Research
Beta-Carotene
89 peer-reviewed studies curated from PubMed and Semantic Scholar.
Studies
Sorted by quality and recency
Dietary β-Carotene, Vitamin A, and Retinol Intake and Prevalence of Colorectal Adenoma: A Cross-Sectional Study and Meta-Analysis.
Cross-sectional study and meta-analysis investigating the relationship between dietary intake of beta-carotene, vitamin A, and retinol and the prevalence of colorectal adenoma. Higher intake of beta-carotene and vitamin A was associated with a lower prevalence of colorectal adenoma, while higher retinol intake was linked to increased prevalence, especially in high-fat diets.
The role of beta-carotene in cattle infertility, mastitis and milk yield: A systematic review and meta-analysis.
Systematic review and meta-analysis of 29 studies on beta-carotene's effects on cattle fertility, mastitis, and milk yield. Significant positive effects were found for milk yield, pregnancy at first service, and reduced clinical mastitis, though results varied across parameters.
Association between β-carotene supplementation and risk of cancer: a meta-analysis of randomized controlled trials.
Meta-analysis of 18 studies from 8 randomized controlled trials assessing the association between supplemental beta-carotene intake and cancer risk. No significant association was found with overall cancer incidence, but beta-carotene intake increased lung cancer risk, particularly in smokers.
Association Between Beta-Carotene Supplementation and Mortality: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Systematic review and meta-analysis of 31 RCTs with 216,734 subjects examining beta-carotene supplementation's effect on mortality. Beta-carotene showed no preventive effect on overall mortality but increased lung cancer mortality risk and decreased HIV-related mortality risk.
The effects of β-carotene on osteoporosis: a systematic review and meta-analysis of observational studies.
Systematic review and meta-analysis of observational studies evaluating the effect of beta-carotene on osteoporosis. The intake of beta-carotene was unassociated with the overall risk of osteoporosis but showed a negative association in male, female, and Asian subgroups. Beta-carotene intake was positively associated with bone mineral density in Asian participants.
The effect of β-carotene on the mortality of male smokers is modified by smoking and by vitamins C and E: evidence against a uniform effect of nutrient.
The study analyzed the effect of β-carotene supplementation on mortality in male smokers from the ATBC Study. β-carotene increased mortality in those who started smoking at ≥21 years and smoked ≥21 cigarettes/day. The effect was further modified by dietary vitamin C, fruit and vegetable intake, and vitamin E supplementation, indicating heterogeneity in the β-carotene effect on mortality.
β-Carotene Supplementation and Lung Cancer Incidence in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study: The Role of Tar and Nicotine.
The ATBC Study was a randomized, double-blind intervention trial with 29,133 male smokers, examining the effect of β-carotene supplementation on lung cancer incidence. The study found that β-carotene supplementation increased the risk of lung cancer in smokers, regardless of the tar or nicotine content of cigarettes smoked.
Vitamin A and Breast Cancer Survival: A Systematic Review and Meta-analysis.
Systematic review and meta-analysis of 10 studies with 19,450 breast cancer cases examining the association between vitamin A intake and breast cancer survival. Dietary intake of beta-carotene was significantly associated with improved overall survival, while other vitamin A derivatives showed no significant effect.
Effects of α-tocopherol and β-carotene supplementation on liver cancer incidence and chronic liver disease mortality in the ATBC study.
RCT of 29,105 Finnish male smokers evaluating the effects of supplemental alpha-tocopherol and beta-carotene on liver cancer incidence and chronic liver disease mortality over 24 years. The study found no effect of supplementation on reducing the risk of liver cancer or CLD mortality.
The contribution of β-carotene to vitamin A supply of humans.
Meta-analysis of 11 studies from 8 countries with 121,256 participants estimating the contribution of β-carotene to vitamin A supply in industrialized countries. The study found that preformed vitamin A accounts for 65% of total intake, while carotenoids, including β-carotene, make up 35%. A safe vitamin A intake cannot be reached by consuming only one component alone.
Effects of beta-carotene supplements on cancer prevention: meta-analysis of randomized controlled trials.
Meta-analysis of 6 RCTs with 40,544 participants assessed the effects of beta-carotene supplements on cancer prevention. Beta-carotene showed no preventive effect on cancer incidence or mortality but increased the risk of urothelial cancer, especially bladder cancer, and marginally increased cancer risk among current smokers.
Effect of alpha-tocopherol and beta-carotene supplementation on macrovascular complications and total mortality from diabetes: results of the ATBC Study.
The ATBC Study, a double-blind, randomized trial with 29,133 middle-aged male smokers, investigated the effects of alpha-tocopherol and beta-carotene supplementation on diabetic macrovascular complications and total mortality. Neither supplementation affected the risk of macrovascular complications or total mortality during the intervention period or the extended 19-year follow-up.
