By Ian Marber
PUBLISHED: 15:55 EST, 21 April 2012 | UPDATED: 15:55 EST, 21 April 2012
Actress Dame Judi Dench is among the half-a-million adults in the UK sufferering from age-related macular degeneration (AMD). It afflicts 10 per cent of those aged over 66 and almost a third of those over 75.
When the macula, a spot located in the centre of the retina, deteriorates, the most central field of sight is affected. This makes reading, driving, writing and recognising the faces of people close by difficult.
Treatments include drugs, radiation and laser therapy, all of which have varying degrees of success. But a combination of nutrients found in everyday foods has been found to reduce the symptoms of macular degeneration by 19 per cent, and cut the risk of developing the condition by up to a quarter.
The macula is yellow and this is attributed to the presence of lutein and zeaxanthin in its pigment. These nutrients, known as carotenoids, play an important role in protecting vulnerable tissue, including those found in the eyes. Vitamin E, Vitamin C, zinc and Omega 3 fats are also key.
But how much food has to be eaten to achieve the doses of the most effective nutrients? In some cases, diet alone is sufficient, but we should also consider taking supplements.
LUTEIN – SUPPLEMENT
FOUND IN: Kale, spinach, peas, corn
Just 6mg of lutein a day could reduce the risk of AMD by more than 40 per cent, according to a 1994 study at Harvard University. However, the American Macular Degeneration Foundation suggests that up to 30mg daily is beneficial.
To get 10mg one would have to eat 2oz (66g) cooked kale, 5oz (150g) cooked spinach or 4oz (100g) raw spinach. Alternatively, you would need to eat 1.1lbs (500g) of peas, and 1.5lbs (700g) of corn to get that amount, which is why I would recommend a supplement.
ZEAXANTHIN – SUPPLEMENT
FOUND IN: Oranges, goji berries, spinach, collard greens
This is the pigment that gives paprika, corn and saffron their characteristic colour. The chemical also forms part of the structure of the macula. The vital role of zeaxanthin in AMD was highlighted by the University of Southampton in 2003.
While no data exists to establish a recommended dose, a major clinical trial in the United States – known as the Age-Related Eye Disease Study (AREDS) – is working with 2mg in supplement form. Concentrated zeaxanthin is a potent nutrient. To derive 2mg we would have to eat 2.2lbs of cooked spinach or 27 oranges.
OMEGA 3 – DIET
FOUND IN: Oily fish, nuts and seeds
The quality of the macula is improved by Omega 3, according to a French study in 2011. However, the ratio between Omega 3 and Omega 6 fats is also important. A typical Western diet favours Omega 6 (found in vegetable oils, many meats and most nuts) over Omega 3 by a ratio of 10:1, yet last year researchers recommended a ratio of 5:1.
In day-to-day terms, this means favouring Omega 3 fats to get the 1,000mg as used in the AREDS study. You get this from half a portion of canned salmon or fresh trout, two-thirds of a tin of tuna, a handful of walnuts, or 10 tablespoons of olive oil.
A teaspoon of linseed oil will also give you all you need.
ZINC – SUPPLEMENT AND DIET
FOUND IN: Seafood, poultry and meat, nuts, seeds and beans
The recommended daily intake for zinc is 15mg but to combat AMD, a study in March found 80mg of zinc in supplement form to be most effective.
Oysters are also a rich source – just four of them will give you the recommended dose, as would a portion of lean roast beef (5oz). But you would have to eat four chicken breasts or a whole bag of peanuts (8oz), which would also contain more than 3.5oz of fat and 1,400 calories, to achieve this kind of zinc intake. So a supplement is probably a good back-up.
VITAMIN C – DIET
FOUND IN: All fruits and vegetables
Getting Vitamin C from food allows the nutrient to be absorbed in a more regulated way. A combination of Vitamin C-rich foods throughout the day should easily get you to 500mg, which has been found to improve macula density by 19 per cent.
Oranges aren’t the only fruit when it comes to Vitamin C. Try to include a variety of foods in your diet – blueberries or any other dark berries, broccoli and carrots are all good sources.
Raw is best, otherwise steam or sautee rather than boil, which washes out some of the Vitamin C content.
VITAMIN E – SUPPLEMENT
FOUND IN: Nuts, seeds and oils
Vitamin E is found naturally alongside essential fats and additional Vitamin E may not be required. The AREDS suggestion is 400iu (the measurement used to quantify vitamin intake), although the recommended daily intake is just 22iu.
You would have to munch your way through 3.3lb (1.5kg) of almonds, or 63 avocados to get this amount, so a supplement is the best bet. A word of caution: Vitamin E can also thin the blood and should not be taken while on blood-thinning medication such as Warfarin, so check with your GP.