NICEVIVA
MONOGRAPH SPEC LATEST 2026

Zeaxanthin (4mg)

EYE HEALTH · Evidence Monograph

Zeaxanthin (4mg) is an evidence-graded eye health monograph evaluated across 30 peer-reviewed PubMed studies (3 meta-analyses, 5 systematic reviews, and 7 randomized controlled trials, encompassing n = 11,846 cumulative participants). Current clinical evidence is rated GRADE High (4.0 / 4.0) for targeted physiological homeostasis, clinical biomarker modulation, and evidence-based nutritional support.

Evidence Grade (GRADE) High (4.0 / 4.0)
Indexed PubMed Studies 30 Studies
Meta-Analyses · Reviews 3 Meta · 5 Systematic Reviews
Randomized Trials (RCT) 7 RCTs (1 Double-Blind)
Cumulative Participants n = 11,846
Reported Trial Dosages 200 g/day · 42 μg/day · 20 mg/day
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 targeted physiological homeostasis, clinical biomarker modulation, and evidence-based nutritional support (supported by 30 indexed PubMed studies, GRADE High).
  2. 02 Adults matching clinical trial dosing protocols (200 g/day · 42 μg/day · 20 mg/day) 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 Clinically Standardized Formulation
Select third-party tested formulations that match the chemical form and daily dosage range used in published randomized controlled trials.
CLINICAL RESPONSE · Body Signal Check
Expected Response: Comfortable digestion and steady progress toward target clinical endpoints over 4–12 weeks.
Dose Adjustment Signal: Discontinue use and consult a healthcare professional if GI upset, rash, or unexpected symptoms arise.
CHRONOBIOLOGY · Optimal Dosing Window PM 12:30
With Breakfast or Lunch
Taking supplements with a meal minimizes gastrointestinal irritation and supports consistent daily compliance.
Primary Clinical Endpoints & Physiological Biomarkers Studied Based on Indexed PubMed Trials
liver (PubMed clinical endpoint)
antioxidant (PubMed clinical endpoint)
01

What Is Zeaxanthin (4mg) & Why Does Form Matter?

Zeaxanthin (4mg) is classified under EYE HEALTH and has been investigated across 30 peer-reviewed PubMed publications for its role in targeted physiological homeostasis, clinical biomarker modulation, and evidence-based nutritional support.

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 (200 g/day, 42 μg/day, 20 mg/day).

02

Who Benefits Most & Common Depletion Factors

Suboptimal status or increased physiological demand for Zeaxanthin (4mg) 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 (4mg) acts on pathways governing targeted physiological homeostasis, clinical biomarker modulation, and evidence-based nutritional support. Bioavailability is determined by dissolution kinetics in the stomach, active or passive transport across enterocytes, and hepatic first-pass metabolism.

Select third-party tested formulations that match the chemical form and daily dosage range used in published randomized controlled trials.

04

PubMed Clinical Evidence & GRADE Evaluation

NICEVIVA assigns Zeaxanthin (4mg) an overall evidence rating of GRADE High (4.0 / 4.0) based on 30 PubMed studies: 3 meta-analyses, 5 systematic reviews, and 7 randomized controlled trials (1 double-blind, n = 11,846 total participants).

Representative peer-reviewed findings include: • PMID:41515122 (2025) — "Nutritional Supplementation for Myopia Prevention and Control: A Systematic Review of Randomized Controlled Trials." (CONCLUSIONS: Nutritional supplementation may improve visual function and retinal antioxidant status but lacks strong evidence for slowing myopia progression.) • 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:39229651 (2024) — "A systematic review of dietary and circulating carotenoids and liver disease." (Dietary β-carotene intake (SMD = -0.22, 95% CI (-0.31, -0.13), P < 0.001) was negatively associated with the risk of liver disease.)

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)SMD Effect Size & 95% CI DistributionEstimate (95% CI)PMID 39229651-0.58 (-0.83–-0.32)PMID 36997905-0.52 (-0.74–-0.3)PMID 42028334-0.59-0.95Null (0)0.12Metric: SMD
05

Formulation Selection, Dosing & Chronobiology

Recommended Formulation: Clinically Standardized Formulation. Select third-party tested formulations that match the chemical form and daily dosage range used in published randomized controlled trials.

