Zeaxanthin

Last updated
Zeaxanthin
Zeaxanthin2.svg
Zeaxanthin molecule spacefill.png
Names
IUPAC name
(3R,3′R)-β,β-Carotene-3,3′-diol
Systematic IUPAC name
(1R,1′R)-4,4′-[(1E,3E,5E,7E,9E,11E,13E,15E,17E)-3,7,12,16-Tetramethyloctadeca-1,3,5,7,9,11,13,15,17-nonaene-1,18-diyl]bis(3,5,5-trimethylcyclohex-3-en-1-ol)
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.005.125 OOjs UI icon edit-ltr-progressive.svg
E number E161h (colours)
PubChem CID
UNII
  • InChI=1S/C40H56O2/c1-29(17-13-19-31(3)21-23-37-33(5)25-35(41)27-39(37,7)8)15-11-12-16-30(2)18-14-20-32(4)22-24-38-34(6)26-36(42)28-40(38,9)10/h11-24,35-36,41-42H,25-28H2,1-10H3/b12-11+,17-13+,18-14+,23-21+,24-22+,29-15+,30-16+,31-19+,32-20+/t35-,36-/m1/s1 Yes check.svgY
    Key: JKQXZKUSFCKOGQ-QAYBQHTQSA-N Yes check.svgY
  • InChI=1/C40H56O2/c1-29(17-13-19-31(3)21-23-37-33(5)25-35(41)27-39(37,7)8)15-11-12-16-30(2)18-14-20-32(4)22-24-38-34(6)26-36(42)28-40(38,9)10/h11-24,35-36,41-42H,25-28H2,1-10H3/b12-11+,17-13+,18-14+,23-21+,24-22+,29-15+,30-16+,31-19+,32-20+/t35-,36-/m1/s1
    Key: JKQXZKUSFCKOGQ-QAYBQHTQBL
  • CC1=C(C(C[C@@H](C1)O)(C)C)/C=C/C(=C/C=C/C(=C/C=C/C=C(/C=C/C=C(/C=C/C2=C(C[C@H](CC2(C)C)O)C)\C)\C)/C)/C
Properties
C40H56O2
Molar mass 568.88 g/mol
Appearanceorange-red
Melting point 215.5 °C (419.9 °F; 488.6 K)
insol.
Related compounds
Related compounds
 lutein
xanthophyll
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

Zeaxanthin is one of the most common carotenoids in nature, and is used in the xanthophyll cycle. Synthesized in plants and some micro-organisms, it is the pigment that gives paprika (made from bell peppers), corn, saffron, goji (wolfberries), and many other plants and microbes their characteristic color. [1] [2]

Contents

The name (pronounced zee-uh-zan'-thin) is derived from Zea mays (common yellow maize corn, in which zeaxanthin provides the primary yellow pigment), plus xanthos, the Greek word for "yellow" (see xanthophyll).

Xanthophylls such as zeaxanthin are found in highest quantity in the leaves of most green plants, where they act to modulate light energy and perhaps serve as a non-photochemical quenching agent to deal with triplet chlorophyll (an excited form of chlorophyll) which is overproduced at high light levels during photosynthesis. [3] Zeaxanthin in guard cells acts as a blue light photoreceptor which mediates the stomatal opening. [4]

Animals derive zeaxanthin from a plant diet. [2] Zeaxanthin is one of the two primary xanthophyll carotenoids contained within the retina of the eye. Zeaxanthin supplements are typically taken on the supposition of supporting eye health. Although there are no reported side effects from taking zeaxanthin supplements, the actual health effects of zeaxanthin and lutein are not proven, [5] [6] [7] and, as of 2018, there is no regulatory approval in the European Union or the United States for health claims about products that contain zeaxanthin.

As a food additive, zeaxanthin is a food dye with E number E161h.