A systematic review of treatment options for dermal photosensitivity in erythropoietic protoporphyria.
Systematic review of 25 studies on treatment options for erythropoietic protoporphyria, focusing on beta-carotene, NAC, cysteine, dihydroxyacetone/Lawson, vitamin C, and canthaxanthin. Most studies were from the 1970s and lacked standardized efficacy criteria. The review found insufficient evidence to prove efficacy of any treatments studied.
Beta-carotene in multivitamins and the possible risk of lung cancer among smokers versus former smokers: a meta-analysis and evaluation of national brands.
Meta-analysis of large randomized trials assessing the risk of lung cancer associated with beta-carotene supplementation among smokers and former smokers. Beta-carotene supplementation was significantly associated with an increased risk of lung cancer among current smokers, but not among former smokers. Beta-carotene was prevalent in multivitamins, especially those marketed for visual health.
Effect of alpha-tocopherol and beta-carotene supplementation on the incidence of type 2 diabetes.
The ATBC Study, a double-blind, controlled trial with 29,133 male smokers, investigated the effect of alpha-tocopherol and beta-carotene supplementation on type 2 diabetes incidence. Neither supplementation significantly affected diabetes incidence, and baseline serum levels were not associated with diabetes risk.
Effects of alpha-tocopherol and beta-carotene supplementation on upper aerodigestive tract cancers in a large, randomized controlled trial.
RCT of 29,133 male smokers in Finland examining the effects of daily supplementation with alpha-tocopherol and beta-carotene on upper aerodigestive tract cancers. No overall effect on cancer incidence or mortality was found, though beta-carotene may reduce the incidence of early-stage laryngeal tumors.
Beta carotene supplementation and age-related maculopathy in a randomized trial of US physicians.
Randomized, double-masked, placebo-controlled trial among 22,071 US male physicians aged 40 to 84 years, testing beta carotene supplementation (50 mg every other day) on age-related maculopathy (ARM). After 12 years, beta carotene showed no significant effect on ARM incidence compared to placebo.
A randomized trial of beta carotene supplementation and cognitive function in men: the Physicians' Health Study II.
The study added cognitive testing to the Physicians' Health Study II, a randomized trial of beta carotene supplementation. Among 4052 continuing participants with a mean treatment duration of 18 years, the beta carotene group showed significantly higher cognitive scores compared to placebo. No significant cognitive differences were found in 1904 newly recruited subjects with a mean treatment duration of 1 year.
Changes in cholesterol and triglyceride concentrations in the Vanguard population of the Carotene and Retinol Efficacy Trial (CARET).
The Beta-Carotene and Retinol Efficacy Trial (CARET) analyzed serum lipids in 1474 participants. The study found that serum cholesterol and triglycerides were significantly higher in participants receiving vitamin A and/or beta-carotene compared to the placebo group. These differences may partly explain the increased cardiovascular mortality observed in the active intervention arm.
Age-related cataract in a randomized trial of beta-carotene in women.
RCT from the Women's Health Study examining beta-carotene supplementation (50 mg on alternate days) in 39,876 female health professionals aged 45 or older. The study found no large beneficial or harmful effect of beta-carotene on the development of cataract over a median treatment duration of 2.1 years.
Effect of alpha-tocopherol and beta-carotene supplementation on coronary heart disease during the 6-year post-trial follow-up in the ATBC study.
The study evaluated the 6-year post-trial effects of alpha-tocopherol and beta-carotene supplementation on coronary heart disease in male smokers. Beta-carotene supplementation was associated with an increased post-trial risk of first-ever non-fatal myocardial infarction, while alpha-tocopherol showed no significant effect. The findings do not support the use of these supplements for CHD prevention in this population.
The Beta-Carotene and Retinol Efficacy Trial: incidence of lung cancer and cardiovascular disease mortality during 6-year follow-up after stopping beta-carotene and retinol supplements.
The Beta-Carotene and Retinol Efficacy Trial (CARET) tested the effect of beta-carotene and retinyl palmitate on lung cancer and mortality in 18,314 high-risk participants. The trial was stopped early due to increased lung cancer incidence and mortality in the intervention group. Post-intervention follow-up showed persistent but not statistically significant adverse effects, with higher risks in females.
A randomized trial of beta carotene and age-related cataract in US physicians.
A randomized, double-masked, placebo-controlled trial of 22,071 male US physicians aged 40 to 84 years examined the effect of beta carotene supplementation on age-related cataract development. Overall, there was no significant difference in cataract incidence or extraction between the beta carotene and placebo groups. However, among current smokers, beta carotene appeared to reduce the risk of cataract by about one fourth.
