Beta-Carotene

by MedlinePlus

The name "carotene" was first coined in the early 19th century by the scientist Wachenroder after he crystallized this compound from carrot roots. Beta-carotene is a member of the carotenoids, which are highly pigmented (red, orange, yellow), fat-soluble compounds naturally present in many fruits, grains, oil and vegetables (green plants, carrots, sweet potatoes, squash, spinach, apricots, and green peppers). Alpha, Beta, and Gamma carotene are considered provitamins because they can be converted to active vitamin A.

The carotenes possess antioxidant properties. Vitamin A serves several biological functions including involvement in the synthesis of certain glycoproteins. Vitamin A deficiency leads to abnormal bone development, disorders of the reproductive system, xerophthalmia (a drying condition of the cornea of the eye), and ultimately death.

Commercially available beta-carotene is produced synthetically or from palm oil, algae, or fungi. Beta-carotene is converted to retinol, which is essential for vision and is subsequently converted to retinoic acid, which is used for processes involving growth and cell differentiation.

Beta-carotene in doses of 20mg daily for 5-8 years has been associated with an increased risk of lung and prostate cancer and increased total mortality in people who smoke cigarettes, and in people with a history of high-level asbestos exposure. Beta-carotene 20-30mg daily in smokers may also increase cardiovascular mortality by 12% to 26%. Therefore, smokers and people with a history of asbestos exposure should not use beta-carotene supplements. These adverse effects do not appear to occur in people who eat foods high in beta-carotene content.

Synonyms

A-Beta-Carotene, alpha carotene, beta carotene, beta-cryptoxanthin, carotene, carotenoids, dry beta carotene, eyebright, gamma carotene, green leafy vegetables, palm oil, provitamin A, red palm oil, sunflower oil, synthetic all-trans beta-carotene, retinol.

Selected proprietary names: A-Caro-25, Arocin, B-Caro, B-Caroteno, B-Tene, BellaCarotin mono, Beta Carotene Capsules USP 27, Betatene, Biocarotine, Biotene, Caroguard, Caro-Plete, Caro-T, Carotaben, Karotena ACO, Lumitene, Marine Carotene, Max-Caro, Mega Carotene, Oceanic Beta, Pervita, Provatene, Provitamin A, Solatene, Superbeta Carotene, Tannisol, Ultra Beta Carotene, Vitaforce Carotene A, Vitcaroten, Zirvit Beta.

Selected multi-ingredient preparations: Aceite Acalorico, Aclon Lievit, Agedin Plus, Angstrom Viso, Antiox, Antioxidant Forte Tablets, Antioxidant Tablets, Apotrin, Beta A-C, Beta-Ace Tablets, Bronsul, Carotin, Cold Sore Tablets, Dexa-Turipol, Difrarel, Difrarel, Ecamannan, Eye Health Herbal Plus Formula 4, Fotoretin, Ginkgo ACE, Jod-Turipol, Karinat, Keratolip, Levudin, Lifesystem Herbal Plus Formula 5 Eye Relief, Lifesystem Herbal Plus Formula 8 Echinacea, Linola gras, Mirtilene, Mirtilus, Odourless Garlic, Oleovit A, Oleovit A + D, Phenoro, Purpuralin, Rilastil Dermo Solar, Seresis, Sinus and Hayfever, Sol Bronce Vital, Solecin, Sonnenbraun, Tannidin Plus, Turipol, Unitone, Visaline.

Also, see Natural Standard information on Vitamin A .

Evidence

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Uses based on scientific evidence

Erythropoietic protoporphyria

Erythropoietic protoporphyria is a rare inherited genetic disorder of porphyrin-heme metabolism which has skin and systemic manifestations, including photosensitivity (painful skin sensitivity to sunlight), as well as gallstones and liver dysfunction. It is usually recognized during childhood. The over-the-counter synthetic beta-carotene product Lumitene is FDA approved for photoprotection in this disease. Effects may take 4-6 weeks to occur. Antihistamines may also be used to reduce symptoms.

Carotenoid deficiency

Although consumption of provitamin A carotenoids (alpha-carotene, beta-carotene, and beta-cryptoxanthin) can prevent vitamin A deficiency, no overt deficiency symptoms have been identified in people consuming low-carotenoid diets if they consume adequate vitamin A. Recommendations by the National Cancer Institute, American Cancer Society, and American Heart Association to consume a variety of fruits and vegetables daily are aimed, in part, at increasing intakes of carotenoid-rich vegetables. After reviewing the published scientific research, the Food and Nutrition Board of the Institute of Medicine (IOM) concluded that the existing evidence in 2000 was insufficient to establish a recommended dietary allowance (RDA) or adequate intake (AI) for carotenoids.

Cataract prevention

Study results of beta-carotene supplementation for cataract prevention are conflicting. Further well-designed clinical trials are needed before a conclusion can be drawn.

Chemotherapy toxicity

Observational research suggests that greater dietary intake of beta-carotene may lower the incidence of adverse effects in children undergoing chemotherapy for lymphoblastic leukemia. However, in theory high-dose antioxidants may interfere with the activity of some chemotherapy drugs or radiation therapy. Therefore, individuals undergoing cancer treatment should speak with their oncologist if they are taking or considering the use of high dose antioxidants. Additional evidence is needed in this area before a clear conclusion can be drawn.

Chronic obstructive pulmonary disease (COPD)

The prevalence of bronchitis and dyspnea in male smokers with chronic obstructive pulmonary disorder (COPD) seems to be lower in those patients who consume a diet containing high amounts of beta-carotene. However, beta-carotene supplements have not been proven to benefit COPD and may actually increase cancer rates in smokers.

Cystic fibrosis

Individuals with cystic fibrosis may be deficient in beta-carotene and vitamin E, and it has been suggested that they may be more susceptible to oxidative damage. Theoretically, these patients may benefit from beta-carotene supplementation. Further research is needed before a conclusion can be drawn. C Exercise-induced asthma prevention

Based on preliminary evidence, taking a mixture of beta-carotene isomers orally may prevent exercise-induced asthma. However, because synthetic beta-carotene has not been well tested for this indication, the difference between the activities of the two supplements cannot be deduced. Further research is needed before a recommendation can be made.

Immune system enhancement

Preliminary research of beta-carotene for immune system maintenance or stimulation shows mixed results. Further research is needed before a conclusion can be drawn.

Macular degeneration

Taking beta-carotene and other antioxidants has been proposed to help prevent or delay progression of age-related macular degeneration. However, other dietary carotenoids such as lycopene, lutein, and zeaxanthin may provide greater protection from radiation and oxidative damage in the retina than beta-carotene. Further research is needed before a conclusion can be drawn.

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