Isomers and macular uptake

Lutein and zeaxanthin have identical chemical formulas and are isomers, but they are not stereoisomers. The only difference between them is in the location of the double bond in one of the end rings. This difference gives lutein three chiral centers whereas zeaxanthin has two. Because of symmetry, the (3R,3′S) and (3S,3′R) stereoisomers of zeaxanthin are identical. Therefore, zeaxanthin has only three stereoisomeric forms. The (3R,3′S) stereoisomer is called meso-zeaxanthin.

The principal natural form of zeaxanthin is (3R,3′R)-zeaxanthin. The macula mainly contains the (3R,3′R)- and meso-zeaxanthin forms, but it also contains much smaller amounts of the third (3S,3′S) form. [8] Evidence exists that a specific zeaxanthin-binding protein recruits circulating zeaxanthin and lutein for uptake within the macula. [9]

Due to the commercial value of carotenoids, their biosynthesis has been studied extensively in both natural products and non-natural (heterologous) systems such as the bacteria Escherichia coli and yeast Saccharomyces cerevisiae. Zeaxanthin biosynthesis proceeds from beta-carotene via the action of a single protein, known as a beta-carotene hydroxylase, that is able to add a hydroxyl group (-OH) to carbon 3 and 3′ of the beta-carotene molecule. Zeaxanthin biosynthesis therefore proceeds from beta-carotene to zeaxanthin (a di-hydroxylated product) via beta-cryptoxanthin (the mono hydroxylated intermediate). Although functionally identical, several distinct beta-carotene hydroxylase proteins are known.

Due to the nature of zeaxanthin, relative to astaxanthin (a carotenoid of significant commercial value) beta-carotene hydroxylase proteins have been studied extensively. [10]

Relationship with diseases of the eye

Several observational studies have provided preliminary evidence for high dietary intake of foods including lutein and zeaxanthin with lower incidence of age-related macular degeneration (AMD), most notably the Age-Related Eye Disease Study (AREDS2). [11] [12] Because foods high in one of these carotenoids tend to be high in the other, research does not separate effects of one from the other. [13] [14]

As for cataracts, two meta-analyses confirm a correlation between high serum concentrations of lutein and zeaxanthin and a decrease in the risk of nuclear cataract, but not cortical or subcapsular cataract. The reports did not separate a zeaxanthin effect from a lutein effect. [19] [20] The AREDS2 trial enrolled subjects at risk for progression to advanced age-related macular degeneration. Overall, the group getting lutein (10 mg) and zeaxanthin (2 mg) did not reduce the need for cataract surgery. [21] Any benefit is more likely to be apparent in subpopulations of individuals exposed to high oxidative stress, such as heavy smokers, alcoholics or those with low dietary intake of carotenoid-rich foods. [22]

In 2005, the US Food and Drug Administration rejected a Qualified Health Claims application by Xangold, citing insufficient evidence supporting the use of a lutein- and zeaxanthin-containing supplement in prevention of AMD. [23] Dietary supplement companies in the U.S. are allowed to sell lutein and lutein plus zeaxanthin products using dietary supplement , such as "Helps maintain eye health", as long as the FDA disclaimer statement ("These statements have not been evaluated...") is on the label. In Europe, as recently as 2014, the European Food Safety Authority reviewed and rejected claims that lutein or lutein plus zeaxanthin improved vision. [24]

Natural occurrence

Zeaxanthin is the pigment that gives paprika, corn, saffron, wolfberries (goji), and many other plants their characteristic colors of red, orange or yellow. [2] [18] Spirulina is also a rich source and can serve as a dietary supplement. [25] Zeaxanthin breaks down to form picrocrocin and safranal, which are responsible for the taste and aroma of saffron. [26]

Dark green leaf vegetables, such as kale, spinach, turnip greens, collard greens, romaine lettuce, watercress, Swiss chard and mustard greens are rich in lutein [2] [27] but contain little to no zeaxanthin, with the exception of scallions cooked in oil. [28] Orange bell peppers (but not green, red, or yellow) are rich in zeaxanthin. [28]