Circulating levels of retinol, tocopherol and carotenoid in Nepali pregnant and postpartum women following long-term beta-carotene and vitamin A supplementation.
Randomized community supplementation trial in Nepali pregnant and postpartum women to assess the effects of beta-carotene and vitamin A supplementation on serum levels of retinol, tocopherol, and carotenoids. Beta-carotene supplementation increased serum levels of tocopherol and other carotenoids compared to placebo.
Effects of supplemental alpha-tocopherol and beta-carotene on urinary tract cancer: incidence and mortality in a controlled trial (Finland).
RCT involving 29,133 male smokers in Finland to assess the effects of alpha-tocopherol and beta-carotene supplementation on urinary tract cancer incidence and mortality. The study found no preventive effect of these supplements on urothelial or renal cell cancers.
Controlled trial of alpha-tocopherol and beta-carotene supplements on stroke incidence and mortality in male smokers.
RCT examining the effects of alpha-tocopherol and beta-carotene supplementation on stroke incidence and mortality in 28,519 male smokers. Alpha-tocopherol increased the risk of fatal hemorrhagic strokes but decreased the risk of cerebral infarction. Beta-carotene increased the risk of intracerebral hemorrhage. Overall effects on total stroke incidence and mortality were nonsignificant.
Effect of dispersed form on the bioavailability of β-carotene from daily intake in humans.
A randomized double-blind crossover study compared the bioavailability of β-carotene from an emulsion dispersion formulation (EM) and a crystal dispersion formulation (CR) in humans over 2 weeks. EM-β-carotene enhanced plasma β-carotene concentrations approximately 4-fold, while CR-β-carotene showed no significant enhancement. Bioaccessibility was higher for EM-β-carotene, suggesting its potential as a food coloring agent with added value.
Dietary, circulating beta-carotene and risk of all-cause mortality: a meta-analysis from prospective studies.
Meta-analysis of observational studies evaluating dietary and circulating beta-carotene levels in relation to all-cause mortality. Higher beta-carotene intake and serum levels were associated with a significantly lower risk of all-cause mortality.
Biofortified yellow cassava and vitamin A status of Kenyan children: a randomized controlled trial.
RCT assessing the effect of consuming biofortified yellow cassava on serum retinol concentration in Kenyan schoolchildren with marginal vitamin A status. Yellow cassava and beta-carotene supplementation increased serum retinol and beta-carotene concentrations, suggesting an efficacious approach to improve vitamin A status.
Sunscreen and prevention of skin aging: a randomized trial.
RCT in Nambour, Australia, with 903 adults under 55, comparing daily vs discretionary sunscreen use and β-carotene supplementation vs placebo. Daily sunscreen use retarded skin aging by 24% compared to discretionary use. β-carotene supplementation showed no overall effect on skin aging.
Low-dose beta-carotene supplementation and deworming improve serum vitamin A and beta-carotene concentrations in preschool children of Bangladesh.
RCT involving 244 preschool children in Bangladesh infected with Ascaris lumbricoides, randomized into four groups to receive beta-carotene supplementation and/or antihelminthic therapy. Serum retinol and beta-carotene levels increased significantly in the group receiving both interventions, indicating a synergistic effect on vitamin A status.
Beta-carotene supplementation and cancer risk: a systematic review and metaanalysis of randomized controlled trials.
Systematic review and meta-analysis of randomized controlled trials investigating the effect of beta-carotene supplementation on cancer incidence. No overall effect was observed on the incidence of all cancers combined, but increased risk of lung and stomach cancers was noted in smokers and asbestos workers at doses of 20-30 mg/day.
Protection from sunburn with beta-Carotene--a meta-analysis.
Meta-analysis of human supplementation studies on beta-carotene for dietary protection against sunburn. The analysis showed that beta-carotene supplementation protects against sunburn, with effectiveness increasing with longer supplementation duration.
A randomized trial of antioxidant vitamins to prevent second primary cancers in head and neck cancer patients.
A multicenter, double-blind, placebo-controlled, randomized chemoprevention trial among 540 head and neck cancer patients assessed the effect of alpha-tocopherol and beta-carotene supplementation on second primary cancer incidence. Alpha-tocopherol supplementation was associated with a higher rate of second primary cancers during the supplementation period but a lower rate after discontinuation. Overall, alpha-tocopherol produced unexpected adverse effects on cancer occurrence and cancer-free survival.
Randomized trial of antioxidant vitamins to prevent acute adverse effects of radiation therapy in head and neck cancer patients.
