Carotene - China Car Body Sticker - China Childrens Wall Stickers
Dietary sources
Dietary sources
The following foods are particularly rich in carotenes (also see Vitamin A article for amounts):
sweet potatoes
carrots
wolfberries (goji)
cantaloupe melon
mangoes
apricots
Persimmon
spinach
kale
chard
turnip greens
dandelion greens
beet greens
mustard greens
collard greens
watercress
cilantro
fresh thyme
broccoli
parsley
romaine lettuce
ivy gourd
rose hips
winter squash
pumpkin
cassava
Absorption from these foods is enhanced if eaten with fats, as carotenes are fat soluble, and if the food is cooked for a few minutes until the plant cell wall splits and the colour is released into any liquid. 6 g of dietary -carotene supplies the equivalent of 1 g of retinol, or 1 RE (Retinol Equivalent). This is equivalent to 3 IU of vitamin A.
The multiple forms
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-carotene
-carotene
The two primary isomers of carotene, -carotene and -carotene, differ in the position of double bonds in the cyclic group at the end.
-Carotene is the more common form and can be found in yellow, orange, and green leafy fruits and vegetables. As a rule of thumb, the greater the intensity of the orange colour of the fruit or vegetable, the more -carotene it contains.
Carotene protects plant cells against the destructive effects of ultraviolet light. -Carotene is an anti-oxidant.
-Carotene and cancer
It has been shown in trials that the ingestion of -carotene at about 30mg/day (10 times the Reference Daily Intake) increases the rate of lung cancer and prostate cancer in smokers and people with a history of asbestos exposure.[citation needed]
An article on the American Cancer Society says that The Cancer Research Campaign has called for warning labels on -carotene supplements to caution smokers that such supplements may increase the risk of lung cancer.
The New England Journal of Medicine published an article in 1994 about a trial which examined the relationship between daily supplementation of -carotene and vitamin E (alpha-tocopherol) and the incidence of lung cancer. The study was done using supplements and researchers were aware of the epidemiological correlation between carotenoid-rich fruits and vegetables and lower lung cancer rates. The research concluded that no reduction in lung cancer was found in the participants using these supplements, and furthermore, these supplements may, in fact, have harmful effects.
The Journal of the National Cancer Institute and The New England Journal of Medicine published articles in 1996 about a trial that was conducted to determine if vitamin A (in the form of retinyl palmitate) and -carotene had any beneficial effects to prevent cancer. The results indicated an increased risk of lung cancer for the participants who consumed the -carotene supplement and who had lung irritation from smoking or asbestos exposure, causing the trial to be stopped early.
A review of all randomized controlled trials in the scientific literature by the Cochrane Collaboration published in JAMA in 2007 found that -carotene increased mortality by something between 1 and 8% (Relative Risk 1.05, 95% confidence interval 1.01-1.08). However, this meta-analysis included two large studies of smokers, so it is not clear that the results apply to the general population.
-Carotene and cognition
A recent report demonstrated that 50mg of -carotene every other day prevented cognitive decline in a study of over 4000 physicians at a mean treatment duration of 18 years.
-Carotene and photosensitivity
Oral -carotene is prescribed to people suffering from erythropoietic protoporphyria. It provides them some relief from photosensitivity.[citation needed]
-Carotene and nanotechnology
-Carotene and lycopene molecules can be encapsulated into carbon nanotubes enhancing the optical properties of carbon nanotubes . Efficient energy transfer occurs between the encapsulated dye and nanotube light is absorbed by the dye and without significant loss is transferred to the SWCNT. Encapsulation increases chemical and thermal stability of carotene molecules; it also allows their isolation and individual characterization .
Carotenemia
Main article: Carotenodermia
Carotenemia or hypercarotenemia is excess carotene, but unlike excess vitamin A, carotene is non-toxic. Although hypercarotenemia is not particularly dangerous, it can lead to an oranging of the skin (carotenodermia), but not the conjunctiva of eyes (thus easily distinguishing it visually from jaundice). It is most commonly associated with consumption of an abundance of carrots, but it also can be a medical sign of more dangerous conditions.