Lutein and zeaxanthin concentrations in fruits and vegetables (µg / 100 g) [28]
Food (100 g)Lutein trans (µg)Zeaxanthin trans (µg)
Spinach, cooked12,6400
Spinach, raw6,6030
Kale, cooked8,8840
Cilantro7,7030
Scallions, cooked in oil2,488
Scallions, raw7820
Bell pepper, green1730
Bell pepper, orange2081,665
Bell pepper, red022
Bell pepper, yellow13918
Cornmeal, yellow1531
Cornmeal, white1313
Corn, cooked from frozen202202
Tortilla, corn276255

Safety

An acceptable daily intake level for zeaxanthin was proposed as 0.75 mg/kg of body weight/day, or 53 mg/day for a 70 kg adult. [29] In humans, an intake of 20 mg/day for up to six months had no adverse effects. [29] As of 2016, neither the U.S. Food and Drug Administration nor the European Food Safety Authority had set a Tolerable Upper Intake Level (UL) for lutein or zeaxanthin.

Related Research Articles

<span class="mw-page-title-main">Carotene</span> Class of compounds

The term carotene (also carotin, from the Latin carota, "carrot") is used for many related unsaturated hydrocarbon substances having the formula C40Hx, which are synthesized by plants but in general cannot be made by animals (with the exception of some aphids and spider mites which acquired the synthesizing genes from fungi). Carotenes are photosynthetic pigments important for photosynthesis. Carotenes contain no oxygen atoms. They absorb ultraviolet, violet, and blue light and scatter orange or red light, and (in low concentrations) yellow light.

<span class="mw-page-title-main">Lycopene</span> Carotenoid pigment

Lycopene is an organic compound classified as a tetraterpene and a carotene. Lycopene is a bright red carotenoid hydrocarbon found in tomatoes and other red fruits and vegetables.

Vitamin E is a group of eight fat soluble compounds that include four tocopherols and four tocotrienols. Vitamin E deficiency, which is rare and usually due to an underlying problem with digesting dietary fat rather than from a diet low in vitamin E, can cause nerve problems. Vitamin E is a fat-soluble antioxidant which may help protect cell membranes from reactive oxygen species. Worldwide, government organizations recommend adults consume in the range of 3 to 15 mg per day. As of 2016, consumption was below recommendations according to a worldwide summary of more than one hundred studies that reported a median dietary intake of 6.2 mg per day for alpha-tocopherol.

Tocopherols are a class of organic compounds comprising various methylated phenols, many of which have vitamin E activity. Because the vitamin activity was first identified in 1936 from a dietary fertility factor in rats, it was named tocopherol, from Greek τόκοςtókos 'birth' and φέρεινphérein 'to bear or carry', that is 'to carry a pregnancy', with the ending -ol signifying its status as a chemical alcohol.

<span class="mw-page-title-main">Vitamin A</span> Essential nutrient

Vitamin A is a fat-soluble vitamin and an essential nutrient for animals. The term "vitamin A" encompasses a group of chemically related organic compounds that includes retinol, retinal, retinoic acid, and several provitamin (precursor) carotenoids, most notably beta-carotene. Vitamin A has multiple functions: it is essential for embryo development and growth, for maintenance of the immune system, and for vision, where it combines with the protein opsin to form rhodopsin – the light-absorbing molecule necessary for both low-light and color vision.

<span class="mw-page-title-main">Cataract</span> Clouding of the lens inside the eye, causing poor vision

A cataract is a cloudy area in the lens of the eye that leads to a decrease in vision of the eye. Cataracts often develop slowly and can affect one or both eyes. Symptoms may include faded colours, blurry or double vision, halos around light, trouble with bright lights, and difficulty seeing at night. This may result in trouble driving, reading, or recognizing faces. Poor vision caused by cataracts may also result in an increased risk of falling and depression. Cataracts cause 51% of all cases of blindness and 33% of visual impairment worldwide.

