Beta-Carotene
Research reviewed: Up until 03/2026
Beta-Carotene (Beta-carotene) is a dietary supplement with 26 published peer-reviewed studies involving 61,840 participants, researched for Cancer Prevention & Risk, Antioxidant & Immune Effects, Skin Health & Photoprotection and 3 more areas.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Cancer Prevention & Risk
ModerateAntioxidant & Immune Effects
ModerateSkin Health & Photoprotection
ModerateProvitamin A, Cognition & Longevity
StrongClinical trials
ModerateSystematic reviews
WeakResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Cancer Prevention & Risk
To assess beta-carotene + retinol supplementation on lung cancer incidence in high-risk individuals.
Study Type
RCT (CARET trial)
Purpose
To assess beta-carotene + retinol supplementation on lung cancer incidence in high-risk individuals.
Dose
30 mg beta-carotene + 25,000 IU retinol daily
Participants
18,314 heavy smokers and asbestos workers
Duration
4 years
Results
Supplementation increased lung cancer risk by 28% and overall mortality by 17% in this high-risk population; trial stopped early.
How They Measured It
Cancer incidence by national registry; mortality
To assess beta-carotene supplementation on cancer incidence in healthy male physicians.
Study Type
Large RCT (Physicians Health Study)
Purpose
To assess beta-carotene supplementation on cancer incidence in healthy male physicians.
Dose
50 mg beta-carotene every other day
Participants
22,071 male US physicians
Duration
12 years
Results
No significant effect on cancer or cardiovascular disease incidence in this healthy population; no harm observed.
How They Measured It
Cancer incidence by physician report and registry linkage
To evaluate the benefit-risk profile of beta-carotene supplementation for cancer prevention.
Study Type
Meta-analysis
Purpose
To evaluate the benefit-risk profile of beta-carotene supplementation for cancer prevention.
Dose
Various doses reviewed
Participants
Multiple large trials
Duration
Review
Results
Beta-carotene supplementation increases lung cancer risk in smokers; no benefit in non-smokers; food-derived beta-carotene remains safe and beneficial.
How They Measured It
Meta-analysis of all major RCTs
Antioxidant & Immune Effects
To evaluate beta-carotene supplementation on immune cell function in elderly subjects.
Study Type
RCT
Purpose
To evaluate beta-carotene supplementation on immune cell function in elderly subjects.
Dose
50 mg beta-carotene daily
Participants
63 men aged 65+
Duration
10-12 weeks
Results
Significant enhancement of NK cell activity and DTH response; beneficial immune stimulatory effect in older adults.
How They Measured It
Delayed-type hypersensitivity skin response, NK cell activity
To characterise the antioxidant mechanisms of beta-carotene including singlet oxygen quenching and radical chain-breaking.
Study Type
In vitro mechanistic study
Purpose
To characterise the antioxidant mechanisms of beta-carotene including singlet oxygen quenching and radical chain-breaking.
Dose
1-50 µM
Participants
Cell-free assay
Duration
Acute
Results
Beta-carotene effectively quenched singlet oxygen and inhibited lipid peroxidation in a dose-dependent manner under physiological oxygen tension.
How They Measured It
Singlet oxygen quenching constants; lipid peroxidation inhibition assay
Skin Health & Photoprotection
To assess beta-carotene supplementation for protection against UV-induced skin damage.
Study Type
Systematic review and meta-analysis
Purpose
To assess beta-carotene supplementation for protection against UV-induced skin damage.
Dose
12-180 mg/day across studies
Participants
Multiple trials reviewed
Duration
Review
Results
Beta-carotene supplementation for >=10 weeks increased MED by average 1.4 mJ/cm2; photoprotective effect modest but consistent.
How They Measured It
Minimal erythema dose (MED); skin redness measurement
To assess beta-carotene and sun exposure interactions on skin aging and photocarcinogenesis.
Study Type
RCT
Purpose
To assess beta-carotene and sun exposure interactions on skin aging and photocarcinogenesis.
Dose
20 mg beta-carotene daily
Participants
40 healthy adults with fair skin
Duration
12 weeks
Results
Beta-carotene supplementation reduced UV-induced DNA damage markers in skin biopsies; visible skin health scores improved vs placebo.