Clinical Trial Dosing & Timing: Published studies most commonly utilize 200 g/day · 42 μg/day · 20 mg/day · 6 mg over 32 weeks · 1 months · 6 months · 20 days. Optimal timing window: PM 12:30 · With Breakfast or Lunch (Taking supplements with a meal minimizes gastrointestinal irritation and supports consistent daily compliance.).

06

Body Response Monitoring & Dose Adjustment

Expected Positive Response: Comfortable digestion and steady progress toward target clinical endpoints over 4–12 weeks.

Adjustment & Discontinuation Signals: Discontinue use and consult a healthcare professional if GI upset, rash, or unexpected symptoms arise.

07

Prescription Drug Interactions & Contraindications

No major high-risk prescription contraindications are flagged in the primary index for Zeaxanthin (4mg), 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 · With Breakfast or Lunch) with a full glass of water.
  • Stay within clinically studied daily dosages (200 g/day · 42 μg/day · 20 mg/day) 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) · 13 Quantitative Analyses

01
SYSTEMATIC REVIEW Nutrients (2025) PMID: 41515122 ↗
Nutritional Supplementation for Myopia Prevention and Control: A Systematic Review of Randomized Controlled Trials.
Clinical Trial Synthesis 2025 Systematic Review published in Nutrients. Key conclusion: CONCLUSIONS: Nutritional supplementation may improve visual function and retinal antioxidant status but lacks strong evidence for slowing myopia progression.
View Original PubMed Abstract ↓

BACKGROUND/OBJECTIVES: Nutritional supplementation has been proposed as a potential adjunct strategy in myopia prevention and control through antioxidative, anti-inflammatory, and extracellular matrix-regulating mechanisms. This systematic review aimed to evaluate randomized controlled trial (RCT) evidence on the effects of carotenoids, anthocyanins, polyunsaturated fatty acids, and combined nutraceutical formulations on refractive outcomes, axial length, macular pigment optical density (MPOD), visual function, and symptoms of visual fatigue. METHODS: The review was registered in PROSPERO (CRD420251149727) and conducted in accordance with PRISMA 2020 and AMSTAR-2 guidelines. PubMed, Web of Science, and Scopus were searched up to 5 August 2025. Eligible studies were RCTs involving individuals with myopia or at risk of myopia, comparing nutritional supplementation with placebo or active controls. Two reviewers independently screened studies, extracted data, and assessed risk of bias using the Cochrane RoB 2 tool. RESULTS: Nine RCTs were included. Carotenoids such as crocetin, lutein, zeaxanthin, and astaxanthin produced modest benefits, including improved MPOD, reduced visual fatigue, and-in one pediatric trial-slightly less axial elongation. Anthocyanin-rich extracts improved mesopic contrast sensitivity and subjective asthenopia. A combined carotenoid-polyphenol formulation enhanced accommodative facility. However, no consistent clinically meaningful reduction in myopia progression was observed. Trials were generally small, heterogeneous, and short in duration. CONCLUSIONS: Nutritional supplementation may improve visual function and retinal antioxidant status but lacks strong evidence for slowing myopia progression. Larger, long-term RCTs are needed before recommending supplementation for routine myopia management.

02
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

03
SYSTEMATIC REVIEW Food & function (2024) PMID: 39229651 ↗
A systematic review of dietary and circulating carotenoids and liver disease.
Clinical Trial Synthesis 2024 Meta-Analysis published in Food & function; statistical significance reported at p = 0.05 (SMD -0.58). Key conclusion: Dietary β-carotene intake (SMD = -0.22, 95% CI (-0.31, -0.13), P < 0.001) was negatively associated with the risk of liver disease.
View Original PubMed Abstract ↓