<span class="mw-page-title-main">Macula</span> Oval-shaped pigmented area near the center of the retina

The macula (/ˈmakjʊlə/) or macula lutea is an oval-shaped pigmented area in the center of the retina of the human eye and in other animals. The macula in humans has a diameter of around 5.5 mm (0.22 in) and is subdivided into the umbo, foveola, foveal avascular zone, fovea, parafovea, and perifovea areas.

<span class="mw-page-title-main">Carotenoid</span> Class of chemical compounds; yellow, orange or red plant pigments

Carotenoids are yellow, orange, and red organic pigments that are produced by plants and algae, as well as several bacteria, archaea, and fungi. Carotenoids give the characteristic color to pumpkins, carrots, parsnips, corn, tomatoes, canaries, flamingos, salmon, lobster, shrimp, and daffodils. Over 1,100 identified carotenoids can be further categorized into two classes – xanthophylls and carotenes.

The National Eye Institute (NEI) is part of the U.S. National Institutes of Health (NIH), an agency of the U.S. Department of Health and Human Services. The mission of NEI is "to eliminate vision loss and improve quality of life through vision research." NEI consists of two major branches for research: an extramural branch that funds studies outside NIH and an intramural branch that funds research on the NIH campus in Bethesda, Maryland. Most of the NEI budget funds extramural research.

β-Carotene Red-orange pigment of the terpenoids class

β-Carotene (beta-carotene) is an organic, strongly colored red-orange pigment abundant in fungi, 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.

<span class="mw-page-title-main">Xanthophyll</span> Chemical compounds subclass

Xanthophylls are yellow pigments that occur widely in nature and form one of two major divisions of the carotenoid group; the other division is formed by the carotenes. The name is from Greek: xanthos (ξανθός), meaning "yellow", and phyllon (φύλλον), meaning "leaf"), due to their formation of the yellow band seen in early chromatography of leaf pigments.

<span class="mw-page-title-main">Multivitamin</span> Dietary supplement containing vitamins

A multivitamin is a preparation intended to serve as a dietary supplement with vitamins, dietary minerals, and other nutritional elements. Such preparations are available in the form of tablets, capsules, pastilles, powders, liquids, or injectable formulations. Other than injectable formulations, which are only available and administered under medical supervision, multivitamins are recognized by the Codex Alimentarius Commission as a category of food.

<span class="mw-page-title-main">Macular degeneration</span> Medical condition associated with vision loss

Macular degeneration, also known as age-related macular degeneration, is a medical condition which may result in blurred or no vision in the center of the visual field. Early on there are often no symptoms. Over time, however, some people experience a gradual worsening of vision that may affect one or both eyes. While it does not result in complete blindness, loss of central vision can make it hard to recognize faces, drive, read, or perform other activities of daily life. Visual hallucinations may also occur.

<span class="mw-page-title-main">Astaxanthin</span> Chemical compound

Astaxanthin is a keto-carotenoid within a group of chemical compounds known as terpenes. Astaxanthin is a metabolite of zeaxanthin and canthaxanthin, containing both hydroxyl and ketone functional groups. It is a lipid-soluble pigment with red coloring properties, which result from the extended chain of conjugated double bonds at the center of the compound. The presence of the hydroxyl functional groups and the hydrophobic hydrocarbons render the molecule amphiphilic.

The Age-Related Eye Disease Study (AREDS) was a clinical trial sponsored by the National Eye Institute that ran from 1992 to 2001. The study was designed to:

<span class="mw-page-title-main">Lutein</span> Yellow organic pigment created by plants

Lutein is a xanthophyll and one of 600 known naturally occurring carotenoids. Lutein is synthesized only by plants, and like other xanthophylls is found in high quantities in green leafy vegetables such as spinach, kale and yellow carrots. In green plants, xanthophylls act to modulate light energy and serve as non-photochemical quenching agents to deal with triplet chlorophyll, an excited form of chlorophyll which is overproduced at very high light levels during photosynthesis. See xanthophyll cycle for this topic.

<span class="mw-page-title-main">Cone dystrophy</span> Medical condition

A cone dystrophy is an inherited ocular disorder characterized by the loss of cone cells, the photoreceptors responsible for both central and color vision.

