We can't make this antioxidant pigment ourselves, so eating a diet that is rich in lutein is vital as it is needed for healthy eyes.
These pigments, or carotenoids, are found in high concentrations in the eye, particularly the macula (the small central portion of the retina), and help reduce the risk of light-induced damage to this part of the eye.
Having higher levels of lutein in your diet supports normal vision and may reduce the risk of developing age-related macular degeneration (AMD) – and cataracts. AMD causes loss of sharp central vision needed for reading, driving and recognising faces. It is one of the leading causes of severe vision loss in people over 50.
Dr Sarah Brewer says: ‘Both AMD and cataracts become more common as you get older. Ensuring you have a good intake of lutein can improve vision and decrease the risk of eye disease. Dark green leaves such as kale and spinach are also good sources, but if you don't eat these regularly lutein supplements are available.’
What does lutein do?
Lutein is concentrated in a small area of the retina called the macula, which is responsible for the fine vision needed for focusing on reading, television and seeing objects in detail. Some lutein is also converted into another carotenoid called zeaxanthin, and together they help filter out damaging blue light in the macula.
When we eat foods high in lutein, the antioxidant is transported around the body including to the macula and the lens in the eye.
Lutein has important antioxidant functions – guarding against the effects of free radicals (unstable oxygen molecules) that can damage cells and are implicated in many diseases.
A 2015 study, published in The British Journal of Ophthalmology, investigated the effects of lutein supplements on retinal function and early AMD. It found two groups who took 10mg or 20mg lutein supplements for 48 weeks showed a significant increase in retinal sensitivity, suggesting that lutein could be beneficial for patients with early AMD.
The Age-Related Eye Disease Study (AREDS2) in the US, found those with early signs of macular deterioration who took a supplement containing 10mg of lutein and 2mg of zeaxanthin (along with 500mg vitamin C, 80mg zinc, 2mg copper and 400 iu of vitamin E) daily, for a five-year period, reduced their risk of AMD progressing by 10 to 25 per cent.
Cataracts occur when changes in the lens of the eye cause it to become less clear, resulting in cloudy or misty vision. Research indicates a good lutein intake may make it less likely that cataracts develop. A review of six large studies found people with the higher intakes of lutein and zeaxanthin showed a one to three per cent reduction in their risk of three types of age-related cataracts.
Getting lutein from your diet
Lutein is found in yellow-orange fruits and vegetables including sweetcorn, squash, orange and yellow peppers, carrots, mango and honeydew melon. Leafy green vegetables, especially kale also have a very high lutein content. Egg yolks and sweetcorn are also good sources of both lutein and zeaxanthin.
The Macular Disease Society says the average Western diet is estimated to contain up to 3mg of lutein a day, but studies suggest we need an intake of around 10mg daily. Taking a daily supplement could be a useful top-up.
There are no known side effects of eating a diet rich in lutein, although some people who consume large amounts of carrots or yellow and green citrus fruits can develop a harmless yellowing of the skin called carotenemia.
If you are taking blood-thinning medication including warfarin, talk to your doctor as lutein-rich vegetables such as kale and spinach also contain high levels of vitamin K which may interact with the drug.
There is no UK or EU recommended daily intake, but most recent studies show benefits from taking 10mg of lutein and 2mg of zeaxanthin in supplement form.