So how can you help to optimise eye health both now and into the future?
Despite these alarming statistics, deterioration of the eyes is not, in fact, an inevitable consequence of ageing; oxidative stress, smoking, obesity and sub-optimal nutritional status are modifiable factors that have all been implicated in problems associated with eye health. Fortunately, there are effective nutritional steps that can be taken to support optimal eye health. Just like any other part of the body, the eyes rely on a constant source of good nutrition to function optimally. Scientific studies have now shown that a healthy diet and supplementation with a specific combination of synergistic nutrients can indeed help to maximise eye health and prevent the progression of eye diseases, both now and into the future.1
The AREDS Study
In 2001, a ground-breaking study, now referred to as the AREDS (Age Related Eye Disease Study) found that taking high levels of specific nutrients, in particular zinc and antioxidants, can reduce the risk of developing age-related macular degeneration (AMD) by about 25%.2
This major, large-scale clinical trial followed about 3,600 study participants with varying stages of AMD. The results showed that this combination of nutrients, while not a cure for AMD, may play a key role in helping people at high risk for developing AMD keep their remaining vision.
The key features of this trial were the specific combination of nutrients used in the study and the fact that higher levels of vitamins and minerals than would normally be found in a healthy diet, were used. The second phase of this study, AREDS 2, is now underway, which promises to offer even more scientific data to support the use of nutrients to support optimum eye health.3
The role of antioxidants in eye health
Antioxidant nutrients are, arguably the most important nutrients for eye health.
Experts agree that cellular damage due to oxidation is believed to be a major
contributing factor to the development of a wide spectrum of eye diseases. In
particular, the retina is highly susceptible to oxidative damage due to its high
oxygen
consumption, the fact that it contains high levels of unsaturated fatty acids, and
its
exposure to light.
Multivitamins for cataract prevention
Cataracts are the result of clouding of the eye lens. Evidence suggests that long-term
use of multivitamins may help to delay the development of cataracts.
Focus on key nutrients for optimum eye health:
Vitamins C & E
Key antioxidant vitamins C & E, help to neutralise potentially damaging free radicals and so may help to protect eye health. Fat-soluble vitamin E has been shown to be more protective than fat-soluble vitamin A. Strengthening of the eye defences by increasing intake of these vitamins may be helpful in preventing chronic ageing eye diseases. Recent well-designed and controlled studies support this, including in particular, the AREDS study.
Alpha Lipoic Acid
An essential addition to any nutritional strategy for supporting optimal eye health,
alpha lipoic acid is a vitamin-like substance which plays a unique and key role
as a
potent antioxidant in protecting against both fat and water soluble free radicals
and
enhancing the effects of other antioxidants.
Zinc
The specific nutrient combination in the AREDS study contained a high amount of zinc. Experts agree that zinc is a highly important nutrient to support eye health. In particular, the retina contains a high amount of zinc, indicating just how essential this mineral is for optimum eye function:
- Zinc works in synergy with taurine in the photoreceptors of the eye
- Zinc is essential for the function of an important enzyme in the eyes, retinal dehydrogenase
- Zinc helps to stabilise rhodopsin, a protein activated by light, or modulate light initiated reactions
- Zinc is a powerful antioxidant and helps to protect the eye from damaging free
radicals
Copper synergy with Zinc
An essential mineral for eye health, copper was added to the AREDS formulations
containing zinc to prevent copper deficiency anaemia, a condition associated with
high levels of zinc intake.
Copper binds with zinc so it is always prudent to supplement copper alongside zinc.
Copper also works with vitamin C to fight oxidative stress, and is essential for
proper
enzyme functioning.
Bilberry
Bilberry, similar to blueberry has a long history of use for the treatment of eye conditions and has potent antioxidant activity due to its active constituents, flavonoid anthocyanosides. Bilberry is an important addition to any eye health improvement programme and has been shown to help reduce macular inflammation.
Taurine
Taurine is the most abundant amino acid in the eyes, low levels of which are
associated with degeneration of the retina and formation of cataracts. Studies support
the role of this important amino acid during regeneration of the optic nerve.8 Experts
agree that taurine is an essential part of any treatment strategy to support optimal
eye
health.4
Lutein & Zeaxanthin
The macular region of the eye is composed of the carotenoids, lutein and zeaxanthin; carotenoids are powerful free radical scavengers, their role in eye health then is protective.
Lutein and Zeaxanthin have been shown to:
- Protect the eyes against photodamage by filtering out potentially damaging blue light5
- Provide antioxidant protection against peroxidation of fatty acids in the photoreceptor membrane5
- Protect the blood vessels that supply the macular region5
Epidemiological evidence strongly suggests that higher amounts of macular pigment reduces the risk of developing AMD; supplementation with these important carotenoids is therefore strongly recommended to support optimal eye health. Studies have shown that higher carotenoid intakes are associated with reduced risks of developing AMD.6,7 Lutein and zeaxanthin are currently being further studied for their unique roles in eye health in the AREDS 2 study.3
A word on beta-carotene…..
Another member of the carotenoid family,
beta-carotene was included in the nutrient
combination in the original AREDS study, yet has been excluded from the follow-on
study AREDS 2 because it has been linked to an increased risk of lung cancer in
smokers.8 Unlike lutein and zeaxanthin, beta-carotene is not present in the human
retina. Experts agree that lutein and zeaxanthin are the preferred source of
carotenoids for eye protection since they have been consistently linked with a reduced
risk of cataract and AMD and appear to be intrinsically protective of the retina,
with
no reported adverse side effects.
References:
1) Clinical Review: Age related macular degeneration. BMJ 2003: 326:485-488 (1 March). Amresh Chopdar, Usha Chakravarty, Dinesh Verma. East Surrey Hospital, Redhill, Surrey. Queen’s University and Royal Victoria Hospital, Belfast. Doheny Retina Institute, Keck School of Medicine, University of Southern California, Los Angeles
2) A randomised, 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 (Age Related Eye Disease Study Group). Arch Opthalmol. 2001 Oct: 119 (10): 1417-3 www.nei.nih.gov/amd http://www.nei.nih.gov/amd/summary.asd
3) Emily Y Chew, M.D. John Paul SanGiovanni, Sc.D. AREDS2 – Age-Related Eye Disease Study 2 (AREDS2): A Multi-Centre, Randomised Trial of Lutein, Zeaxanthin and Omega-3 long Chain Polyunsaturated Fatty Acids (Docosahexaenoic Acid (DHA) and Eicosapentaenoic Acid (EPA)) in Age-Related Macular Degeneration.
4) Neurochem Res 1999 Nov; 24 (11): 1333-8. Taurine and its trophic effects in the retina. Lima L
5) NIH Eye Disease Case-Control Study (Seddon JM et al. JAMA. 1994; 272:1413-1420)
6) Dietary Carotenoids, vitamins A, C and E, and advanced age-related macular degeneration. Seddon JM, Ajani UA, Sperdoto et al. JAMA 1994: 272: 1413-20
7) Associations between intermediate age-related macular degeneration and lutein and zeaxanthin in the Carotenoids in Age-related Eye Disease Study (CAREDS): ancillary study of the Women’s Health Initiative. Moeller SM, Parekh N, Tinker I, Ritenbaugh C et al. Arch Opthalmol. 2006 Aug: 124 (8): 1151-62
8) Vitamin supplement use and incident cataracts in a population-based study. Mares-Periman JA, Lyle BJ, Klein R, Fisher AI et al. Arch Opthalmol 2000 Nov; 118 (11): 1556-63
