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Lutein

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This is an old revision of this page, as edited by Sbharris (talk | contribs) at 03:27, 24 October 2012 (Blue light is not ionizing (though it can create free radicals and ROS). Merriam's doesn't say this, and even if it did, this is a science fact, not something a dictonary is useful for). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Lutein
Names
IUPAC name
β,ε-carotene-3,3'-diol
Other names
Luteine; trans-lutein; 4-​[18-​(4-​Hydroxy-​2,6,6-​trimethyl-​1-​cyclohexenyl)-​3,7,12,16-​tetramethyloctadeca-​1,3,5,7,9,11,13,15,17-​nonaenyl]-​3,5,5-​trimethyl-​cyclohex-​2-​en-​1-​ol
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.004.401 Edit this at Wikidata
E number E161b (colours)
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/h11-25,35-37,41-42H,26-28H2,1-10H3/b12-11+,17-13+,18-14+,23-21+,24-22+,29-15+,30-16+,31-19+,32-20+/t35-,36+,37-/m0/s1 checkY
    Key: KBPHJBAIARWVSC-RGZFRNHPSA-N checkY
  • Key: KBPHJBAIARWVSC-RGZFRNHPBY
  • Key: KBPHJBAIARWVSC-RGZFRNHPSA-N
  • 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)/C=C/[C@H]2C(=C[C@@H](CC2(C)C)O)C)/C)/C
Properties
C40H56O2
Molar mass 568.871 g/mol
Appearance Red-orange crystalline solid
Melting point 190 °C[1]
Insoluble
Solubility in fats Soluble
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Lutein (/[invalid input: 'icon']ˈluːti.[invalid input: 'ɨ']n/ or /ˈluːtiːn/;[2] from Latin luteus meaning "yellow") 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 and kale. 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.

Lutein is obtained by animals directly or indirectly, from plants. Lutein is apparently[citation needed] employed by animals as an antioxidant and for blue light absorption. Lutein is found in egg yolks and animal fats. In addition to coloring yolks, lutein causes the yellow color of chicken skin and fat, and is used in chicken feed for this purpose. The human retina accumulates lutein and zeaxanthin. The latter predominates at the macula lutea while lutein predominates elsewhere in the retina. There, it may serve as a photoprotectant for retina from the damaging effects of free radicals produced by blue light.

The principal natural stereoisomer of lutein is (3R,3′R,6′R)-beta,epsilon-carotene-3,3′-diol. Lutein is a lipophilic molecule and is generally insoluble in water. The presence of the long chromophore of conjugated double bonds (polyene chain) provides the distinctive light-absorbing properties. The polyene chain is susceptible to oxidative degradation by light or heat and is chemically unstable in acids.

Lutein is present in plants as fatty-acid esters, with one or two fatty acids bound to the two hydroxyl-groups. For this reason, saponification (de-esterfication) of lutein esters to yield free lutein may yield lutein in any ratio from 1:1 to 1:2 molar ratio with the saponifying fatty acid.

Lutein is isomeric with zeaxanthin, differing only in the placement of one double bond.

As a pigment

This xanthophyll, like its sister compound zeaxanthin, has primarily been used as a natural colorant due to its orange-red color. Lutein absorbs blue light and therefore appears yellow at low concentrations and orange-red at high concentrations.

Lutein was traditionally used in chicken feed to provide the yellow color of broiler chicken skin. Polled consumers viewed yellow chicken skin more favorably than white chicken skin. Such lutein fortification also results in a darker yellow egg yolk. Today the coloring of the egg yolk has become the primary reason for feed fortification. Lutein is not used as a colorant in other foods due to its limited stability, especially in the presence of other dyes.

Role in human eyes

Lutein was found to be concentrated in the macula, a small area of the retina responsible for central vision. The hypothesis for the natural concentration is that lutein helps keep the eyes safe from oxidative stress and the high-energy photons of blue light. Various research studies have shown that a direct relationship exists between lutein intake and pigmentation in the eye.[3][4][5][6][7][8][9]

Lutein may play a role in Haidinger's brush, an entoptic phenomenon that allows humans to detect polarized light.

