The macula, a specialized part of the retina responsible for central vision, is protected by a kind of natural sunscreen to prevent the sensitive vision cells from being damaged by the energy from blue or UV light. This natural sunscreen is made up of a yellowish ‘macular pigment’ – a mixture of three light-absorbing compounds; lutein, zeaxanthin and meso-zeaxanthin.
Our bodies cannot make these three compounds, which are made by plants to absorb light in order to carry out photosynthesis, so we have to eat them. Lutein and zeaxanthin are found commonly in dark green leafy veg such as kale and spinach, and also bell peppers, corn and saffron. Meso-zeaxanthin is generally not found in plants – it is thought to be made in our bodies from lutein (although it is also present in some fish, especially in their skins, so we may be able to get some from our diet too). These pigments, once we eat them, appear to be important in our vision and in helping keep the macula healthy.
Experiment 1 saw Michael Mosley taking supplements containing the three macular pigments every day for 12 weeks. His blood levels of the chemicals, the amount of macular pigments in his eyes, and his eyesight were thoroughly tested before and after taking the pills. Overall, there was an improvement in many aspects of his vision – but especially his perception of yellow/blue colours and his night vision), and increase in his macular pigment density and an increase in these compounds in his blood.
Experiment 2 tried increasing intake through diet. Drinking a specially designed green smoothie daily nearly doubled the volunteers' lutein levels in their blood but zeaxanthin levels did not increase, and there was no change in the levels of macular pigments or improvements in their eyesight, perhaps because these pigments take a while to get in to different tissues in the body, including the eye, so taking these foods for longer could show more of an effect. It may also be that the recipe needs tweaking.
Green smoothie recipe. Add 125g cooked kale, 1 tbsp almond butter, ½ tsp wheat germ oil, and a small amount of 80ml milk ( 2% with DHA) to a food processor or high-powered blender; blend until a smooth paste forms. Add remaining ingredients: ½ small (6”) banana, 125g kiwi (cut in pieces), 125g pineapple chunks canned in water, ½ medium apple (peeled), ¼ cup fresh mint leaves (for flavouring), ½ lime (squeezed ) and the remaining milk and continue to blend until smooth.
Good food sources. Kale and other leafy greens, kiwi fruit, bell (sweet) peppers, saffron, sweetcorn, saffron. Also egg yolks - with milk and wheatgerm oil to help absorption. [This paragraph is probably from the Lifespan magazine.]
Conclusion: The
strongest evidence at the moment is for supplements containing all
three of the macular compounds, though many researchers believe that
simply eating a diet rich in leafy green vegetables should be enough to
keep your levels healthy. (Be aware, though, that carrots do NOT contain
particularly high levels of any of these compounds.)
Can I Improve my Eyesight on Trust Me, I'm a Doctor, BBC2
