Carotene extract
Also known as: Carotene extract, provitamin A carotenoid, carotenoid extract, Beta-carotene
Overview
Carotene extract primarily refers to extracts rich in carotenoids, especially beta-carotene (C40H56), which is a precursor of vitamin A. It is a fat-soluble pigment found naturally in colorful fruits and vegetables like carrots, sweet potatoes, and spinach. As a dietary supplement, carotene extract is used to enhance antioxidant capacity, support vision, and promote skin health, acting as a provitamin A source. It is also studied for its potential role in mitigating oxidative stress and reducing the risk of chronic diseases. Beta-carotene functions as a lipophilic antioxidant and is enzymatically converted to vitamin A in the body, playing a crucial role in modulating oxidative stress markers. Research on beta-carotene is extensive, with numerous randomized controlled trials and meta-analyses exploring its effects on mortality, cardiovascular disease, and oxidative stress, though findings are mixed regarding its benefits and risks.
Benefits
Carotenoid supplementation significantly increases antioxidative capacity markers such as ferric-reducing ability of plasma (FRAP) and oxygen radical absorbance capacity (ORAC), with standardized mean differences (SMD) around 0.37–0.57, indicating a moderate enhancement of antioxidant status (p < 0.01). This effect is observed in general adult populations. While dietary or circulating beta-carotene levels are inversely associated with all-cause mortality risk in observational studies, suggesting a protective effect from natural intake, supplementation with beta-carotene has not shown a significant reduction in all-cause mortality (risk ratio ~1.02, 95% CI 0.98–1.05). In some populations, particularly smokers, supplementation may even slightly increase cardiovascular incidence and mortality risk (RR 1.04–1.12). Antioxidant benefits from supplementation can be seen within weeks to months, but long-term effects on mortality and cardiovascular disease risk remain inconclusive or potentially harmful.
How it works
Beta-carotene functions primarily as an antioxidant by quenching singlet oxygen and scavenging free radicals, thereby protecting cells from oxidative damage. It is also a provitamin A carotenoid, meaning it can be enzymatically converted into retinol (vitamin A) within the body. Vitamin A is essential for various physiological processes, including vision, immune system function, and cellular differentiation. Beta-carotene interacts with body systems by modulating oxidative stress pathways, supporting immune responses, and influencing cardiovascular health markers. Its known molecular targets include reactive oxygen species (ROS) and lipid peroxidation pathways, and it indirectly affects retinoid receptors through its conversion to vitamin A. As a fat-soluble compound, its absorption is enhanced by dietary fat and bile salts, with bioavailability varying based on the food matrix and supplement formulation.
Side effects
Carotene extract is generally safe when consumed at dietary levels. However, high-dose supplementation, particularly in smokers, has been linked to an increased risk of lung cancer and cardiovascular mortality. Common side effects are rare at typical doses, but mild gastrointestinal discomfort can occasionally occur. A more noticeable, though uncommon (1-5%), side effect of high intake is carotenodermia, which causes a benign yellowing of the skin. Rarely (<1%), very high doses, especially in smokers, may exhibit pro-oxidant effects. Beta-carotene may interact with cholesterol-lowering drugs, affecting its absorption, and caution is advised when used concurrently with retinoid medications. High-dose beta-carotene supplements are contraindicated for smokers and individuals exposed to asbestos due to the increased risk of cancer. Pregnant women should avoid excessive doses, and children require lower, carefully monitored dosages.
Dosage
For antioxidant effects, a minimum effective dose of approximately 6–20 mg/day of beta-carotene equivalent has been observed. Optimal dosage ranges for supplementation typically fall between 6–15 mg/day. Doses exceeding 20 mg/day have been linked to adverse effects in certain groups, particularly smokers, and caution is advised above this level. The maximum safe dose is not definitively established for all populations, but upper intake levels vary, and exceeding 20 mg/day should be approached with caution. Beta-carotene should be taken with meals containing fat to enhance its absorption, as it is a fat-soluble compound. Both natural extracts and synthetic beta-carotene capsules are available, with natural sources often preferred for their broader spectrum of carotenoids and perceived safety. Absorption can be reduced by high fiber intake and certain medications. Adequate fat intake is a required cofactor for optimal absorption, and synergistic effects may be observed with other antioxidants like vitamin E.
FAQs
Does beta-carotene supplementation reduce mortality?
No, meta-analyses indicate no significant reduction in all-cause mortality with beta-carotene supplementation, and some studies suggest a slight increase in mortality risk.
Is carotene extract safe for smokers?
No, high-dose beta-carotene supplements are not safe for smokers, as they have been linked to an increased risk of lung cancer and cardiovascular mortality.
How long before benefits appear?
Improvements in antioxidant markers can be observed within weeks of supplementation, but long-term clinical benefits on disease outcomes are unproven or potentially negative.
Is natural dietary intake better than supplements?
Yes, observational studies show that dietary beta-carotene intake is inversely associated with all-cause mortality, a benefit not consistently seen with supplementation.
Can carotene extract cause toxicity?
Toxicity is rare; skin yellowing (carotenodermia) is a benign side effect. However, very high doses in susceptible groups, like smokers, may lead to harmful pro-oxidant effects.
Research Sources
- https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2022.872310/full – This meta-analysis of randomized controlled trials found that beta-carotene supplements had no preventive effect on mortality, with a risk ratio of 1.02 (95% CI 0.98–1.05). Subgroup analyses consistently showed no benefit, highlighting the lack of mortality reduction from supplementation.
- https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2022.754707/full – This meta-analysis of RCTs demonstrated that carotenoid supplementation significantly increased antioxidant capacity markers (FRAP and ORAC) with standardized mean differences ranging from 0.37 to 0.57 (p<0.01). The study included 5-8 trials per antioxidant marker and showed consistent effects on these biomarkers.
- https://pubmed.ncbi.nlm.nih.gov/35334942/ – This systematic review and meta-analysis of 10 trials involving 182,788 individuals found that beta-carotene supplementation slightly increased cardiovascular incidence (RR 1.04) and mortality (RR 1.12), particularly in smokers. The study used rigorous methods and a large sample size, but noted heterogeneity in populations.
- https://www.nature.com/articles/srep26983 – This meta-analysis of prospective observational studies reported an inverse association between dietary and circulating beta-carotene levels and all-cause mortality risk. While providing moderate evidence from observational data, it suggests a protective effect from natural intake, distinct from supplementation.
Supplements Containing Carotene extract
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