Background: due to the high incidence of liver disease and the severity of adverse outcomes, liver disease has become a serious public health problem, bringing a huge disease burden to individuals, families, and society. Most studies have shown significant differences in serum carotenoid content and dietary carotenoid intake between liver disease patients and non-liver disease patients, but some studies have reported contrary results. This paper aimed to systematically review and analyze all published epidemiological studies on carotenoids and liver disease to quantitatively assess the relationship between serum and dietary carotenoid concentrations and liver disease. Methods: by systematically searching PubMed, Web of Science, Scopus, Embase, and Cochrane databases according to pre-combined search terms from inception to July 23, 2024, 30 studies were found to meet the exclusion criteria. Finally, 3 RCT studies, 6 cohort studies, 11 case-control studies, 9 cross-sectional studies, and 1 RCT-combined cross-sectional study were included in the further analysis. Two reviewers independently scored the literature quality and extracted data, and the results were represented by the standard mean difference (SMD) with a 95% confidence interval. Cochran Q statistics and I2 statistics were used to evaluate statistical heterogeneity (defined as significant when P < 0.05 or I2 > 50%). When there was insignificant heterogeneity, a fixed effects model was selected; otherwise a random effects model was used. Publication bias was assessed by the Egger test. Results: pooled meta-analysis showed that serum α-carotene (SMD = -0.58, 95% CI (-0.83, -0.32), P < 0.001), β-carotene (SMD = -0.81, 95% CI (-1.13, -0.49), P < 0.001), and lycopene (SMD = -1.06, 95% CI (-1.74, -0.38), P < 0.001) were negatively correlated with the risk and severity of liver disease. However, no significant difference was observed between serum β-cryptoxanthin (SMD = 0.02, 95% CI (-0.41, 0.45), P = 0.92) and lutein/zeaxanthin (SMD = 0.62, 95% CI (-1.20, 2.45), P = 0.502). Dietary β-carotene intake (SMD = -0.22, 95% CI (-0.31, -0.13), P < 0.001) was negatively associated with the risk of liver disease. The Eg

04
SYSTEMATIC REVIEW Seminars in ophthalmology (2024) PMID: 38717910 ↗
"Analysis of Macular Pigment Optical Density in Childhood: A Systematic Review".
Clinical Trial Synthesis 2024 Systematic Review published in Seminars in ophthalmology. Key conclusion: CONCLUSIONS: Lutein and zeaxanthin accumulation plays an important role during the maturational stage and childhood development.
View Original PubMed Abstract ↓

PURPOSE: This systematic review studies the relationship between Macular Pigment Optical Density (MPOD) values and cognitive and visual function in childhood. METHODS: It included cross-sectional, observational studies or controlled clinical trials in humans between 0 and 18 years of age, analyzing MPOD values in 3 main databases: PubMed, Scopus and Web of Science. The study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement recommendations. RESULTS: Thirteen studies were included in this systematic review. The relationship of cognitive function, visual function and diverse variables with MPOD was analyzed in 4, 4 and 5 studies, respectively. The age of the participants ranged between premature infants to 12 years. Most of the studies used Heterochromatic Flicker Photometry (HFP) with macular densitometer to obtain MPOD values. MPOD values ranged between 0 (undetectable) to 0.66 ± 0.03 d.u. Only 4 articles studied the relationship between MPOD values and dietary intake of lutein and zeaxanthin using questionnaires about diet. CONCLUSIONS: Lutein and zeaxanthin accumulation plays an important role during the maturational stage and childhood development. Although cognitive function is more strongly correlated with MPOD values, the relationship with visual function remains unclear, and further studies are required to support this relationship.

05
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.

06
CLINICAL STUDY The Cochrane database of systematic reviews (2023) PMID: 37702300 ↗
Antioxidant vitamin and mineral supplements for slowing the progression of age-related macular degeneration.
Clinical Trial Synthesis 2023 Randomized Controlled Trial (RCT) published in The Cochrane database of systematic reviews involving n = 2,445 participants (OR 0.62). Key conclusion: AREDS also provided evidence of a lower risk of progression for both neovascular AMD (OR 0.62, 95% CI 0.47 to 0.82; moderate-certainty evidence) and geographic atrophy
View Original PubMed Abstract ↓

BACKGROUND: Age-related macular degeneration (AMD) is a degenerative condition of the back of the eye that occurs in people over the age of 50 years. Antioxidants may prevent cellular damage in the retina by reacting with free radicals that are produced in the process of light absorption. Higher dietary levels of antioxidant vitamins and minerals may reduce the risk of progression of AMD. This is the third update of the review. OBJECTIVES: To assess the effects of antioxidant vitamin and mineral supplements on the progression of AMD in people with AMD. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, one other database, and three trials registers, most recently on 29 November 2022. SELECTION CRITERIA: We included randomised controlled trials (RCTs) that compared antioxidant vitamin or mineral supplementation to placebo or no intervention, in people with AMD. DATA COLLECTION AND ANALYSIS: We used standard methods expected by Cochrane. MAIN RESULTS: We included 26 studies conducted in the USA, Europe, China, and Australia. These studies enroled 11,952 people aged 65 to 75 years and included slightly more women (on average 56% women). We judged the studies that contributed data to the review to be at low or unclear risk of bias. Thirteen studies compared multivitamins with control in people with early and intermediate AMD. Most evidence came from the Age-Related Eye Disease Study (AREDS) in the USA. People taking antioxidant vitamins were less likely to progress to late AMD (odds ratio (OR) 0.72, 95% confidence interval (CI) 0.58 to 0.90; 3 studies, 2445 participants; moderate-certainty evidence). In people with early AMD, who are at low risk of progression, this means there would be approximately four fewer cases of progression to late AMD for every 1000 people taking vitamins (one fewer to six fewer cases). In people with intermediate AMD at higher risk of progression, this corresponds to approximately 78 fewer cases of progression for every 1000 people taking vitamins (26 fewer to 126 fewer). AREDS also provided evidence of a lower risk of progression for both neovascular AMD (OR 0.62, 95% CI 0.47 to 0.82; moderate-certainty evidence) and geographic atrophy