Randomized, double-blind, placebo-controlled trial among 540 head and neck cancer patients to assess the effect of alpha-tocopherol and beta-carotene supplementation during radiation therapy. The supplementation reduced the severity of acute adverse effects but did not improve quality of life and might compromise treatment efficacy.
Dietary and serum alpha-tocopherol, beta-carotene and retinol, and risk for colorectal cancer in male smokers.
Prospective cohort study within a randomized, double-blind, placebo-controlled trial testing supplementation with alpha-tocopherol and beta-carotene in preventing cancer among 26,951 male smokers. No significant association was found between dietary or serum levels of antioxidant vitamins and carotenoids and the risk for colorectal cancer.
Randomized trial of supplemental beta-carotene to prevent second head and neck cancer.
RCT of 264 patients with early-stage squamous cell carcinoma of the oral cavity, pharynx, or larynx, testing 50 mg of beta-carotene per day versus placebo for up to 90 months. No significant difference was found in the prevention of second primary tumors or local recurrences, with possible decreased risk for head and neck cancer but increased risk for lung cancer.
Beta-carotene supplementation and incidence of cancer and cardiovascular disease: the Women's Health Study.
The Women's Health Study, a randomized, double-blind, placebo-controlled trial, tested beta-carotene supplementation in 39,876 women aged 45 years or older. The study found no statistically significant differences in the incidence of cancer, cardiovascular disease, or total mortality between the beta-carotene and placebo groups after a median of 4.1 years.
The effects of supplementation with alpha-tocopherol and beta-carotene on the incidence and mortality of carcinoma of the pancreas in a randomized, controlled trial.
RCT of 29,133 male smokers in the ATBC Study evaluating the effects of alpha-tocopherol and beta-carotene supplementation on pancreatic carcinoma incidence and mortality. Beta-carotene supplementation showed a 25% lower incidence rate, while alpha-tocopherol increased incidence by 34%, but neither effect was statistically significant.
Prostate cancer and supplementation with alpha-tocopherol and beta-carotene: incidence and mortality in a controlled trial.
RCT of 29133 male smokers in Finland studying the effects of alpha-tocopherol and beta-carotene supplementation on prostate cancer. Alpha-tocopherol reduced prostate cancer incidence by 32% and mortality by 41%, while beta-carotene increased incidence by 23% and mortality by 15%.
Strategies for recruitment to a population-based lung cancer prevention trial: the CARET experience with heavy smokers. Beta-Carotene and Retinol Efficacy Trial.
The Beta-Carotene and Retinol Efficacy Trial tested the effect of beta-carotene and retinyl palmitate on lung cancer incidence in high-risk smokers. Recruitment involved contacting over 1.2 million households, resulting in 16,449 enrollments and 12,184 randomizations. The study discusses recruitment challenges and reasons for nonparticipation.
Gastric cancer and premalignant lesions in atrophic gastritis: a controlled trial on the effect of supplementation with alpha-tocopherol and beta-carotene. The Helsinki Gastritis Study Group.
RCT within the ATBC study in Finland, involving 1344 older male smokers with atrophic gastritis. The study assessed the effect of alpha-tocopherol and beta-carotene supplementation on gastric neoplasias. Neither supplement showed a significant impact on the prevalence of gastric neoplasias after 5 years.
Randomised trial of alpha-tocopherol and beta-carotene supplements on incidence of major coronary events in men with previous myocardial infarction.
RCT of 1862 men with previous myocardial infarction studying the effect of alpha-tocopherol and beta-carotene supplements on major coronary events. No significant differences in major coronary events were found between supplementation and placebo groups. However, increased risk of fatal coronary heart disease was observed in the beta-carotene and combined supplement groups.
Long-term supplementation with alpha-tocopherol and beta-carotene and age-related cataract.
RCT of 1828 male smokers aged 50-69 years, examining the effect of long-term supplementation with alpha-tocopherol or beta-carotene on cataract prevalence and severity. The study found no association between supplementation and the prevalence or severity of nuclear, cortical, or posterior subcapsular cataracts.
Alpha-Tocopherol and beta-carotene supplements and lung cancer incidence in the alpha-tocopherol, beta-carotene cancer prevention study: effects of base-line characteristics and study compliance.
RCT involving 29,133 male smokers aged 50-69 years, examining the effects of alpha-tocopherol and beta-carotene supplementation on lung cancer incidence. Beta-carotene supplementation was associated with an increased risk of lung cancer, particularly in heavier smokers and those with higher alcohol intake. Alpha-tocopherol showed no overall effect on lung cancer risk.
Risk factors for lung cancer and for intervention effects in CARET, the Beta-Carotene and Retinol Efficacy Trial.
