Re: Decreased antioxidant levels increase risk of age-related macular degeneration with exposure to sunlight

Doug wrote:

The journal Archives of Ophthalmology recently reported that having
reduced plasma antioxidant levels and increased exposure to sunlight
increases the risk of neovascular, or advanced age-related macular
degeneration (AMD).

In a recent study (titled the European Eye Study), over 4,400
participants over age 65 were analyzed for the presence of macular
degeneration. Their blood plasma was evaluated for vitamins C and E,
the carotenoids lutein and zeaxanthin, and the mineral zinc. Each
individual also completed a questionnaire regarding their typical
exposure to sunlight. This was used to estimate blue light exposure
from visible light, which is known to contribute to the development of
macular degeneration.

Early stage macular degeneration was detected in 2,182 participants,
and 101 had the advanced form of the disease. The research found no
association between blue light exposure and early macular
degeneration.

However, among participants in the lowest quartile (25 percent) of
serum vitamin C, zeaxanthin, vitamin E and zinc, exposure to blue
light significantly increased the risk of advanced macular
degeneration.

Arch Ophthalmol 2008 Oct;126(10):1396-403

http://www.ncbi.nlm.nih.gov/pubmed/18852418

Knowledge is good!

http://tinyurl.com/65nckp

Thanks Doug!

Other things that have been researched in the hope of finding a way
to prevent and/or treat age-related macular degeneration include fatty
fish and fish derived omega-3 PUFAs EPA and DHA, vitamin D,
carbohydrate reduction, and reduction of systemic inflammation. All
these have shown some promise, but more research is needed. Below I
give some examples of existing studies about these.

Unfortunately earlier results with dietary antioxidants such as vitamin
C, vitamin E, zeaxanthin, lutein, and zinc have been somewhat
conflicting. Here some examples:

Tan JS, Wang JJ, Flood V, Rochtchina E, Smith W, Mitchell P.
Dietary antioxidants and the long-term incidence of age-related macular
degeneration: the Blue Mountains Eye Study.
Ophthalmology. 2008 Feb;115(2):334-41. Epub 2007 Jul 30.
PMID: 17664009
doi:10.1016/j.ophtha.2007.03.083
<http://www.ophsource.org/periodicals/ophtha/article/S0161-6420(07)00474-5/abstract>

"Conclusions

In this population-based cohort study, higher dietary lutein and
zeaxanthin intake reduced the risk of long-term incident AMD. This
study confirmed the Age-Related Eye Disease Study finding of
protective influences from zinc against AMD. Higher beta-carotene
intake was associated with an increased risk of AMD."

Age-Related Eye Disease Study Research Group.
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. 2001 Oct;119(10):1417-36.
PMID: 11594942
<http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=11594942>

"Conclusions

Persons older than 55 years should have dilated eye examinations to
determine their risk of developing advanced AMD. Those with
extensive intermediate size drusen, at least 1 large druse,
noncentral geographic atrophy in 1 or both eyes, or advanced AMD or
vision loss due to AMD in 1 eye, and without contraindications such
as smoking, should consider taking a supplement of antioxidants
plus zinc such as that used in this study."

Chong EW, Wong TY, Kreis AJ, Simpson JA, Guymer RH.
Dietary antioxidants and primary prevention of age related macular
degeneration: systematic review and meta-analysis.
BMJ. 2007 Oct 13;335(7623):755. Epub 2007 Oct 8. Review .
PMID: 17923720
doi:10.1136/bmj.39350.500428.47
<http://www.bmj.com/cgi/content/full/335/7623/755>

"Conclusions There is insufficient evidence to support the role of
dietary antioxidants, including the use of dietary antioxidant
supplements, for the primary prevention of early AMD."

Cho E, Hankinson SE, Rosner B, Willett WC, Colditz GA.
Prospective study of lutein/zeaxanthin intake and risk of age-related
macular degeneration.
Am J Clin Nutr. 2008 Jun;87(6):1837-43.
PMID: 18541575
<http://www.ajcn.org/cgi/content/full/87/6/1837>

"Conclusions: These data do not support a protective role of
lutein/zeaxanthin intake on risk of self-reported early AMD. The
suggestion of inverse associations related to the risk of
neovascular AMD needs to be examined further."

Age-Related Eye Disease Study Research Group, SanGiovanni JP, Chew EY,
Clemons TE, Ferris FL 3rd, Gensler G, Lindblad AS, Milton RC,
Seddon JM, Sperduto RD.
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. 2007 Sep;125(9):1225-32.
PMID: 17846363
<http://archopht.ama-assn.org/cgi/content/full/125/9/1225>

"Conclusion Higher dietary intake of lutein/zeaxanthin was
independently associated with decreased likelihood of having
neovascular AMD, geographic atrophy, and large or extensive
intermediate drusen."