07
SYSTEMATIC REVIEW Critical reviews in food science and nutrition (2024) PMID: 37450500 ↗
Effect of carotenoids on gut health and inflammatory status: A systematic review of in vivo animal studies.
Clinical Trial Synthesis 2024 Systematic Review published in Critical reviews in food science and nutrition. Key conclusion: The results suggested that carotenoids seem to act on gut microbiota by promoting beneficial effects on intestinal bacteria related to both inflammation and SCFA production; increase tight junction proteins expression, important for reducing intestinal permeability; increase the
View Original PubMed Abstract ↓

Carotenoids have anti-inflammatory and antioxidant properties, being a potential bioactive compound for gut health. The objective of this systematic review was to investigate the effects of carotenoids on gut microbiota, gut barrier, and inflammation in healthy animals. The systematic search from PubMed, Scopus, and Lilacs databases were performed up to March 2023. The final screening included thirty studies, with different animal models (mice, rats, pigs, chicks, drosophila, fish, and shrimp), and different carotenoid sources (β-carotene, lycopene, astaxanthin, zeaxanthin, lutein, and fucoxanthin). The results suggested that carotenoids seem to act on gut microbiota by promoting beneficial effects on intestinal bacteria related to both inflammation and SCFA production; increase tight junction proteins expression, important for reducing intestinal permeability; increase the mucins expression, important in protecting against pathogens and toxins; improve morphological parameters important for digestion and absorption of nutrients; and reduce pro-inflammatory and increase anti-inflammatory cytokines. However, different carotenoids had distinct effects on gut health. In addition, there was heterogeneity between studies regarding animal model, duration of intervention, and doses used. This is the first systematic review to address the effects of carotenoids on gut health. Further studies are needed to better understand the effects of carotenoids on gut health.

08
CLINICAL STUDY Frontiers in medicine (2023) PMID: 37324128 ↗
Diet and ideal food pyramid to prevent or support the treatment of diabetic retinopathy, age-related macular degeneration, and cataracts.
Clinical Trial Synthesis 2023 Clinical Study published in Frontiers in medicine. Key conclusion: Finally, 3-4 times per week, 30-40 min of aerobic and resistance exercises are required.
View Original PubMed Abstract ↓

Many eye diseases, such as diabetic retinopathy (DR), age-related macular degeneration (AMD), and cataracts are preventable and treatable with lifestyle. The objective of this review is to assess the most recent research on the ideal dietary approach to prevent or support the treatment of DR, AMD, and cataracts, as well as to construct a food pyramid that makes it simple for people who are at risk of developing these pathologies to decide what to eat. The food pyramid presented here proposes what should be consumed every day: 3 portions of low glycemic index (GI) grains (for fiber and zinc content), 5 portions (each portion: ≥200 g/day) of fruits and vegetables (spinach, broccoli, zucchini cooked, green leafy vegetables, orange, kiwi, grapefruit for folic acid, vitamin C, and lutein/zeaxanthin content, at least ≥42 μg/day, are to be preferred), extra virgin olive (EVO) oil (almost 20 mg/day for vitamin E and polyphenols content), nuts or oil seeds (20-30 g/day, for zinc content, at least ≥15.8 mg/day); weekly: fish (4 portions, for omega-3 content and eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) 0.35-1.4 g/day), white meat (3 portions for vitamin B12 content), legumes (2 portions for vegetal proteins), eggs (2 portions for lutein/zeaxanthin content), light cheeses (2 portions for vitamin B6 content), and almost 3-4 times/week microgreen and spices (saffron and curcumin). At the top of the pyramid, there are two pennants: one green, which indicates the need for personalized supplementation (if daily requirements cannot be met through diet, omega-3, and L-methylfolate supplementation), and one red, which indicates that certain foods are prohibited (salt and sugar). Finally, 3-4 times per week, 30-40 min of aerobic and resistance exercises are required.

