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β-Carotene (beta-carotene) is an organic, strongly colored red-orange pigment abundant in fungi, [7] plants, and fruits. It is a member of the carotenes , which are terpenoids (isoprenoids), synthesized biochemically from eight isoprene units and thus having 40 carbons .
[7] [2] [8] [9] See: Health effects of tobacco smoking and List of cigarette smoke carcinogens. Although many of these additives are used in making cigarettes, each cigarette does not contain all of these additives. Some of these additives are found in cigarettes outside the USA too. [10] Some American brands are sold in other nations.
However, randomized trials like the Beta-Carotene and Retinol Efficacy Trial (CARET) [20] and the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC Study) [21] revealed not only a lack of benefit but an increased risk of cancer, particularly lung cancer among smokers. These findings prompted a reevaluation of antioxidant ...
Long-term use of beta-carotene, vitamin A, and vitamin E supplements may shorten life, [2] and increase the risk of lung cancer in people who smoke (especially those smoking more than 20 cigarettes per day), former smokers, people exposed to asbestos, and those who use alcohol. [21]
Also, some virus are co-carcinogens like Herpesviruses, Epstein–Barr virus (EBV) and human herpesvirus 4 (HHV-4) [9] Over intake beta carotene for a long period of time increased the risk of lung cancer, prostate cancer and many other kind of malignant tumor for cigarette smoker and worker having high contact with asbestos. [10]
High doses of some antioxidants may have harmful long-term effects. The Beta-Carotene and Retinol Efficacy Trial (CARET) study of lung cancer patients found that smokers given supplements containing beta-carotene and vitamin A had increased rates of lung cancer. [140] Subsequent studies confirmed these adverse effects. [141]
β-Carotene is composed of two retinyl groups, and is broken down in the mucosa of the human small intestine by β-carotene 15,15'-monooxygenase to retinal,a form of vitamin A. β-Carotene can be stored in the liver and body fat and converted to retinal as needed, thus making it a form of vitamin A for humans and some other mammals.
This is an accepted version of this page This is the latest accepted revision, reviewed on 7 January 2025. Circumstances, mechanisms, and factors of tobacco consumption on human health "Health effects of smoking" and "Dangers of smoking" redirect here. For cannabis, see Effects of cannabis. For smoking crack cocaine, see Crack cocaine § Health issues. "Smoking and health" redirects here. For ...