Production
Most of the world's synthetic supply of carotene comes from a manufacturing complex located in Freeport, Texas and owned by DSM.[citation needed] The other major supplier BASF[citation needed] also uses a chemical process to produce -carotene. Together these suppliers account for about 85% of the -carotene on the market.[citation needed] In Spain Vitatene produces natural -carotene from fungus Blakeslea trispora, as does DSM but at much lower amount when compared to its synthetic -carotene operation. In Australia, organic -carotene is produced by Aquacarotene Limited from dried marine algae Dunaliella salina grown in harvesting ponds situated in Karratha, Western Australia. Cognis Australia Pty. Ltd., a subsidiary of the Germany-based company Cognis, is also producing -carotene from microalgae grown in two sites in Australia that are the world largest algae farms. In Portugal, the industrial biotechnology company Biotrend is producing natural all-trans--carotene from a non genetically modified bacteria of the Sphingomonas genus isolated from soil.
Carotenes are also found in palm oil, corn, and in the milk of dairy cows,[citation needed] causing cow's milk to be light yellow, depending on the feed of the cattle, and the amount of fat in the milk (high-fat milks, such as those produced by Guernsey cows, tend to be more yellow because their fat content causes them to contain more carotene).
Carotenes are also found in some species of termites, where they apparently have been picked up from the diet of the insects.[citation needed]
Total synthesis
There are currently two commonly used methods of total synthesis of -carotene. The first was developed by the Badische Anilin- & Soda-Fabrik (BASF) and is based on the Wittig reaction with Wittig himself as patent holder :
The second is a Grignard reaction,[citation needed] elaborated by Hoffman-La Roche from the original synthesis of Inhoffen et al. They are both symmetrical; the BASF synthesis is C20 + C20 , and the Hoffman-La Roche synthesis is C19 + C2 + C19.
Nomenclature
Carotenes are carotenoids containing no oxygen. Carotenoids containing some oxygen are known as xanthophylls.
The two ends of the -carotene molecule are structurally identical, and are called -rings. Specifically, the group of nine carbon atoms at each end form a -ring.
The -carotene molecule has a -ring at one end; the other end is called an -ring. There is no such thing as an "-ring".
These and similar names for the ends of the carotenoid molecules form the basis of a systematic naming scheme, according to which:
-carotene is ,-carotene;
-carotene is ,-carotene;
-carotene (with one ring and one uncyclized end that is labelled psi) is ,-carotene;
-carotene (with one ring and one uncyclized end) is ,-carotene;
-carotene is ,-carotene
lycopene is ,-carotene
-carotene is the biosynthetic precursor of neurosporene, which is the precursor of lycopene, which, in turn, is the precursor of the carotenes through . comes first.[vague]
See also
Antioxidant
Phytonutrients
References
^ Linus Pauling Institute. "Micronutrient Information Center: Carotenoids". http://lpi.oregonstate.edu/infocenter/phytochemicals/carotenoids/. Retrieved February 15, 2010.
^ a b c d e f g h i j What can foods rich in beta-carotene do for you?
^ a b c d e f g h i j k l m n Pitchford, Paul (2002). Healing with Whole Foods: Asian Traditions and Modern Nutrition. North Atlantic Books. ISBN 1-55-643471-5.
^ Ajila CM, Prasada Rao UJ (2008). "Determination of carotenoids and their esters in fruits of Lycium barbarum Linnaeus by HPLC-DAD-APCI-MS". J Pharm Biomed Anal 47 (4-5): 812-8. PMID 18486400.
^ James Allen Olson, PhD, Iowa State University (deceased) Cheryl L. Rock, PhD, University of California, San Diego A. Catharine Ross, PhD, The Pennsylvania State University Barbara A. Underwood, PhD (2006-04-23). "Dietary Supplement Fact Sheet: Vitamin A". NIH Office of Dietary Supplements website. United States Department of Agriculture. http://ods.od.nih.gov/factsheets/vitamina.asp. Retrieved 2007-10-26.