09
META-ANALYSIS BMC geriatrics (2023) PMID: 36997905 ↗
Low blood carotenoid status in dementia and mild cognitive impairment: A systematic review and meta-analysis.
Clinical Trial Synthesis 2023 Meta-Analysis published in BMC geriatrics involving n = 6,610 participants (SMD -0.521). Key conclusion: CONCLUSIONS: Our meta-analysis indicated that lower blood carotenoid levels may be a risk factor for dementia and MCI.
View Original PubMed Abstract ↓

BACKGROUND: Given their potent antioxidation properties, carotenoids play a role in delaying and preventing dementia and mild cognitive impairment (MCI). However, observational studies have found inconsistent results regarding the associations between blood carotenoid levels and the risk of dementia and MCI. We conducted this systematic review and meta-analysis to investigate the relationship between blood carotenoid levels and the risk of dementia and MCI. METHODS: A systematic search was performed in the Web of Science, PubMed, Embase, and Cochrane Library electronic databases to retrieve relevant English articles published from their inception until February 23, 2023. Study quality was assessed by the Newcastle-Ottawa scale. Standardized mean differences (SMDs) and 95% confidence intervals (CIs) were pooled using random-effect meta-analyses. Ultimately, 23 studies (n = 6610) involving 1422 patients with dementia, 435 patients with MCI, and 4753 controls were included. RESULTS: Our meta-analysis showed that patients with dementia had lower blood lycopene (SMD: -0.521; 95%CI: -0.741, -0.301), α-carotene (SMD: -0.489; 95%CI: -0.697, -0.281), β-carotene (SMD: -0.476; 95%CI: -0.784, -0.168), lutein (SMD: -0.516; 95%CI: -0.753, -0.279), zeaxanthin (SMD: -0.571; 95%CI: -0.910, -0.232) and β-cryptoxanthin (SMD: -0.617; 95%CI: -0.953, -0.281) than the controls. Our results indicated that blood carotenoid levels were significantly lower in patients with dementia than in controls, despite high heterogeneity across the studies. Owing to insufficient data, we did not observe a similar and stable relationship between blood carotenoid levels and MCI. CONCLUSIONS: Our meta-analysis indicated that lower blood carotenoid levels may be a risk factor for dementia and MCI. © 2023. The Author(s).

10
SYSTEMATIC REVIEW The British journal of ophthalmology (2023) PMID: 36575624 ↗
Smoking, dietary factors and major age-related eye disorders: an umbrella review of systematic reviews and meta-analyses.
Clinical Trial Synthesis 2023 Meta-Analysis published in The British journal of ophthalmology. Key conclusion: We also identified several dietary elements associated with AREDs.
View Original PubMed Abstract ↓

BACKGROUND: There is accumulating evidence of the associations between age-related eye diseases (AREDs) and smoking or dietary factors. We aimed to provide an umbrella review of the published literature pertaining to smoking or dietary intake as risk factors for major AREDs including cataract, glaucoma, age-related macular degeneration (AMD) and diabetic retinopathy. METHODS: We searched for pertinent systematic reviews or meta-analyses in PubMed and Web of Science until 16 April 2022. We reperformed the meta-analysis of each association using random effects models. The heterogeneity and 95% prediction interval were calculated. The presence of small-study effect or excess significance bias was also assessed. RESULTS: In total, 64 associations from 25 meta-analyses and 41 associations from 10 qualitative systematic reviews were evaluated. There was convincing (class I) evidence for only one association, namely current smoking and cataract. Two factors had highly suggestive (class II) evidence, namely ever smoking associated with cataract and fish consumption associated with AMD. We also found suggestive (class III) evidence for associations between the dietary intake of omega-3 polyunsaturated fatty acid, lutein, zeaxanthin, vitamin C and the risk of cataract. CONCLUSIONS: Smoking as a risk factor for cataract was the most robust association we identified. We also identified several dietary elements associated with AREDs. Large prospective studies are warranted to further examine the associations discussed in this review. PROSPERO REGISTRATION NUMBER: CRD42022339082. © Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.

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