Macular degeneration

Several studies show that an increase in macula pigmentation decreases the risk for eye diseases such as age-related macular degeneration (AMD).[10][11][12] The only randomized clinical trial to demonstrate a benefit for lutein in macular degeneration was a small study, in which the authors concluded that visual function is improved with lutein alone or lutein together with other nutrients and also that more study was needed .[11]

There is epidemiological evidence of a relationship between low plasma concentrations of lutein and zeaxanthin, and an increased risk of developing age-related macular degeneration (AMD). Some studies support the view that supplemental lutein and/or zeaxanthin help protect against AMD.[13]

In 2007, in a 6-year study, John Paul SanGiovanni of the National Eye Institute, Maryland found that lutein and zeaxanthin (nutrients in eggs, spinach and other green vegetables) protect against blindness (macular degeneration), affecting 1.2 million Americans, mostly after age 65. Lutein and zeaxanthin reduce the risk of AMD.[13]

Cataracts

There is also epidemiological evidence that increasing lutein and zeaxanthin intake lowers the risk of cataract development.[13][14] Consumption of more than 2.4 mg of lutein/zeaxanthin daily from foods and supplements was significantly correlated with reduced incidence of nuclear lens opacities, as revealed from data collected during a 13- to 15-year period in the Nutrition and Vision Project (NVP).[15]

Photophobia (abnormal human optical light sensitivity)

A study by Stringham and Hammond, published in the Jan-Feb issue of Journal of Food Science, discusses the improvement in visual performance and decrease in light sensitivity (glare) in subjects taking 10 mg lutein and 2 mg zeaxanthin per day.[16]

In nutrition

Lutein is a natural part of human diet when fruits and vegetables are consumed. For individuals lacking sufficient lutein intake, lutein-fortified foods are available, or in the case of elderly people with a poorly absorbing digestive system, a sublingual spray is available. As early as 1996, lutein has been incorporated into dietary supplements. While no recommended daily allowance currently exists for lutein as for other nutrients, positive effects have been seen at dietary intake levels of 6–10 mg/day.[17] The only definitive side effect of excess lutein consumption is bronzing of the skin (carotenodermia).

The functional difference between lutein (free form) and lutein esters is not entirely known. It is suggested that the bioavailability is lower for lutein esters, but much debate continues.[18]

As a food additive, lutein has the E number E161b (INS number 161b) and is extracted from the petals of marigold (Tagetes erecta).[19] It is approved for use in the EU[20] and Australia and New Zealand[21] however is banned in the USA.[citation needed]

Some foods are considered good sources of the nutrients:[22][13][23][24]

Product Lutein/zeaxanthin (micrograms per hundred grams)
nasturtium (yellow flowers, lutein levels only) 45000
kale (raw) 39550
kale (cooked) 18246
dandelion leaves (raw) 13610
nasturtium (leaves, lutein levels only) 13600
turnip greens (raw) 12825
spinach (raw) 12198
spinach (cooked) 11308
swiss chard (raw or cooked) 11000
turnip greens (cooked) 8440
collard greens (cooked) 7694
watercress (raw) 5767
garden peas (raw) 2593
romaine lettuce 2312
zucchini 2125
brussels sprouts 1590
pistachio nuts 1205
broccoli 1121
carrot (cooked) 687
Maize/corn 642
egg (hard boiled) 353
carrot (raw) 256
kiwifruit 122

Commercial value

The lutein market is segmented into pharmaceutical, nutraceutical, food, pet foods, and animal and fish feed. The pharmaceutical market is estimated to be about US $190 million, nutraceutical and food is estimated to be about US $110 million. Pet foods and other applications are estimated at US $175 million annually. Apart from the customary age-related macular degeneration applications, newer applications are emerging in cosmetics, skins and as an antioxidant. It is one of the fastest growing areas of the US $2 billion carotenoid market.[25]

