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===Dexeneración macular===
SeveralVarios studiesestudos indicaron showque thato anincremento increasena inpigmentación maculana pigmentationmácula decreasesdiminúe theo riskrisco forde eyeter diseasesdoenzas suchoculares ascomo age-relateda [[dexeneración macular degeneration]] relacionada coa idade (AMD).<ref name="Richer1999">{{cite journal |author=Richer S |title=ARMD—pilot (case series) environmental intervention data |journal=J Am Optom Assoc |volume=70 |issue=1 |pages=24–36 |date=January 1999 |pmid=10457679 }}</ref><ref name=Richer2004>{{cite journal |author=Richer S, Stiles W, Statkute L, et al. |title=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) |journal=Optometry |volume=75 |issue=4 |pages=216–30 |date=April 2004 |pmid=15117055 }}</ref><ref name="Age2001">{{cite journal |author= |title=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 |journal=Arch. Ophthalmol. |volume=119 |issue=10 |pages=1417–36 |date=October 2001 |pmid=11594942 |pmc=1462955 |author1= Age-Related Eye Disease Study Research Group |doi=10.1001/archopht.119.10.1417}}</ref> TheO onlyúnico randomizedensaio clinicalclínico trialaleatorizado toque demonstratedemostrou aun benefitbeneficio forda luteinluteína inna dexeneración macular degenerationfoi wasun apequeno smallestudo study,no incal whichos theautores authorsconcluíron concludedque thata función visual functionmellora iscoa improvedluteína with(soa luteinou alonexunto orcon luteinoutros togethernutrientes) withe othertamén nutrientsque anderan also that more studynecesarios wasmaiores neededestudos.<ref name=Richer2004/>
Hai probas epidemiolóxicas de que existe unha relación entre as concentracións baixas no [[plasma sanguíneo]] de luteína e zeaxantina, e un incremento do risco de desenvolver [[dexeneración macular relacionada coa idade]] (AMD).
There is [[epidemiology|epidemiological]] evidence of a relationship between low [[blood plasma|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.<ref name="PMID17846363" />
En 2013, informouse en JAMA dos resultados do Estudo 2 de enfermidades oculares relacionadas coa idade (AREDS2). O estudo AREDS2 foi un estudo que duron cinco anos deseñado para comprobar se a formulación [[AREDS]] orixinal que se vira que reducía a progresión de dexeneración macular relacionada coa idade nun 25% podería ser mellorada engadindo algúns dos seguintes compoñentes: ácidos graxos [[omega-3]]; luteína e zeaxantina; retirando o [[beta-caroteno]]; ou reducindo o [[cinc]].<ref name="AREDS2">http://www.nei.nih.gov/news/pressreleases/050513.asp</ref> No AREDS2, os participantes tomaron unha destas catro formulacións AREDS: a formulación AREDS orixinal, a formulación sen beta-caroteno, o AREDS baixo en cinc, e o AREDS sen beta-caroteno e baixo en cinc.<ref name="AREDS2" /> Ademais, tomaban unha de catro suplementacións ou combinacións adicionais, entre as que estaban a luteína e zeaxantina (10 mg e 2 mg), ácidos graxos omega-3, luteína/zeaxantina e ácidos graxos omega-3, ou placebo.<ref name="AREDS2" /> O resultado foi que non se observaba un beneficio adicional global ao engadir ácidos graxos omega-3 ou luteína e zeaxantina á formulación.<ref name="AREDS2" /> Porén, o estudo atopou beneficios en dous subgrupos de participantes: os que non tomaron beta-caroteno, e os que tiñan pouca luteína e zeaxantina na súa dieta.<ref name="AREDS2" /> A eliminación do beta-caroteno non freaba os efectos protectores da formulación contra o desenvolvemento de dexeneración macular avanzada relacionada coa idade en estado avanzado, o cal era importante porqeu as altas doses de beta-caroteno foran ligadas cun alto risco de padecer cancro de pulmón en fumadores.<ref name="AREDS2" /> Recomendouse substituír o beta-caroteno por luteína e zeaxantina en futuras formulacións.<ref name="AREDS2" />
In 2007, in a six-year study, John Paul SanGiovanni of the [[National Eye Institute]], [[Maryland]] found that lutein and zeaxanthin ([[nutrients]] in [[Egg (food)|eggs]], [[spinach]] and other green vegetables) protect against [[blindness]] ([[macular degeneration]]), affecting 1.2 million [[United States|Americans]], mostly after age 65. Lutein and zeaxanthin reduce the risk of AMD.<ref name="PMID17846363"/>
In 2013, findings of the Age-related Eye Disease Study 2 were reported in JAMA; AREDS2 was a five-year study designed to test whether the original [[AREDS]] formulation that was shown to reduce progression of age-related macular degeneration by 25 percent would be improved by adding omega-3 fatty acids; adding lutein and zeaxanthin; removing beta-carotene; or reducing zinc.<ref name="AREDS2">http://www.nei.nih.gov/news/pressreleases/050513.asp</ref> In AREDS2, participants took one of four AREDS formulations: the original AREDS formulation, AREDS formulation with no beta-carotene, AREDS with low zinc, AREDS with no beta-carotene and low zinc.<ref name="AREDS2" /> In addition, they took one of four additional supplement or combinations including lutein and zeaxanthin (10 mg and 2 mg), omega-3 fatty acids (1,000 mg), lutein/zeaxanthin and omega-3 fatty acids, or placebo.<ref name="AREDS2" /> The study reported that there was no overall additional benefit from adding omega-3 fatty acids or lutein and zeaxanthin to the formulation.<ref name="AREDS2" /> However, the study did find benefits in two subgroups of participants: those not given beta-carotene, and those who had very little lutein and zeaxanthin in their diets.<ref name="AREDS2" /> Removing beta-carotene did not curb the formulation's protective effect against developing advanced AMD, which was important given that high doses of beta-carotene had been linked to higher risk of lung cancers in smokers.<ref name="AREDS2" /> It was recommended to replace beta-carotene with lutein and zeaxanthin in future formulations for these reasons.<ref name="AREDS2" />
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