The Beta-Carotene and Retinol Efficacy Trial (CARET) tested the combination of 30 mg beta-carotene and 25,000 IU retinyl palmitate against placebo in 18314 high-risk individuals for lung cancer. The trial was stopped early due to no benefit and potential harm, with 28% more lung cancers and 17% more deaths in the intervention group.
The Linxian trials: mortality rates by vitamin-mineral intervention group.
Two randomized nutrition intervention trials in Linxian, China, assessed the effects of daily supplementation with nutrient combinations in nearly 30,000 participants. Significant reductions in total and cancer mortality were observed in subjects receiving beta-carotene, alpha-tocopherol, and selenium. The reductions were greater in women and those under 55, though differences by sex or age were not significant.
Effects of vitamin/mineral supplementation on the prevalence of histological dysplasia and early cancer of the esophagus and stomach: results from the General Population Trial in Linxian, China.
A randomized nutrition intervention trial in Linxian, China, examined the effects of vitamin/mineral supplementation on esophageal/gastric cancer in a high-risk population. Significant reductions in total mortality, total cancer mortality, and stomach cancer mortality were observed among those receiving beta-carotene, vitamin E, and selenium. No statistically significant reductions in the prevalence of esophageal or gastric dysplasia or cancer were seen for any vitamin/mineral combinations.
Prevention of esophageal cancer: the nutrition intervention trials in Linxian, China. Linxian Nutrition Intervention Trials Study Group.
Two randomized, placebo-controlled nutrition intervention trials in Linxian, China tested the effects of vitamin and mineral supplements on esophageal/gastric cancer rates. The general population trial involved 29,584 adults and tested four nutrient combinations. No significant reductions in cancer prevalence were seen overall, but retinol and zinc reduced gastric cancer prevalence by 62%, and beta-carotene, vitamin E, and selenium reduced esophageal cancer prevalence by 42%.
The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers.
RCT of 29,133 male smokers in Finland testing daily supplementation with alpha-tocopherol, beta carotene, or both for 5-8 years. No reduction in lung cancer incidence was observed with alpha-tocopherol, while beta carotene was associated with a higher incidence of lung cancer. Alpha-tocopherol was associated with fewer prostate cancer cases but more deaths from hemorrhagic stroke. Beta carotene was linked to higher total mortality, primarily due to lung cancer and ischemic heart disease.
Nutrition intervention trials in Linxian, China: supplementation with specific vitamin/mineral combinations, cancer incidence, and disease-specific mortality in the general population.
RCT in Linxian, China, with 29,584 adults receiving daily vitamin and mineral supplementation. The combination of beta carotene, vitamin E, and selenium significantly reduced total mortality and cancer rates, especially stomach cancer. No significant effects were found for other nutrient combinations.
A randomized trial of aspirin and beta-carotene among U.S. physicians.
The Physicians' Health Study is a randomized, placebo-controlled, double-blind clinical trial assessing the effects of aspirin on cardiovascular mortality and beta-carotene on cancer incidence among 22,071 U.S. male physicians. The study uses a 2 x 2 factorial design and is conducted entirely by mail.
Low β-carotene bioaccessibility and bioavailability from high fat, dairy-based meal.
This study investigated the bioavailability of supplemental β-carotene in a high fat, dairy-based meal in a double-blind 3-arm crossover human trial with 7 participants. Despite high doses of β-carotene, there was negligible postprandial response in plasma concentrations. The study explored factors affecting β-carotene bioavailability, including micellisation, fat bioavailability, metabolism to retinol, and food matrix interactions.
Effects of beta-carotene fortified synbiotic food on metabolic control of patients with type 2 diabetes mellitus: A double-blind randomized cross-over controlled clinical trial.
This double-blind randomized crossover controlled clinical trial studied the effects of beta-carotene fortified synbiotic food on metabolic status in 51 patients with type 2 diabetes mellitus. The study found significant improvements in insulin, HOMA-IR, HOMA-B, triglycerides, VLDL-cholesterol, total-/HDL-cholesterol ratio, nitric oxide, and glutathione levels compared to control.
β-Carotene in Golden Rice is as good as β-carotene in oil at providing vitamin A to children.
RCT comparing the vitamin A value of β-carotene in Golden Rice, spinach, and pure β-carotene in oil in children. The study found that β-carotene in Golden Rice is as effective as pure β-carotene in oil and better than that in spinach at providing vitamin A.
beta-Carotene and alpha-tocopherol in healthy overweight adults; depletion kinetics are correlated with adiposity.
RCT with 92 healthy overweight adults using a nutritional product composed of dehydrated juice concentrates. Supplementation increased serum beta-carotene by 264% and alpha-tocopherol by 14%. Depletion rates for beta-carotene correlated with adiposity, with serum half-lives determined for both substances.