See also

References

  1. ^ MSDS at Carl Roth (Lutein Rotichrom, German).
  2. ^ Merriam-Webster's Online Dictionary, OED
  3. ^ Malinow MR, Feeney-Burns L, Peterson LH, Klein ML, Neuringer M (1980). "Diet-related macular anomalies in monkeys". Invest. Ophthalmol. Vis. Sci. 19 (8): 857–63. PMID 7409981. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  4. ^ Johnson EJ, Hammond BR, Yeum KJ; et al. (2000). "Relation among serum and tissue concentrations of lutein and zeaxanthin and macular pigment density". Am. J. Clin. Nutr. 71 (6): 1555–62. PMID 10837298. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  5. ^ Landrum, J., et al. Serum and macular pigment response to 2.4 mg dosage of lutein. in ARVO. 2000.
  6. ^ Berendschot TT, Goldbohm RA, Klöpping WA, van de Kraats J, van Norel J, van Norren D (2000). "Influence of lutein supplementation on macular pigment, assessed with two objective techniques". Invest. Ophthalmol. Vis. Sci. 41 (11): 3322–6. PMID 11006220. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  7. ^ Aleman TS, Duncan JL, Bieber ML; et al. (2001). "Macular pigment and lutein supplementation in retinitis pigmentosa and Usher syndrome". Invest. Ophthalmol. Vis. Sci. 42 (8): 1873–81. PMID 11431456. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  8. ^ Duncan JL, Aleman TS, Gardner LM; et al. (2002). "Macular pigment and lutein supplementation in choroideremia". Exp. Eye Res. 74 (3): 371–81. doi:10.1006/exer.2001.1126. PMID 12014918. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  9. ^ Johnson EJ, Neuringer M, Russell RM, Schalch W, Snodderly DM (2005). "Nutritional manipulation of primate retinas, III: Effects of lutein or zeaxanthin supplementation on adipose tissue and retina of xanthophyll-free monkeys". Invest. Ophthalmol. Vis. Sci. 46 (2): 692–702. doi:10.1167/iovs.02-1192. PMID 15671301. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  10. ^ Richer S (1999). "ARMD—pilot (case series) environmental intervention data". J Am Optom Assoc. 70 (1): 24–36. PMID 10457679. {{cite journal}}: Unknown parameter |month= ignored (help)
  11. ^ a b Richer S, Stiles W, Statkute L; et al. (2004). "Double-masked, placebo-controlled, randomized trial of lutein and antioxidant supplementation in the intervention of atrophic age-related macular degeneration: the Veterans LAST study (Lutein Antioxidant Supplementation Trial)". Optometry. 75 (4): 216–30. PMID 15117055. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  12. ^ Age-Related Eye Disease Study Research Group (2001). "A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8". Arch. Ophthalmol. 119 (10): 1417–36. PMC 1462955. PMID 11594942. {{cite journal}}: Unknown parameter |month= ignored (help)
  13. ^ a b c d SanGiovanni JP, Chew EY, Clemons TE; et al. (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". Arch. Ophthalmol. 125 (9): 1225–32. doi:10.1001/archopht.125.9.1225. PMID 17846363. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  14. ^ "Associations between age-related nuclear cataract and lutein and zeaxanthin in the diet and serum in the Carotenoids in the Age-Related Eye Disease Study, an Ancillary Study of the Women's Health Initiative".
  15. ^ Barker Fm, 2nd (2010). "Dietary supplementation: effects on visual performance and occurrence of AMD and cataracts". Current medical research and opinion. 26 (8): 2011–23. doi:10.1185/03007995.2010.494549. PMID 20590393.{{cite journal}}: CS1 maint: numeric names: authors list (link)
  16. ^ http://onlinelibrary.wiley.com/doi/10.1111/j.1750-3841.2009.01447.x/abstract;jsessionid=350B6E677AC73B3F3FB38975B92835B9.d01t01?systemMessage=Due+to+scheduled+maintenance+access+to+the+Wiley+Online+Library+may+be+disrupted+as+follows:+Monday,+6+September+-+New+York+0400+EDT+to+0500+EDT;+London+0900+BST+to+1000+BST;+Singapore+1600+to+1700
  17. ^ Seddon JM, Ajani UA, Sperduto RD; et al. (1994). "Dietary carotenoids, vitamins A, C, and E, and advanced age-related macular degeneration. Eye Disease Case-Control Study Group". JAMA. 272 (18): 1413–20. doi:10.1001/jama.272.18.1413. PMID 7933422. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  18. ^ Bowen PE, Herbst-Espinosa SM, Hussain EA, Stacewicz-Sapuntzakis M (2002). "Esterification does not impair lutein bioavailability in humans". J Nutr. 132 (12): 3668–73. PMID 12468605.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  19. ^ WHO/FAO Codex Alimentarius General Standard for Food Additives
  20. ^ UK Food Standards Agency: "Current EU approved additives and their E Numbers". Retrieved 2011-10-27.
  21. ^ Australia New Zealand Food Standards Code"Standard 1.2.4 - Labelling of ingredients". Retrieved 2011-10-27.
  22. ^ Reuters, Study finds spinach, eggs ward off cause of blindness
  23. ^ USDA National Nutrient Database for Standard Reference, Release 23 (2010)
  24. ^ Niizu, P.Y. (2005). "Flowers and Leaves of Tropaeolum majus L. as Rich Sources of Lutein". Journal of Food Science. 70 (9): S605–S609. doi:10.1111/j.1365-2621.2005.tb08336.x. ISSN 1750-3841. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  25. ^ FOD025C The Global Market for Carotenoids, BCC Research
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