Articles

Beta-Carotene

Introduction

Beta-carotene belongs to a group of plant compounds called carotenoids. These are the pigments that provide the yellow, orange, and red coloration in fruits and vegetables. Beta-carotene is the most abundant carotenoid in human foods and is generally thought to be the most important carotenoid for humans. Enzymes in the intestines also convert beta-carotene to vitamin A whenever it is needed.

Beta-carotene occurs exclusively in plant (fruit and vegetable) foods. Foods containing high amounts of beta-carotene are green leafy vegetables, carrots, sweet potatoes, squash, spinach, apricots, peaches, cantaloupe, and green, yellow, and red peppers.

Dosage Info

Dosage Range

6-30mg daily, certain medical conditions may warrant significantly higher doses.

Most Common Dosage

6mg (10,000IU) daily.

2mcg beta-carotene (supplement) =
12mcg beta-carotene (dietary) =
1RAE (retinol activity equivalents) = 1mcg retinol

Dosage Forms

Gelatin capsules.

Interactions and Depletions

Interactions

Depletions

Reported Uses

In addition to being a precursor for vitamin A, beta-carotene is an important antioxidant that helps to prevent harmful free radical damage in the body. These effects are believed to be helpful in such diseases as high cholesterol. However, a study involving 153 people with coronary artery disease and low HDL (good) cholesterol questioned these benefits. The antioxidants vitamin C, vitamin E, beta-carotene, and selenium were added to cholesterol treatment of simvastatin and niacin and continued to show improvement over placebo, but decreased the benefits seen on HDL cholesterol measurements from simvastatin and niacin without the antioxidants. (1) Chemotherapy stresses the antioxidant defense system and this could lead to lower antioxidant levels. Increased intake of beta-carotene was found to decrease the risk of toxicity when given to children undergoing chemotherapy. (2)

Another study evaluated beta-carotene with vitamin C and vitamin E in people with cataracts. One hundred and fifty eight patients were followed for three years and used beta-carotene, vitamin C, and vitamin E daily. The use fo these antioxidants delayed the progression of age-related cataracts. (3)

There continues to be a great deal of controversy concerning the role of beta-carotene and different types of cancer. (4) , (5) There is a long past history of an inverse relationship between cancer and beta-carotene. (6) , (7) , (8) , (9) However, the hypotheses formed from reviews of those studies was challenged by Finnish Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study. In this study, beta-carotene was determined to increase the risk of lung cancer and total mortality. In the post-intervention follow-up, it was again concluded that smokers should avoid beta-carotene supplementation. (10) Further controversial findings have surfaced including a study of 45 female and 68 male tobacco smokers. In this study, researchers found a statistically significant reduction plasma levels of various carotenoids, most specifically beta-carotene. (11)

 

Beta-carotene may also enhance immunity by boosting the activity of certain immune fighting agents in the body. (12) It may also offer relief to people who suffer from a genetic disorder, erythropoietic protoporphyria (EPP), that makes them abnormally sensitive to sunlight. (13)

Toxicities & Precautions

Introduction

[span class=alert]Be sure to tell your pharmacist, doctor, or other health care providers about any dietary supplements you are taking. There may be a potential for interactions or side effects.[/span]

Side Effects

Occasional side effects reported with large doses of this dietary supplement include a harmless orange coloring of the skin called carotenosis. (14) It may be necessary to reduce the dose of this dietary supplement or discontinue use to reverse the effect. Tell your doctor if these side effects become severe or do not go away.

Pregnancy / Breast Feeding

To date, the medical literature has not reported any adverse effects related to fetal development during pregnancy or to infants who are breast-fed. Proper nutrition is essential during pregnancy for the healthy development of the fetus. Numerous vitamins and minerals are a vital part of proper nutrition. If you are pregnant, think you might be pregnant, trying to get pregnant, or breast-feeding an infant, talk to your healthcare professional about supplementing your diet with appropriate vitamins and minerals.

Age Limitations

To date, the medical literature has not reported any adverse effects specifically related to the use of this dietary supplement in children. Vitamins and minerals are an essential part of proper growth and development. Talk to your healthcare professional about the appropriate use of vitamins and minerals in children. Do not use any vitamin or mineral in children under 2 years of age unless first discussed with your healthcare professional.

References

  1. View Abstract: Cheung MC, Zhao XQ, Chait A, Albers JJ, Brown BG. Antioxidant supplements block the response of HDL to simvastatin-niacin therapy in patients with coronary artery disease and low HDL. Arterioscler Thromb Vasc Biol. Aug2001;21(8):1320-6.
  2. View Abstract: Kennedy DD, Tucker KL, Ladas ED, Rheingold SR, Blumberg J, Kelly KM. Low antioxidant vitamin intakes are associated with increases in adverse effects of chemotherapy in children with acute lymphoblastic leukemia. Am J Clin Nutr. Jun2004;79(6):1029-36.
  3. View Abstract: Chylack LT Jr, Brown NP, Bron A, Hurst M, Kopcke W, Thien U, Schalch W. The Roche European American Cataract Trial (REACT): a randomized clinical trial to investigate the efficacy of an oral antioxidant micronutrient mixture to slow progression of age-related cataract. Ophthalmic Epidemiol. Feb2002;9(1):49-80.
  4. View Abstract: Paolini M, et al. Beta-carotene: a cancer chemopreventive agent or a co-carcinogen? Mutat Res. Jun2003;543(3):195-200.
  5. View Abstract: Albanes D. Beta-carotene and lung cancer: a case study. Am J Clin Nutr. Jun1999;69(6):1345S-1350S.
  6. View Abstract: Michaud DS, Feskanich D, Rimm EB. Intake of specific carotenoids and risk of lung cancer in 2 prospective US cohorts. Am J Clin Nutr. Oct 2000;72(4):990-7.
  7. View Abstract: Ito Y, Wakai K, Suzuki K, et al. JACC Study Group. Serum carotenoids and mortality from lung cancer: a case-control study nested in the Japan Collaborative Cohort (JACC) study. Cancer Sci. Jan2003;94(1):57-63.
  8. Gaby SK, et al. Vitamin Intake and Health. New York: Marcel Dekker, Inc; 1991:36-39.
  9. View Abstract: Toniolo P, Van Kappel AL, Akhmedkhanov A, et al. Serum carotenoids and breast cancer. Am J Epidemiol. Jun2001;153(12):1142-7.
  10. View Abstract: Virtamo J, et al. Incidence of cancer and mortality following alpha-tocopherol and beta-carotene supplementation: a postintervention follow-up. JAMA. Jul2003;290(4):476-85.
  11. View Abstract: Lagiou P, et al. Plasma carotenoid levels in relation to tobacco smoking and demographic factors. Int J Vitam Nutr Res. May2003;73(3):226-31
  12. Race TF, et al. Intestinal Malabsorption Induced by Oral Colchicine. Comparison with Neomycin and Cathartic Agents. Am J Med Sci. Jan1970;259(1):32-41.
  13. View Abstract: Mathews-Roth MM, et al. Beta Carotene Therapy for Erythropoietic Protoporphyria and Other Photosensitivity Diseases. Arch Dermatol. Sept1977;113(9):1229-32.
  14. View Abstract: Nishimura Y, Ishii N, Sugita Y. A case of carotenodermia caused by a diet of the dried seaweed called Nori. J Dermatol. Oct1998;25(10):685-7.