<span class="mw-page-title-main">Carotenosis</span> Skin discoloration caused by carotenoids

Carotenosis is a benign and reversible medical condition where an excess of dietary carotenoids results in orange discoloration of the outermost skin layer. The discoloration is most easily observed in light-skinned people and may be mistaken for jaundice. Carotenoids are lipid-soluble compounds that include alpha- and beta-carotene, beta-cryptoxanthin, lycopene, lutein, and zeaxanthin. The primary serum carotenoids are beta-carotene, lycopene, and lutein. Serum levels of carotenoids vary between region, ethnicity, and sex in the healthy population. All are absorbed by passive diffusion from the gastrointestinal tract and are then partially metabolized in the intestinal mucosa and liver to vitamin A. From there they are transported in the plasma into the peripheral tissues. Carotenoids are eliminated via sweat, sebum, urine, and gastrointestinal secretions. Carotenoids contribute to normal-appearing human skin color, and are a significant component of physiologic ultraviolet photoprotection.

Capsanthin is a natural red dye of the xanthophyll class of carotenoids. As a food coloring, it has the E number E160c(i). Capsanthin is the main carotenoid in the Capsicum annuum species of plants including red bell pepper, New Mexico chile, and cayenne peppers and a component of paprika oleoresin. Capsanthin is also found in some species of lily. Among other carotenoids, capsanthin is considered to have the greatest antioxidant capacity due to the presence of eleven conjugated double bonds, a conjugated keto group, and a cyclopentane ring.

<i>meso</i>-Zeaxanthin Xanthophyll carotenoid

meso-Zeaxanthin (3R,3´S-Zeaxanthin) is a xanthophyll carotenoid, as it contains oxygen and hydrocarbons, and is one of the three stereoisomers of zeaxanthin. Of the three stereoisomers, meso-zeaxanthin is the second most abundant in nature after 3R,3´R-zeaxanthin, which is produced by plants and algae. To date, meso-zeaxanthin has been identified in specific tissues of marine organisms and in the macula lutea, also known as the "yellow spot", of the human retina.