Fruit, vegetable, vitamin A intakes, and prostate cancer risk.
Cohort study of 1985 men previously exposed to asbestos, examining prostate cancer risk in relation to intakes of fruit, vegetables, beta-carotene, and retinol. Ninety-seven cases of prostate cancer were identified during follow-up until 2004. A decreased prostate cancer risk was observed with increasing intakes of vitamin C-rich vegetables, while fruit, other vegetables, and vitamin A intakes did not appear to be strong factors.
Low intake of calcium, folate, nicotinic acid, vitamin E, retinol, beta-carotene and high intake of pantothenic acid, biotin and riboflavin are significantly associated with increased genome instability--results from a dietary intake and micronucleus index survey in South Australia.
The study examined the association between dietary intake of various micronutrients and genome damage in lymphocytes using the micronucleus assay in 190 healthy individuals. It found that high intake of vitamin E, retinol, folic acid, nicotinic acid, and calcium reduced genome instability, while high intake of riboflavin, pantothenic acid, and biotin increased it. Beta-carotene showed mixed effects depending on intake level. Supplementation with beta-carotene, vitamins C and E, and zinc reduced genome instability.
Natural beta-carotene for the prevention of post-ERCP pancreatitis.
Double-blind trial assessing the effect of natural beta-carotene on post-ERCP pancreatitis. The incidence of pancreatitis was not significantly different between the beta-carotene and placebo groups, but beta-carotene may reduce the severity of pancreatitis.
Supplementing lactating women with puréed papaya and grated carrots improved vitamin A status in a placebo-controlled trial.
RCT in Zimbabwe with lactating women receiving beta-carotene capsules, puréed papaya, grated carrots, or placebo for 60 days. Serum retinol increased significantly in the beta-carotene, papaya, and carrot groups, but not in the placebo group. The study concludes that puréed papaya and grated carrots can improve vitamin A and iron nutriture.
Effects of three-month oral supplementation of beta-carotene and vitamin C on serum concentrations of carotenoids and vitamins in middle-aged subjects: a pilot study for a randomized controlled trial to prevent gastric cancer in high-risk Japanese population.
Pilot study for an RCT examining the serum response to three-month oral supplementation of beta-carotene and vitamin C in 54 middle-aged subjects. Serum beta-carotene and ascorbic acid levels were significantly higher in high-dose groups compared to placebo. No significant interaction between the supplements was observed, and no unfavorable changes in carotenoids and alpha-tocopherol were noted.
Carotenoids and carotenoids plus vitamin E protect against ultraviolet light-induced erythema in humans.
RCT investigating the protective effects of oral supplementation with carotenoids and a combination of carotenoids and vitamin E against ultraviolet light-induced erythema in humans. Erythema was significantly diminished after 8 weeks, with greater suppression observed with the combination of carotenoids and vitamin E.
Effect of beta-carotene supplementation and lactation on carotenoid metabolism and mitogenic T lymphocyte proliferation.
RCT investigating the effects of short-term beta-carotene supplementation during early lactation on circulating carotenoid concentrations and T lymphocyte proliferation. Beta-carotene supplementation increased beta-carotene and alpha-carotene concentrations but did not affect T lymphocyte proliferative response.
Six-year supplementation with alpha-tocopherol and beta-carotene and age-related maculopathy.
The ATBC study was a controlled clinical trial in Finland involving over 29,000 smoking males aged 50 to 69 years, examining the effects of alpha-tocopherol and beta-carotene supplementation on age-related maculopathy (ARM). An end-of-trial examination of 941 participants found no significant association between the supplements and ARM risk.
Long-term supplementation with alpha-tocopherol and beta-carotene and prevalence of oral mucosal lesions in smokers.
This study assessed the effect of alpha-tocopherol and beta-carotene supplementation on oral mucosal lesions in 409 white male smokers over 5-7 years. No statistically significant differences were found in the prevalence of oral mucosal lesions or in the cells of unkeratinized epithelium between the study groups.
Effect of supplemental beta-carotene on plasma concentrations of carotenoids, retinol, and alpha-tocopherol in humans.
The study assessed the effects of long-term daily supplementation with beta-carotene (50 mg/d) on plasma concentrations of carotenoids, retinol, and alpha-tocopherol in 259 participants. Beta-carotene supplementation resulted in a persistent increase in plasma beta-carotene and alpha-carotene concentrations, but did not affect concentrations of retinol, alpha-tocopherol, lycopene, or lutein/zeaxanthin.
Treatment with 9-cis β-carotene-rich powder in patients with retinitis pigmentosa: a randomized crossover trial.