O'Connell ED, Nolan JM, Stack J, Greenberg D, Kyle J, Maddock L,
Beatty S.
Diet and risk factors for age-related maculopathy.
Am J Clin Nutr. 2008 Mar;87(3):712-22.
PMID: 18326611
<http://www.ajcn.org/cgi/content/full/87/3/712>

"Conclusions: We showed that several variables related to risk for
ARM are associated with a relative dietary lack of key nutrients.
Our finding that age, the most important and universal risk factor
for ARM, is associated with a relative lack of dietary zeaxanthin,
is an important finding that warrants further investigation."

Charkoudian LD, Gower EW, Solomon SD, Schachat AP, Bressler NM,
Bressler SB.
Vitamin usage patterns in the prevention of advanced age-related
macular degeneration.
Ophthalmology. 2008 Jun;115(6):1032-1038.e4. Epub 2007 Dec 21.
PMID: 18096234
doi:10.1016/j.ophtha.2007.08.003
<http://www.ophsource.org/periodicals/ophtha/article/S0161-6420(07)00856-1/abstract>

"Conclusions

Among patients receiving care for AMD at a tertiary retinal center,
more than one third of those deemed candidates for AREDS-type
supplements were not using them or were using an incorrect dose.
Furthermore, nearly one fifth of participants who were using
high-dose supplements did not have a level of AMD anticipated to
benefit from usage. Increased patient education is needed regarding
the recommendations of AREDS."

This study is commented in the article

Vitamins Help Prevent Vision Loss From AMD -- If Used Correctly
<http://www.sciencedaily.com/releases/2008/06/080602121006.htm>

"... At least eight million Americans are at risk for advanced AMD
which can destroy the central vision needed to recognize faces,
read, drive and enjoy daily life. In 2001 the Age-Related Eye
Disease Study (AREDS) reported findings on its clinical trial that
identified a specific formula of antioxidants (vitamin C, vitamin E
and beta-carotene) and zinc that reduced the probability of
progression to advanced AMD by 25 percent-- either the "wet" or
central geographic atrophy forms---among individuals at risk. ..."

Lutein and zeaxanthin. Monograph.
Altern Med Rev. 2005 Jun;10(2):128-35.
PMID: 15989382
<http://www.thorne.com/altmedrev/.fulltext/10/2/128.pdf>


Here some studies about long-chain omega-3 PUFAs EPA and DHA, and fish:

SanGiovanni JP, Chew EY, Clemons TE, Davis MD, Ferris FL 3rd, Gensler
GR, Kurinij N, Lindblad AS, Milton RC, Seddon JM, Sperduto RD;
Age-Related Eye Disease Study Research Group.
The relationship of dietary lipid intake and age-related macular
degeneration in a case-control study: AREDS Report No. 20.
Arch Ophthalmol. 2007 May;125(5):671-9.
PMID: 17502507
<http://archopht.ama-assn.org/cgi/content/full/125/5/671>

"Conclusion Higher intake of omega-3 LCPUFAs and fish was
associated with decreased likelihood of having NV AMD."

Augood C, Chakravarthy U, Young I, Vioque J, de Jong PT, Bentham G,
Rahu M, Seland J, Soubrane G, Tomazzoli L, Topouzis F, Vingerling JR,
Fletcher AE.
Oily fish consumption, dietary docosahexaenoic acid and eicosapentaenoic
acid intakes, and associations with neovascular age-related macular
degeneration.
Am J Clin Nutr. 2008 Aug;88(2):398-406.
PMID: 18689376
<http://www.ajcn.org/cgi/content/full/88/2/398>

"Conclusions: Eating oily fish at least once per week compared with
less than once per week was associated with a halving of the OR for
NV-AMD."

Chong EW, Kreis AJ, Wong TY, Simpson JA, Guymer RH.
Dietary omega-3 fatty acid and fish intake in the primary prevention
of age-related macular degeneration: a systematic review and
meta-analysis.
Arch Ophthalmol. 2008 Jun;126(6):826-33. Review.
PMID: 18541848
<http://archopht.ama-assn.org/cgi/content/abstract/126/6/826>

"Conclusions Although this meta-analysis suggests that consumption
of fish and foods rich in omega-3 fatty acids may be associated
with a lower risk of AMD, there is insufficient evidence from the
current literature, with few prospective studies and no randomized
clinical trials, to support their routine consumption for AMD
prevention."