References

  1. ↑ Encyclopedia.com. "Carotenoids" . Retrieved 6 May 2012.
  2. 1 2 3 4 5 "Lutein + Zeaxanthin Content of Selected Foods". Linus Pauling Institute, Oregon State University, Corvallis. 2014. Retrieved 20 May 2014.
  3. ↑ Bassi, Roberto; Dall'Osto, Luca (2021). "Dissipation of Light Energy Absorbed in Excess: The Molecular Mechanisms". Annual Review of Plant Biology. 72: 47–76. doi: 10.1146/annurev-arplant-071720-015522 . PMID   34143647. S2CID   235480018.
  4. ↑ Kochhar, S. L.; Gujral, Sukhbir Kaur (2020). "Transpiration". Plant Physiology: Theory and Applications (2 ed.). Cambridge University Press. pp. 75–99. doi:10.1017/9781108486392.006. ISBN   978-1-108-48639-2.
  5. ↑ Age-Related Eye Disease Study 2 Research Group (2013). "Lutein + zeaxanthin and omega-3 fatty acids for age-related macular degeneration: The Age-Related Eye Disease Study 2 (AREDS2) randomized clinical trial". JAMA. 309 (19): 2005–15. doi: 10.1001/jama.2013.4997 . PMID   23644932.{{cite journal}}: CS1 maint: numeric names: authors list (link)
  6. ↑ Pinazo-Durán, M. D.; Gómez-Ulla, F; Arias, L; et al. (2014). "Do Nutritional Supplements Have a Role in Age Macular Degeneration Prevention?". Journal of Ophthalmology. 2014: 1–15. doi: 10.1155/2014/901686 . PMC   3941929 . PMID   24672708.
  7. ↑ Koo, E; Neuringer, M; Sangiovanni, J. P. (2014). "Macular xanthophylls, lipoprotein-related genes, and age-related macular degeneration". American Journal of Clinical Nutrition. 100 (Supplement 1): 336S–346S. doi:10.3945/ajcn.113.071563. PMC   4144106 . PMID   24829491.
  8. ↑ Nolan, J. M.; Meagher, K; Kashani, S; Beatty, S (2013). "What is meso-zeaxanthin, and where does it come from?". Eye. 27 (8): 899–905. doi:10.1038/eye.2013.98. PMC   3740325 . PMID   23703634.
  9. ↑ Li, B; Vachali, P; Bernstein, P. S. (2010). "Human ocular carotenoid-binding proteins". Photochemical & Photobiological Sciences. 9 (11): 1418–25. doi:10.1039/c0pp00126k. PMC   3938892 . PMID   20820671.
  10. ↑ Scaife, Mark A.; Ma, Cynthia A.; Ninlayarn, Thanyanun; et al. (22 May 2012). "Comparative Analysis of β-Carotene Hydroxylase Genes for Astaxanthin Biosynthesis". Journal of Natural Products. 75 (6): 1117–24. doi:10.1021/np300136t. PMID   22616944.
  11. ↑ "NIH study provides clarity on supplements for protection against blinding eye disease". US National Eye Institute, National Institutes of Health, Bethesda, MD. 5 May 2013. Archived from the original on 15 August 2019. Retrieved 10 August 2017.
  12. ↑ Bernstein, P. S.; Li, B; Vachali, P. P.; et al. (2015). "Lutein, Zeaxanthin, and meso-Zeaxanthin: The Basic and Clinical Science Underlying Carotenoid-based Nutritional Interventions against Ocular Disease". Progress in Retinal and Eye Research. 50: 34–66. doi:10.1016/j.preteyeres.2015.10.003. PMC   4698241 . PMID   26541886.
  13. 1 2 Krishnadev N, Meleth AD, Chew EY (May 2010). "Nutritional supplements for age-related macular degeneration". Current Opinion in Ophthalmology. 21 (3): 184–9. doi:10.1097/ICU.0b013e32833866ee. PMC   2909501 . PMID   20216418.
  14. ↑ SanGiovanni JP, Chew EY, Clemons TE, et al. (September 2007). "The relationship of dietary carotenoid and vitamin A, E, and C intake with age-related macular degeneration in a case-control study: AREDS Report No. 22". Archives of Ophthalmology . 125 (9): 1225–1232. doi:10.1001/archopht.125.9.1225. PMID   17846363.
  15. ↑ Liu R, Wang T, Zhang B, et al. (2014). "Lutein and zeaxanthin supplementation and association with visual function in age-related macular degeneration". Invest. Ophthalmol. Vis. Sci. 56 (1): 252–8. doi:10.1167/iovs.14-15553. PMID   25515572.
  16. ↑ Wang X, Jiang C, Zhang Y, et al. (2014). "Role of lutein supplementation in the management of age-related macular degeneration: meta-analysis of randomized controlled trials". Ophthalmic Res. 52 (4): 198–205. doi:10.1159/000363327. PMID   25358528. S2CID   5055854.