Randomized, double-masked, placebo-controlled, crossover clinical trial of 9-cis beta-carotene in 34 patients with retinitis pigmentosa. Treatment significantly increased retinal function, with improvements in dark-adapted maximal b-wave amplitude and light-adapted b-wave response. No significant differences were found for visual field and best-corrected visual acuity.
Effects of oral supplementation with β-carotene on concentrations of β-carotene, vitamin A and α-tocopherol in plasma, colostrum and milk of mares and plasma of their foals and on fertility in mares.
RCT studying the effects of oral β-carotene supplementation in mares on β-carotene, vitamin A, and α-tocopherol concentrations in plasma, colostrum, and milk, as well as plasma of their foals. β-carotene concentrations increased in supplemented mares and their foals, but no positive effects on fertility were observed.
Vitamin A equivalency and apparent absorption of beta-carotene in ileostomy subjects using a dual-isotope dilution technique.
A 4-week diet-controlled, cross-over intervention study in 17 healthy adults with an ileostomy quantified the vitamin A equivalency and apparent absorption of beta-carotene using a dual-isotope dilution technique. The study found that the vitamin A equivalency of beta-carotene in oil was 3.6:1, and the apparent absorption from the 'oil diet' was 1.9-fold higher than from the 'mixed diet'.
Intervention study with a high or low antioxidant capacity diet: effects on circulating beta-carotene.
A randomized cross-over intervention trial with 33 healthy participants compared the effects of a high TAC diet versus a low TAC diet on circulating beta-carotene concentrations. The high TAC diet significantly increased circulating beta-carotene levels, suggesting that plasma beta-carotene could be a marker of TAC intake rather than beta-carotene intake itself.
Short-term intake of beta-carotene-supplemented diets enhances ovarian function and progesterone synthesis in goats.
RCT evaluating the effect of beta-carotene supplementation on luteal activity and progesterone synthesis in goats. Beta-carotene-supplemented goats showed higher corpus luteum number and serum progesterone levels, suggesting enhanced ovarian function.
Acute adverse effects of radiation therapy and local recurrence in relation to dietary and plasma beta carotene and alpha tocopherol in head and neck cancer patients.
Prospective study of 540 head and neck cancer patients examining the relationship between dietary and plasma beta carotene and alpha tocopherol with radiation therapy adverse effects and cancer recurrence. Higher dietary beta carotene intake was associated with fewer severe acute adverse effects and lower local cancer recurrence. Alpha tocopherol showed no significant relation.
Supplementation with beta-carotene or a similar amount of mixed carotenoids protects humans from UV-induced erythema.
RCT comparing the erythema-protective effect of beta-carotene (24 mg/d) to a carotenoid mix (beta-carotene, lutein, lycopene) in volunteers with skin type II. Both groups showed increased carotenoid levels in serum and skin, and reduced erythema intensity after 12 weeks of supplementation.
Bioefficacy of beta-carotene dissolved in oil studied in children in Indonesia.
RCT studying the bioefficacy of beta-carotene dissolved in oil in Indonesian children. The study measured isotopic enrichment of beta-carotene and retinol in serum, finding that the conversion efficiency of beta-carotene to retinol was 27% better than previously estimated.
Effects of alpha-tocopherol, beta-carotene and ascorbic acid on oxidative, hormonal and enzymatic exercise stress markers in habitual training activity of professional basketball players.
RCT examining the effects of a vitamin antioxidant supplement (alpha-tocopherol, beta-carotene, ascorbic acid) on oxidative, hormonal, and enzymatic exercise stress markers in 13 professional basketball players over 35 days. Supplementation increased alpha-tocopherol and beta-carotene levels, decreased plasma lipid peroxides by 27.7%, and reduced lactate dehydrogenase activity during recovery.
Effect of long-term beta-carotene and vitamin A on serum cholesterol and triglyceride levels among participants in the Carotene and Retinol Efficacy Trial (CARET).
The study evaluated the effects of long-term supplementation with beta-carotene and retinol on serum triglyceride and cholesterol levels among 52 CARET participants. Results showed a small nonsignificant increase in serum triglyceride levels in the active group during the intervention, and a decrease after stopping the intervention, with no significant changes in cholesterol levels.
Serum retinol concentrations in children are affected by food sources of beta-carotene, fat intake, and anthelmintic drug treatment.
Study in Sumatra, Indonesia, examined the effect of beta-carotene food sources, dietary fat, and deworming on serum retinol concentrations in children aged 3-6 years. Incorporating beta-carotene sources, such as red sweet potatoes, significantly increased serum retinol levels, especially when combined with added dietary fat and deworming treatment.
Short- and long-term beta-carotene supplementation do not influence T cell-mediated immunity in healthy elderly persons.