How They Measured It
Skin wrinkling score, DNA damage biomarkers in skin biopsies
Provitamin A, Cognition & Longevity
To evaluate beta-carotene bioavailability and conversion efficiency to vitamin A across populations.
Study Type
Meta-analysis
Purpose
To evaluate beta-carotene bioavailability and conversion efficiency to vitamin A across populations.
Dose
Various supplemental forms
Participants
Multiple trials
Duration
Review
Results
Beta-carotene conversion efficiency to retinol is highly variable (range 3.6:1 to 28:1 by weight); food matrix and individual factors are critical determinants.
How They Measured It
Serum retinol response; isotope dilution studies
To assess beta-carotene supplementation for correction of vitamin A deficiency in children.
Study Type
RCT in developing country setting
Purpose
To assess beta-carotene supplementation for correction of vitamin A deficiency in children.
Dose
60 mg beta-carotene every 4 months
Participants
2500 preschool children with vitamin A deficiency
Duration
24 months
Results
Beta-carotene supplementation significantly improved serum retinol and reduced xerophthalmia prevalence by 50%.
How They Measured It
Serum retinol, clinical xerophthalmia assessment
To explore associations between plasma beta-carotene and cognitive decline in older adults.
Study Type
Observational cohort
Purpose
To explore associations between plasma beta-carotene and cognitive decline in older adults.
Dose
Observational
Participants
1800 adults aged 65+ in EPESE cohort
Duration
8-year follow-up
Results
Low plasma beta-carotene associated with 1.5x greater risk of cognitive decline; higher intake protective for memory and executive function.
How They Measured It
MMSE, Trail Making Test; plasma carotenoid by HPLC
To evaluate beta-carotene's long-term effects on cognitive function.
Study Type
Long-term RCT (Physicians Health Study II substudy)
Purpose
To evaluate beta-carotene's long-term effects on cognitive function.
Dose
50 mg beta-carotene every other day
Participants
4052 male physicians in cognitive substudy
Duration
18 years
Results
Long-term beta-carotene supplementation (>=15 years) associated with significantly better verbal memory and cognitive scores vs placebo.
How They Measured It
Telephone cognitive assessments: general cognition, verbal memory
To assess the relationship between serum beta-carotene and all-cause mortality risk.
Study Type
Cross-sectional epidemiology
Purpose
To assess the relationship between serum beta-carotene and all-cause mortality risk.
Dose
Observational
Participants
13,000 adults in NHANES III follow-up
Duration
15 years
Results
Lowest serum beta-carotene quartile associated with 40% higher all-cause mortality; association persisted after adjusting for smoking status.
How They Measured It
Serum beta-carotene; death certificate linkage
Clinical trials
To investigate the effects of Beta-Carotene in oral antioxidant and lutein/zeaxanthin supplements slow geographic atrophy progression to the fovea in age-related macular degeneration.
Study Type
Randomized, double-blind, placebo-controlled
Purpose
To investigate the effects of Beta-Carotene in oral antioxidant and lutein/zeaxanthin supplements slow geographic atrophy progression to the fovea in age-related macular degeneration.
Dose
Beta-Carotene (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
To determine whether oral micronutrient supplementation slows geographic atrophy (GA) progression in age-related macular degeneration (AMD).
How They Measured It
See study for outcome measures
To investigate the effects of Beta-Carotene in comparing a diet-wide panel of biomarkers of food intake in whole blood and 24-hour urine and self-reported with known dietary intakes: randomized fee
Study Type
Randomized, double-blind, placebo-controlled
Purpose
To investigate the effects of Beta-Carotene in comparing a diet-wide panel of biomarkers of food intake in whole blood and 24-hour urine and self-reported with known dietary intakes: randomized fee
Dose
Beta-Carotene (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
Specific metabolites detected in biofluids after food intake have been proposed as objective markers to address limitations with traditional dietary assessment methods. Although hundreds of metabolites have been associated with foods or food groups, they require validation.
How They Measured It
See study for outcome measures
To investigate the effects of Beta-Carotene in voucher for healthy foods and diabetes control: a randomized clinical trial.
Study Type
Randomized, double-blind, placebo-controlled
Purpose
To investigate the effects of Beta-Carotene in voucher for healthy foods and diabetes control: a randomized clinical trial.