  17. ↑ Ma L, Dou HL, Wu YQ, et al. (2012). "Lutein and zeaxanthin intake and the risk of age-related macular degeneration: a systematic review and meta-analysis". Br. J. Nutr. 107 (3): 350–9. doi: 10.1017/S0007114511004260 . PMID   21899805.
  18. 1 2 3 Evans, Jennifer R.; Lawrenson, John G. (2023-09-13). "Antioxidant vitamin and mineral supplements for slowing the progression of age-related macular degeneration". The Cochrane Database of Systematic Reviews. 2023 (9): CD000254. doi:10.1002/14651858.CD000254.pub5. ISSN   1469-493X. PMC  10498493. PMID   37702300.
  19. ↑ Liu XH, Yu RB, Liu R, et al. (2014). "Association between lutein and zeaxanthin status and the risk of cataract: a meta-analysis". Nutrients. 6 (1): 452–65. doi: 10.3390/nu6010452 . PMC   3916871 . PMID   24451312.
  20. ↑ Ma L, Hao ZX, Liu RR, et al. (2014). "A dose-response meta-analysis of dietary lutein and zeaxanthin intake in relation to risk of age-related cataract". Graefes Arch. Clin. Exp. Ophthalmol. 252 (1): 63–70. doi:10.1007/s00417-013-2492-3. PMID   24150707. S2CID   13634941.
  21. ↑ Chew EY, SanGiovanni JP, Ferris FL, et al. (2013). "Lutein/zeaxanthin for the treatment of age-related cataract: AREDS2 randomized trial report no. 4". JAMA Ophthalmol. 131 (7): 843–50. doi: 10.1001/jamaophthalmol.2013.4412 . PMC   6774801 . PMID   23645227.
  22. ↑ Fernandez MM, Afshari NA (January 2008). "Nutrition and the prevention of cataracts". Current Opinion in Ophthalmology. 19 (1): 66–70. doi:10.1097/ICU.0b013e3282f2d7b6. PMID   18090901. S2CID   25735519.
  23. ↑ "Letter of Denial - Xangold Lutein Esters, Lutein, or Zeaxanthin and Reduced Risk of Age-related Macular Degeneration or Cataract Formation (Docket No. 2004Q-0180". US FDA, Qualified Health Claims. 19 December 2005.
  24. ↑ "Scientific Opinion on the substantiation of a health claim related to a combination of lutein and zeaxanthin and improved vision under bright light conditions pursuant to Article 13(5) of Regulation (EC) No 1924/2006". EFSA Journal. 12 (7): 3753. 2014. doi: 10.2903/j.efsa.2014.3753 . ISSN   1831-4732.
  25. ↑ Yu, B.; Wang, J.; Suter, P. M.; et al. (2012). "Spirulina is an effective dietary source of zeaxanthin to humans". British Journal of Nutrition. 108 (4): 611–619. doi: 10.1017/S0007114511005885 . PMID   22313576.
  26. ↑ Frusciante, Sarah; Diretto, Gianfranco; Bruno, Mark; et al. (2014-08-19). "Novel carotenoid cleavage dioxygenase catalyzes the first dedicated step in saffron crocin biosynthesis". Proceedings of the National Academy of Sciences. 111 (33): 12246–12251. Bibcode:2014PNAS..11112246F. doi: 10.1073/pnas.1404629111 . ISSN   0027-8424. PMC   4143034 . PMID   25097262.
  27. ↑ "Foods highest in lutein-zeaxanthin per 100 grams". Conde Nast for the USDA National Nutrient Database, release SR-21. 2014. Retrieved 23 December 2015.
  28. 1 2 3 Alisa Perry; Helen Rasmussen; Elizabeth J. Johnson (Feb 2009). "Xanthophyll (lutein, zeaxanthin) content in fruits, vegetables and corn and egg products". Journal of Food Composition and Analysis. 22 (1): 9–15. doi:10.1016/j.jfca.2008.07.006 . Retrieved 4 February 2024.
  29. 1 2 Edwards JA (2016). "Zeaxanthin: Review of Toxicological Data and Acceptable Daily Intake". Journal of Ophthalmology. 2016: 1–15. doi: 10.1155/2016/3690140 . PMC   4738691 . PMID   26885380.
    • In their evaluation of the safety of synthetic zeaxanthin as a Novel Food, the EFSA NDA Scientific Panel [37] applied a 200-fold safety factor to this NOAEL to define an ADI of 0.75 mg/kg bw/day, or 53 mg/day for a 70 kg adult.
    • Formulated zeaxanthin was not mutagenic or clastogenic in a series of in vitro and in vivo tests for genotoxicity.
    • Information from human intervention studies also supports that an intake higher than 2 mg/day is safe, and an intake level of 20 mg/day for up to 6 months was without adverse effect.
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