EYES NEED GOOD NUTRUTION
There is an increasing body of research to show that some vitamins, minerals and other nutrients may be beneficial to long term eye health.
A paper presented to the Association for Research in Vision and Ophthalmology in April 2002 demonstrated that a low dietary intake of antioxidants and nutrients might increase the risk of developing central retinal damage known as age related macular degeneration.
A study by the National Institute of Health found that a diet rich in carotenoids, substances which the body cannot produce, resulted in a 43% lower risk of developing age related macular degeneration. Carotenoids include alpha-tocopherol, beta-carotene, lutein and zeaxanthin.
Studies for the Association for Research in Vision and Ophthalmology found that a combination of antioxidants and zinc showed a 25% reduction in the progression to advanced age related macular degeneration.
It is stated that there is about a 50% prevalence of malnutrition amongst the elderly who may have difficulty chewing and suffer from loss of appetite. An inadequate diet may have severe consequences for vision.
ANTIOXIDANTS AND CAROTENOIDS
Macular pigment at the centre of the back of the eye or foveola is essential to good vision and is greater in men than in women. The loss of this macula pigment, which filters out blue light, results in a reduction of contrast sensitivity. A daily intake of foods rich in antioxidants and carotenoids can increase levels of pigment density and improve central vision. Smoking tobacco has been shown to reduce pigment density.
Carotenoids are mainly concentrated in the central portion (macular) of the retina to protect the eye against blue light. Carotenoids can protect the eye against age-related macular degeneration and are to be found in corn, melon and spinach. Female long-sighted hypermetropic elderly patients are more at risk than anyone else, possibly due to reduction in oestrogen levels after the menopause.
OMEGA 3 FATTY ACIDS
Omega 3 fatty acids are essential dietary components for normal retinal function but cannot be synthsised by the body. Omega 3 is found in abundance in oily fish or can be taken as supplements. Due to a build up of toxins from tuna, swordfish and marlin, a maximum of four portions of these oily fish a day is recommended. Omega 3 can reduce blood pressure and cause blood thinning so patients on cardiovascular drugs or warfarin should consult their GP before taking omega 3 supplements.
Humans are about the only animals unable to produce vitamin C and therefore require it a spart of the diet. Women can reduce their risk of early-onset cataract by taking Vitamin C according to researchers from Tufts University, Boston in the USA. The risk of developing cortical cataracts was 60% less when vitamin C is taken for 10 years.
LUTEIN and ZEAXANTHIN
Lutein and zeaxanthin are carotenoid antioxidants which increase the pigment density of the fovea which is the vital central portion of the eye and can protect against dangerous blue light. They are are the only carotenoids found in the crystalline lens and macula of the human eye. Good sources of lutein are dark green leafy vegetables such as Brussels sprouts, spinach, broccoli, cabbage and lettuce. Zeaxanthin is present in naturally occurring yellow/orange foods except citrous fruits, pumpkin and carrots.
Eggs and spinach may significantly reduce the risk of cataracts by 20% and age-related macular degeneration by 40% according to the Journal of the American College of Nutrition because they contain high levels of lutein and zeaxanthin.
Smoking reduces the amount of lutein and zeaxanthin in the central retina (fovea) as well as reducing antioxidants and being antagonistic to zinc.
Visual function is improved when macular density is increased with lutein according to Dr Stuart Richer of Chicago who announced the findings of the lutein antioxidant supplementation trial in April 2004 and published in "Optometry".
Cinnamon may be able to help regulate blood sugar levels according to Reuters Health Dr Richard Anderson at the Human Nutrition Research Centre. A teaspoonful per day is the recommended amount for non-insulin dependent diabetes to prevent the need for drugs.
Blueberries are known to be rich in anti-oxidants but research carried out by the United States Department of Agriculture in 2004 found that a substance called pterostilbene (which activates rat liver cells' PPAR-alpha receptors) can also help to reduce cholesterol and therefore reduce the possibility of patients acquiring ARMD (age-related macular degeneration). Pterostilbene is said to be similar to the substance resveratrol found in grapes and red wine.
NUTRITION AND CATARACT
A recent study (REACT) showed that a combination of vitamins A, C and E had a minor effect in reducing the rate of progression of cataract.
General Nutrition Centre
It is known that the anti-oxidant vitamins A, C and E are significant in maintaining retinal function and some studies have shown that they may have a protective role against the development of age-related macular degeneration (ARMD) and cataract. The government recommend eating five portions of fruit and vegetables each day an amount achieved by 13% of men and 15% of women. There is a safe dose limit for each vitamin which should not be exceeded. Beta-carotene is an anti-oxidant related to Vitamin A and is resposible for giving some fruit and vegetables their yellow and red colours but if consumed in excess can damage the liver and unborn foetuses.
In socio-economically deprived areas where poor nutrition is evident there is a greater chance of developing these two eye conditions.
The anti-oxidant vitamins are A, C and E, and are present in peppers, mango, peaches, carrots, green leaf foods such as spinach , kale and broccoli, fruits, nuts and root vegetables.
Vitamin A is present in dairy products (such as butter), green plants and in yellow and orange fruits. Carrots are the root vegetable with proportionally most vitamin A. Fruits have some vitamin A, but leaves have more.
is to be found in citrus fruits and blackcurrants.
is a fat-soluble anti-oxidant which helps to maintain cell membrane integrity in the body, including the retina, and is present in soya, corn and olive oils, cereals, nuts and oily fish.
There are about 20 minerals which are essential to general health but zinc and
are thought to be particularly beneficial to the eye. Selenium is said to help prevent breast cancer and levels of selenium in the soil in Europe is declining. Zinc is present in drinking water, meat, eggs, whole cereals and pulses while selenium can be found in meats, cereals and dairy products. Increased zinc can inhibit copper uptake so many zinc supplements contain copper to compensate.
DAILY AMOUNTS SUGGESTED AS BEING THE MOST APPROPRIATE FOR EACH VITAMIN AND MINERAL.
1 mg (milligram)
Various products are listed below which may help the visually impaired but one should to limit the risk factors which may cause poor vision. It helps to get plenty of exercise and nutritious foods but to avoid smoking, excess alcohol and ultra-violet light.
PRESERVISION ORIGINAL SOFT GELS
Ocuvite PreserVision was the antioxidant vitamin supplement formulation used in the AREDS study, a 10 year independent research programme conducted by the National Eye Institute of America. PreserVision Original is available in soft gel form, and contains high levels of beta-carotene, vitamin C, vitamin E, and zinc in proportions specially prepared for the eyes. It is available in packs of 60 tablets and it is recommended to take 2 tablets twice per day.
PRESERVISION LUTEIN SOFT GELS
Preservision Lutein is similar to Preservision Original but beta-carotene is replaced with lutein and is recommended for those patients who should avoid beta-carotene such as smokers or ex-smokers.
ICAPS include more vitamins and minerals than Ocuvite Lutein plus zeaxanthin for retinal and crystalline lens health. There are 60 tablets per pack with a recommended dosage of 2 tablets per day. Two Icaps are equal to the equivalent of 4 servings of fruit and vegetables per day.
Products such as Visiomax and Selenium-ACE are available from health food shops. Bilberry extract is high in antioxidants and when combined with lutein is said to be very beneficial to the health of the retina.