Lutein (pronounced loo-teen) and Zeaxanthin (pronounced zee-uh-zan'-thin) are two major carotenoids and are both antioxidants. Cartenoids are plant pigments responsible for bright red, yellow and orange hues in many fruits and vegetables. The most common ones in the Western diet, and the most studied, are alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein, zeaxanthin and lycopene.
In nature, lutein and zeaxanthin appear to absorb excess light energy to prevent damage to plants from too much sunlight, especially from high-energy light rays called blue light.
Lutein and zeaxanthin are associated primarily with eye health, in fact, thanks to scientific studies, notably the Age Related Eye Disease Study (AREDS) by the National Eye Institute, lutein and zeaxanthin have joined the ranks of beta-carotene and zinc as proven nutritional support for combating the natural effects of aging when it comes to vision and eye health.
Lutein is known as a carotenoid vitamin that acts as a colour pigment in the macula and retina of the eye. If you think of vitamin D as the 'sunshine vitamin' then you can think of lutein as the 'vision vitamin'.
Research has shown that lutein acts as a natural light filter for the eye, protecting it from potential damage caused by ultraviolet light, digital blue light emitted from computer screens and mobile devices and even a poor diet. In fact, various studies have shown that a direct relationship exists between lutein intake and pigmentation in the eye.
Zeaxanthin is the dominant component within the very centre of the macula. It is the other main carotenoid, along with lutein, that provides pigmentation in the eyes. These two antioxidants are highly concentrated in the eyes compared to the rest of the body. Zeaxanthin is dominant in the centre of the macula, whereas lutein is dominant in the surrounding retina.
Lutein and Zeaxanthin are stronger together
Both lutein and zeaxanthin act as filters for your eyes, blocking out harmful UV rays and other high-energy wavelengths. As antioxidants, these important pigments guard the body from damaging effects of free radicals, which are unstable molecules that can destroy cells and play a role in many diseases.
Oxidation leads to the formation of free radicals, cloudy lenses and retinal damage. It is believed that lutein and zeaxanthin in the macula block blue light from reaching the underlying structures in the retina, thereby reducing the risk of light-induced oxidative damage that could lead to macular degeneration (AMD).
In fact research has shown that the more lutein and zeaxanthin there is the eye, the less likely you are to suffer from age related vision loss including AMD and if you already have it, it may slow down the progression of the disease.
- A study published in Nutrition & Metabolism found that a nutritional supplement containing meso-zeaxanthin, lutein and zeaxanthin effectively increased the optical density of the macular pigment in eyes of the majority of human subjects. The macular pigment is believed to offer protection against the development of macular degeneration.
- Studies published in American Journal of Epidemiology, Ophthalmology and Archives of Ophthalmology found higher levels of lutein and zeaxanthin in the diet are associated with a lower incidence of AMD.
- Two studies published in Investigative Ophthalmology and Visual Science found that eyes with greater levels of macular pigments were less likely to have or develop macular degeneration.
- In a study published in the Journal Optometry, participants with early AMD who consumed 8 mg per day of dietary zeaxanthin for one year improved their night driving and their visual acuity.
- In addition to protecting the retina, lutein and zeaxanthin also may reduce the risk of cataracts. Recent studies published in Archives of Ophthalmology have found that healthy diets with high levels of lutein, zeaxanthin and other carotenoids were associated with a lower risk and prevalence of cataracts in women.
AREDS2 was a follow-up to the original 5 year AREDS study mentioned above, which found the use of a daily antioxidant supplement containing beta-carotene, vitamin C, vitamin E, zinc and copper reduced the risk of progressive AMD by 25% among participants with early and intermediate macular degeneration.
The aim of AREDS2 was to assess the effect of other nutrients, including lutein and zeaxanthin, on the prevention of AMD and other age-related eye diseases.
The results of the study showed that participants with early signs of macular degeneration who took a modification of the original AREDS nutritional supplement containing 10 mg lutein and 2 mg zeaxanthin (and no beta-carotene) every day over the course of the 5 year study period had a 10-25% reduced risk of AMD progression.
Those participants whose diets contained the lowest amounts of foods containing natural lutein and zeaxanthin experienced the greatest AMD risk reduction from taking the daily nutritional supplement.
While AREDS2 and other studies provide evidence that lutein and zeaxanthin may play a key role in either preventing AMD or reducing the risk of progression of the disease, it's less clear if these carotenoids help prevent cataracts. In AREDS2 supplemental lutein and zeaxanthin had no effect on cataract risk or progression.
Sources of Lutein and Zeaxanthin
Lutein and zeaxanthin are not made within the body and can only be obtained from what we eat therefore a proper diet and/or supplementation is essential - however the good news is these two antioxidants are found in abundance together in many fruits and vegetables.
Good sources of lutein and zeaxanthin include brightly coloured fruits and vegetables such as carrots, squash, pumpkin, paprika, yellow-fleshed fruits, oranges and melon as well as leafy green vegetables such as kale, spinach, cos lettuce, collard greens, Brussels sprouts and broccoli.
Taking vitamin supplements does not replace a healthy diet however it can improve it as it can be hard to achieve the high doses of some vitamins and minerals required from food alone. It's also important to remember that eating a diet high in fruits and vegetables also gives extra benefits to health.
There currently is no Recommended Dietary Allowance (RDA) or Recommended Daily Intake (RDI) for lutein or zeaxanthin, but some nutritionists recommend at least 6 mg of lutein per day for eye health.
There are no known side effects of taking too much lutein or zeaxanthin. If too many foods or supplements containing carotenoids are taken, the skin can develop a harmless yellow colour but this is very rare and will disappear on reducing the amount taken or eaten.