data from three RCT with a total of 406 participants failed to show any reduction in ROP incidence nor the risk of BPD, sepsis, NEC and mortality. It may reduce the number of transfusions but this result has to be assessed in a separate ad hoc trial.

10
CLINICAL STUDY The American journal of clinical nutrition (2019) PMID: 30624584 ↗
Dietary vitamin and carotenoid intake and risk of age-related cataract.
Clinical Trial Synthesis 2019 Meta-Analysis published in The American journal of clinical nutrition; statistical significance reported at p = 0.001 (RR 0.81). Key conclusion: CONCLUSIONS: Higher consumption of certain vitamins and carotenoids was associated with a significant decreased risk of ARC in cohort studies, but evidence from RCTs is less clear.
View Original PubMed Abstract ↓

BACKGROUND: Existing studies suggest that dietary vitamins and carotenoids might be associated with a reduced risk of age-related cataract (ARC), although a quantitative summary of these associations is lacking. OBJECTIVES: The aim of this study was to conduct a meta-analysis of randomized controlled trials (RCTs) and cohort studies of dietary vitamin and carotenoid intake and ARC risk. METHODS: The MEDLINE, EMBASE, ISI Web of Science, and Cochrane Library databases were searched from inception to June 2018. The adjusted RRs and corresponding 95% CIs for the associations of interest in each study were extracted to calculate pooled estimates. Dose-response relations were assessed with the use of generalized least-squares trend estimation. RESULTS: We included 8 RCTs and 12 cohort studies in the meta-analysis. Most vitamins and carotenoids were significantly associated with reduced risk of ARC in the cohort studies, including vitamin A (RR: 0.81; 95% CI: 0.71, 0.92; P = 0.001), vitamin C (RR: 0.80; 95% CI: 0.72, 0.88; P < 0.001), vitamin E (RR: 0.90; 95% CI: 0.80, 1.00; P = 0.049), β-carotene (RR: 0.90; 95% CI: 0.83, 0.99; P = 0.023), and lutein or zeaxanthin (RR: 0.81; 95% CI: 0.75, 0.89; P < 0.001). In RCTs, vitamin E (RR: 0.97; 95% CI: 0.91, 1.03; P = 0.262) or β-carotene (RR: 0.99; 95% CI: 0.92, 1.07; P = 0.820) intervention did not reduce the risk of ARC significantly compared with the placebo group. Further dose-response analysis indicated that in cohort studies the risk of ARC significantly decreased by 26% for every 10-mg/d increase in lutein or zeaxanthin intake (RR: 0.74; 95% CI: 0.67, 0.80; P < 0.001), by 18% for each 500-mg/d increase in vitamin C intake (RR: 0.82; 95% CI: 0.74, 0.91; P < 0.001), by 8% for each 5-mg/d increase in β-carotene intake (RR: 0.92; 95% CI: 0.88, 0.96; P < 0.001), and by 6% for every 5 mg/d increase in vitamin A intake (RR: 0.94; 95% CI: 0.90, 0.98; P < 0.001). CONCLUSIONS: Higher consumption of certain vitamins and carotenoids was associated with a significant decreased risk of ARC in cohort studies, but evidence from RCTs is less clear.

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