Hodge WG, Schachter HM, Barnes D, Pan Y, Low*** EC, Zhang L,
Sampson M, Morrison A, Tran K, Miguelez M, Lewin G.
Efficacy of omega-3 fatty acids in preventing age-related macular
degeneration: a systematic review.
Ophthalmology. 2006 Jul;113(7):1165-72; quiz 1172-3, 1178. Review.
PMID: 16815401
<http://www.ophsource.org/periodicals/ophtha/article/PIIS0161642006003058/abstract>

"Conclusion

There is some clinical evidence for protection of AMD from omega-3
fatty acids. However, the results are not consistent. Hence, our
conclusion is that this issue is neither clearly supported nor
refuted by the present world literature. This is an intriguing
and extremely important question but needs further study first
with prospective cohort designs and, if positive, randomized
clinical trials."

Hodge W, Barnes D, Schachter HM, Pan Y, Low*** EC, Zhang L, Sampson M,
Morrison A, Tran K, Miguelez M, Lewin G.
Effects of omega-3 fatty acids on eye health. Evid Rep Technol Assess
(Summ). 2005 Jul;(117):1-6. Review.
PMID: 16111433
<http://www.ncbi.nlm.nih.gov/books/bv.fcgi?highlight=&rid=hstat1a.chapter.91877>

"Conclusions: Based on the studies identified by this review,
clinical research has only scratched the surface with respect
to understanding the possible utility of the intake of omega-3
fatty acids as a primary or secondary prevention in eye health.
Moreover, seen from the point of view of clinical research's
typical, linear arc—which moves from basic science to
observational research to RCTs, and culminating in the
systematic review/meta-analysis of the observations obtained by
these primary studies—there is a paucity of solid observational
research with which to construct an experimental framework
affording the meaningful conduct of RCTs. For example, there is
little understanding of the exact sources, types and doses of
omega-3 fatty acids, or even the possible duration of their use,
which might usefully serve as definitions of a prevention-
centered “intervention” for any of the eye diseases/visual
impairments examined in our review. Perhaps only with respect
to the question of preventing the development/progression of
advanced ARMD is there some suggestive evidence, which is
underscored by it being a strong public health problem, to
allow researchers to consider conducting an RCT. At the same
time, a single study reporting adverse event data likely does
not permit laying to rest all possible concerns regarding the
short- or long-term safety of omega-3 fatty acid interventions.
It is therefore our view that much more research will need to
be conducted before anything conclusive can be asserted with
respect to the effects of omega-3 fatty acids on eye health. It
is also our understanding that sorting out the possible
benefits of the intake of omega-3 fatty acids in eye health
might profit from taking into consideration the impact of the
concurrent intake of omega-6 fatty acids and, by definition,
the omega-6/omega-3 fatty acid intake ratio."


A study about vitamin D:

Parekh N, Chappell RJ, Millen AE, Albert DM, Mares JA.
Association between vitamin D and age-related macular degeneration in
the Third National Health and Nutrition Examination Survey, 1988
through 1994.
Arch Ophthalmol. 2007 May;125(5):661-9.
PMID: 1750250
<http://archopht.ama-assn.org/cgi/content/full/125/5/661>

"Conclusion This study provides evidence that vitamin D may
protect against AMD. Additional studies are needed to confirm
these findings."


A study about the potential effect of dietary carbohydrates:

Chiu CJ, Milton RC, Klein R, Gensler G, Taylor A.
Dietary carbohydrate and the progression of age-related macular
degeneration: a prospective study from the Age-Related Eye Disease Study.
Am J Clin Nutr. 2007 Oct;86(4):1210-8.
PMID: 17921404
<http://www.ajcn.org/cgi/content/full/86/4/1210>

"Conclusion: Persons at risk of AMD progression, especially those
at high risk of advanced AMD, may benefit from consuming a smaller
amount of refined carbohydrates."


Possible association with CRP and therefore with systemic inflammation:

C-reactive Protein Level and Risk of Aging Macula Disorder. The
Rotterdam Study. Sharmila S. Boekhoorn, MD, PhD; Johannes R.
Vingerling, MD, PhD; Jacqueline C. M. Witteman, PhD; Albert Hofman, MD,
PhD; Paulus T. V. M. de Jong, MD, PhD
Arch Ophthalmol. Vol. 125 No. 10, October 2007, pp. 1396-1401.
<http://archopht.ama-assn.org/cgi/content/full/125/10/1396>

"Conclusion Elevated baseline levels of HsCRP were associated with
the development of early and late AMD in this large population-
based cohort."

--
Matti Narkia

http://ma.gnolia.com/groups/Nutrition
.

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