^ a b World's Healthiest Foods: Carotenoids
^ WHFoods: Mustard greens
^ Artemis P. Simopoulos and C. Gopalan, ed. (2003). Plants in Human Health and Nutrition Policy. Karger Publishers. ISBN 3-80-557554-8.
^ Rose Hips
^ Carotenoids in cassava: comparison of open-column and HPLC methods of analysis.
^ "British Cancer Organization Calls for Warning Labels on Beta-Carotene". 2000-07-31. http://www.cancer.org/docroot/NWS/content/NWS_1_1x_Warning_Labels_on_Beta_Carotene_Called_For.asp. Retrieved 2007-03-15.
^ The Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group (1994). "The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers". N Engl J Med. 330 (15): 102935. doi:10.1056/NEJM199404143301501. PMID 8127329.
^ Omenn GS, Goodman GE, Thornquist MD, et al. (1996). "Risk factors for lung cancer and for intervention effects in CARET, the Beta-Carotene and Retinol Efficacy Trial". J Natl Cancer Inst. 88 (21): 15509. doi:10.1093/jnci/88.21.1550. PMID 8901853. http://jncicancerspectrum.oxfordjournals.org/cgi/content/abstract/jnci;88/21/1550.
^ a b Omenn GS, Goodman GE, Thornquist MD, et al. (1996). "Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease". N Engl J Med. 334 (18): 11505. doi:10.1056/NEJM199605023341802. PMID 8602180. http://content.nejm.org/cgi/content/abstract/334/18/1150.
^ Bjelakovic G, Nikolova D, Gluud LL, Simonetti RG, Gluud C (2007). "Mortality in randomized trials of antioxidant supplements for primary and secondary prevention: systematic review and meta-analysis". JAMA 297 (8): 84257. doi:10.1001/jama.297.8.842. PMID 17327526. http://jama.ama-assn.org/cgi/content/abstract/297/8/842.
^ See the letter to JAMA by Philip Taylor and Sanford Dawsey and the reply by the authors of the original paper.
^ Grodstein F, Kang JH, Glynn RJ, Cook NR, Gaziano JM (Nov 2007). "A randomized trial of beta carotene supplementation and cognitive function in men: the Physicians' Health Study II". Arch Intern Med. 167 (20): 218490. doi:10.1001/archinte.167.20.2184. PMID 17998490.
^ K. Yanagi et al. (2006). "Light-Harvesting Function of -Carotene Inside Carbon Nanotubes". Phys. Rev. B 74: 155420. doi:10.1103/PhysRevB.74.155420.
^ Y. Saito et al. (2006). "Vibrational Analysis of Organic Molecules Encapsulated in Carbon Nanotubes by Tip-Enhanced Raman Spectroscopy". Jap. J. Appl. Phys. 45: 92869289. doi:10.1143/JJAP.45.9286.
^ Wittig G.; Pommer H.: DBP 954247, 1956
^ Wittig G.; Pommer H.: Chem. Abstr. 1959, 53, 2279
External links
-Carotene website by Martha Evens, School of Chemistry, University of Bristol
Berkeley Wellness Guide to Dietary Supplements
-Carotene on University of Maryland Medical Center
World's Healthiest Foods: carotenoids
MeSH Carotene
vde
Types of Plant pigments
Flavonoids
Anthocyanins Anthocyanidins Anthoxanthins Proanthocyanidins Tannins
Betalains
Betacyanins Betaxanthins
Carotenoids
Xanthophylls Carotenes Retinoids
Other
Chlorophyll (a, b, c1, c2, d) Allophycocyanin Phycocyanin Phycoerythrin Phycoerythrocyanin Quinones Xanthones
vde
Carotenoids
Carotenes (C40)
-Carotene -Carotene -Carotene -Carotene -Carotene -Carotene Lycopene Neurosporene Phytoene Phytofluene
Xanthophylls (C40)
Antheraxanthin Astaxanthin Canthaxanthin Citranaxanthin Cryptoxanthin Diadinoxanthin Diatoxanthin Dinoxanthin Flavoxanthin Fucoxanthin Lutein Neoxanthin Rhodoxanthin Rubixanthin Violaxanthin Zeaxanthin
Apocarotenoids (C
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