Dose
Beta-Carotene (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
Programs to improve access to healthy foods for people with diabetes exist in some jurisdictions but not others, and their effects on disease control are not established.
How They Measured It
See study for outcome measures
To investigate the effects of Beta-Carotene in efficacy of natural β-carotene chewable tablets derived from banana (musa aa) pulp in reducing uv-induced skin erythema.
Study Type
Randomized, double-blind, placebo-controlled
Purpose
To investigate the effects of Beta-Carotene in efficacy of natural β-carotene chewable tablets derived from banana (musa aa) pulp in reducing uv-induced skin erythema.
Dose
Beta-Carotene (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
UV radiation is a primary cause of skin damage and photoaging. β-carotene, a potent antioxidant, aids in mitigating UV-induced oxidative stress and enhancing skin photoprotection. This research aimed to evaluate the efficacy of a nutraceutical product designed to prevent photoaging.
How They Measured It
See study for outcome measures
To investigate the effects of Beta-Carotene in red palm olein biscuit supplementation modulates gut microbiota in vitamin a deficient rural malaysian schoolchildren: a randomised controlled trial.
Study Type
Randomized, double-blind, placebo-controlled
Purpose
To investigate the effects of Beta-Carotene in red palm olein biscuit supplementation modulates gut microbiota in vitamin a deficient rural malaysian schoolchildren: a randomised controlled trial.
Dose
Beta-Carotene (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
in modulating gut microbiota in vitamin A-deficient children by enhancing microbial network cohesiveness and enriching potentially beneficial bacterial taxa which are linked to enhanced micronutrient and haematological outcomes. These findings lay a valuable foundation and expand the existing evidence base for understanding the relationship between provitamin A carotenoids and gut microbiota.
How They Measured It
See study for outcome measures
To investigate the effects of Beta-Carotene in assessing the effect of a food voucher on the dietary intake of patients with diabetes using the canadian diet history questionnaire iii: a randomized
Study Type
Randomized, double-blind, placebo-controlled
Purpose
To investigate the effects of Beta-Carotene in assessing the effect of a food voucher on the dietary intake of patients with diabetes using the canadian diet history questionnaire iii: a randomized
Dose
Beta-Carotene (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
The high cost of healthy foods makes it difficult for people with a low income to manage diabetes. This study examined the effects of a monthly grocery voucher on the dietary intake, assessed through the Canadian Diet History Questionnaire III, of diabetes patients facing food or financial insecurity. We also assessed the impact on levels of hemoglobin A1c, beta-carotene, and ascorbic acid.
How They Measured It
See study for outcome measures
Systematic reviews
To investigate the effects of Beta-Carotene in effectiveness in preventing hearing loss: meta-analysis of dietary consumption studies.
Study Type
Systematic review and meta-analysis
Purpose
To investigate the effects of Beta-Carotene in effectiveness in preventing hearing loss: meta-analysis of dietary consumption studies.
Dose
Beta-Carotene (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
The systematic review with meta-analysis aimed to verify the occurrence of a protective effect on hearing loss due to a higher intake of carotenoids, vitamins A, C, E, and folate present in diets.
How They Measured It
See study for outcome measures
To investigate the effects of Beta-Carotene in a systematic review of dietary and circulating carotenoids and liver disease.
Study Type
Systematic review
Purpose
To investigate the effects of Beta-Carotene in a systematic review of dietary and circulating carotenoids and liver disease.
Dose
6 mg
Participants
Participants not specified
Duration
Duration not specified
Results
: lower serum concentrations of α-carotene, β-carotene, and lycopene were associated with a higher risk of liver disease. Meanwhile, dietary intake of β-carotene could reduce the incidence of liver disease. However, for malignant diseases such as liver cancer, it did not show the significant effects of carotenoid supplementation.
How They Measured It
See study for outcome measures
To investigate the effects of Beta-Carotene in randomized controlled trials for oral leukoplakia.
Study Type
Review
Purpose
To investigate the effects of Beta-Carotene in randomized controlled trials for oral leukoplakia.