Two randomized, double-blind, placebo-controlled studies assessed the effects of short-term and long-term beta-carotene supplementation on T cell-mediated immunity in healthy elderly individuals. Both studies found no significant effects of beta-carotene on various immune parameters, including lymphocyte proliferation and cytokine production.
Plasma concentrations of carotenoids after large doses of beta-carotene.
Study measured plasma concentrations of beta-carotene in healthy men ingesting 180 mg beta-carotene daily, focusing on its effects on sunburn prevention and light-sensitive skin diseases. Beta-carotene concentrations plateaued in 1.5 to 4 weeks, with carotenodermia present in most subjects and no evidence of toxicity.
Evaluation of Cellular Absorption and Metabolism of β-Carotene Loaded in Nanocarriers after In Vitro Digestion.
In vitro study on the cellular absorption and metabolism of β-carotene loaded in nanocarriers after digestion. The study found that digestion enhanced the cellular uptake of β-carotene, with whey protein isolate-based carriers improving absorption but decreasing metabolism to retinyl palmitate. Lipids improved metabolism and transport of retinoids.
A Compartmental Model Describing the Kinetics of β-Carotene and β-Carotene-Derived Retinol in Healthy Older Adults.
The study developed a compartmental model to describe the metabolism of β-carotene and β-carotene-derived retinol in healthy older adults. It found that β-carotene absorption was 9.5% and bioefficacy was 7.3%, with significant conversion to retinol and transport in chylomicrons and HDL.
Micro- and nano-encapsulation of β-carotene in zein protein: size-dependent release and absorption behavior.
The study investigates the encapsulation of β-carotene in a zein protein matrix using micro- and nano-encapsulation techniques. It evaluates the impact of particle size on dissolution, release, and absorption behavior, finding that nanoencapsulates show improved dissolution and bioaccessibility compared to microencapsulates.
An LC/MS/MS method for stable isotope dilution studies of β-carotene bioavailability, bioconversion, and vitamin A status in humans[S]
The paper describes the development of a sensitive LC/MS/MS analytical method to study the plasma response from coadministered oral doses of [13C10]β-carotene and [13C10]retinyl acetate in humans over a 2-week period. This method allows for the determination of vitamin A status and bioavailability/bioconversion of provitamin A carotenoids.
Dietary fiber reduces the antioxidative effect of a carotenoid and alpha-tocopherol mixture on LDL oxidation ex vivo in humans.
Cross-over study in six young women examining the effect of dietary fiber on the antioxidative properties of a supplement containing carotenoids and alpha-tocopherol. Dietary fiber reduced the antioxidative effect on LDL oxidation, likely due to decreased bioavailability of the antioxidants.
Reproducibility of erythrocyte polyamine measurements and correlation with plasma micronutrients in an antioxidant vitamin intervention study.
This study assessed the reproducibility of erythrocyte polyamine measurements and their correlation with plasma micronutrients in an antioxidant vitamin intervention study involving beta-carotene and D-alpha-tocopherol acetate. Significant inverse correlations were found between erythrocyte polyamines and plasma levels of various nutrients, suggesting potential biomarker applications in cancer prevention trials.
Discrimination in absorption or transport of beta-carotene isomers after oral supplementation with either all-trans- or 9-cis-beta-carotene.
Human subjects were supplemented with 100 mg beta-carotene per day for 6 days, either as synthetic all-trans-beta-carotene or a natural 50:50 mixture of all-trans- and 6-cis-beta-carotene. Significant increases in plasma concentrations of both isomers were observed, with the all-trans-beta-carotene group showing higher increases. The study demonstrated strong discrimination between the two geometric isomers of beta-carotene.
The Extraction of β-Carotene from Microalgae for Testing Their Health Benefits
Narrative review of methods to extract β-carotene from microalgae and its potential health benefits. Studies show that microalgae extracts containing β-carotene may promote lifespan in lab animals and reduce oxidative stress in culture cells.
Non-Provitamin A and Provitamin A Carotenoids as Immunomodulators: Recommended Dietary Allowance, Therapeutic Index, or Personalized Nutrition?
The paper reviews the immunomodulatory effects of non-provitamin A and provitamin A carotenoids, focusing on β-carotene and lycopene. It discusses the potential adverse effects of high-dose β-carotene supplementation and suggests that lycopene may improve immune functions without increasing cancer risk. The role of retinoic acid in immune modulation and the need for personalized nutrition are highlighted.
Meeting the Vitamin A Requirement: The Efficacy and Importance of β-Carotene in Animal Species
This review discusses the metabolism of β-carotene in various animal species, focusing on its absorption, tissue accumulation, and conversion to vitamin A. It highlights species differences in β-carotene metabolism and the factors affecting its bioavailability and conversion efficiency.