Dose
Beta-Carotene (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
n, and photodynamic therapy in the treatment of oral leukoplakia. Some interventions showed reductions in lesion size or short-term recurrence, but none proved effective in preventing long-term recurrence or malignant transformation. Data remain limited, and further rigorously designed, large randomized controlled trials are needed to guide potential new management approaches for oral leukoplakia.
How They Measured It
See study for outcome measures
To investigate the effects of Beta-Carotene in antioxidant lipid supplement on cardiovascular risk factors: a systematic review and meta-analysis.
Study Type
Systematic review and meta-analysis
Purpose
To investigate the effects of Beta-Carotene in antioxidant lipid supplement on cardiovascular risk factors: a systematic review and meta-analysis.
Dose
Beta-Carotene (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
s. Notably, n9 fatty acid increased triglyceride and hemoglobin A1C in the total population, which increases CVD risk. Antioxidant lipid supplementations ameliorate cardiometabolic risk factors, while their effect may depend on type and cardiometabolic health status. Long-term RCTs are needed to corroborate risk-benefit ratios across different antioxidant functional lipid supplementation settings.
How They Measured It
See study for outcome measures
To investigate the effects of Beta-Carotene in association of antioxidants intake in diet and supplements with risk of alzheimer's disease: a systematic review and dose-response meta-analysis of pr
Study Type
Systematic review and meta-analysis
Purpose
To investigate the effects of Beta-Carotene in association of antioxidants intake in diet and supplements with risk of alzheimer's disease: a systematic review and dose-response meta-analysis of pr
Dose
Beta-Carotene (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
Previous studies have shown that antioxidants may be associated with risk of Alzheimer's disease (AD). However, some findings have failed to demonstrate a significant correlation. To rigorously evaluate this relationship, a comprehensive review and meta-analysis were conducted.
How They Measured It
See study for outcome measures
To investigate the effects of Beta-Carotene in risk factors for gastric cancer: an umbrella review of systematic reviews and meta-analyses.
Study Type
Systematic review
Purpose
To investigate the effects of Beta-Carotene in risk factors for gastric cancer: an umbrella review of systematic reviews and meta-analyses.
Dose
Beta-Carotene (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
This umbrella review aims to critically appraise and synthesize epidemiological evidence from meta-analyses to identify and classify risk and protective factors associated with gastric cancer.
How They Measured It
See study for outcome measures
To investigate the effects of Beta-Carotene in the influence of nutrition on hpv-associated inflammation: a systematic review and meta-analysis.
Study Type
Systematic review and meta-analysis
Purpose
To investigate the effects of Beta-Carotene in the influence of nutrition on hpv-associated inflammation: a systematic review and meta-analysis.
Dose
Beta-Carotene (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
Chronic infection with human papillomavirus (HPV) is a key etiologic cause of cervical intraepithelial neoplasia (CIN) and cervical cancer.
How They Measured It
See study for outcome measures
To investigate the effects of Beta-Carotene in protective effects of dietary nutrients on hearing loss: a systematic review and meta-analysis.
Study Type
Systematic review and meta-analysis
Purpose
To investigate the effects of Beta-Carotene in protective effects of dietary nutrients on hearing loss: a systematic review and meta-analysis.
Dose
1.5 billion
Participants
Participants not specified
Duration
Duration not specified
Results
rd most prevalent disability globally, significantly impacting individuals and society, and imposing a substantial healthcare burden. The World Health Organization reports that over 1.5 billion people worldwide experience hearing loss, with one-third of these cases attributed to preventable factors. Recently, the influence of diet and nutrition on auditory health has garnered increasing attention.
How They Measured It
See study for outcome measures
Frequently Asked Questions
Common questions about Beta-Carotene research
There are currently 26 peer-reviewed studies on Beta-Carotene (Beta-carotene), involving 61,840 total participants. Research covers Cancer Prevention & Risk, Antioxidant & Immune Effects, Skin Health & Photoprotection and 3 more areas. The overall evidence strength is rated as Strong.
The evidence is currently rated as "Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (14 human studies), and reported outcomes.
Beta-Carotene has been researched for: Cancer Prevention & Risk, Antioxidant & Immune Effects, Skin Health & Photoprotection, Provitamin A, Cognition & Longevity, Clinical trials, Systematic reviews. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 14 out of 26 studies are human trials. Human trials carry more weight in our evidence scoring system.
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