Lutein & Zeaxanthin
What are Lutein and Zeaxanthin?
Lutein belongs to a family of nutrients called carotenoids. Carotenoids are pigments that color our foods with yellows, reds and oranges. These pigments are often called phyto- (plant) nutrients and are found in plants and plant foods like fruits and vegetables.
A nutrient that is often found with lutein is zeaxanthin. Although often thought of as lutein’s little sister, since it is chemically similar, zeaxanthin is so much more, having a unique function all its own. Zeaxanthin is most often found in the same foods as lutein and it works with lutein in the body.
How important to our health are lutein and zeaxanthin? Consider a few facts:
- Of the more than 600 carotenoids found in nature, lutein and zeaxanthin are the only ones found in the eye
- Lutein is also the major carotenoid found in breast milk
- Lutein and zeaxanthin represent 75 percent of the carotenoids in our brains
Lutein and Zeaxanthin in the Diet
Lutein and zeaxanthin cannot be made by our bodies like many other nutrients can. Luckily we can get them by enjoying a broad range of fruits and vegetables or through supplements.
Since lutein and zeaxanthin are yellow pigments, you might think they are only found in yellow foods like corn, egg yolks and yellow squash. While those are all good sources, they are even more prevalent in dark leafy greens like kale, spinach and collard greens—their color hidden by the green pigment – chlorophyll – in those plants. Other excellent sources of lutein and zeaxanthin are kiwi fruit, grapes and zucchini.1
Given how reluctant many people are to eat their green vegetables, it’s not surprising that intake of lutein and RR-zeaxanthin is low: men and women less than 50 years of age consume, on average, less than 2 mg/day. Researchers, however, are using 10 mg of lutein and 2mg of zeaxanthin per day to determine their effects on healthy vision.
Putting Life in Focus with Lutein and Zeaxanthin
Lutein and zeaxanthin have several functions in the human body. Of the 40 to 50 carotenoids in our diet, they are the only two found in the eye.
First, lutein and zeaxanthin are potent antioxidants, which helps them protect our bodies against a process called oxidation. One of the most commonly cited examples of oxidation is rusted metal – something we certainly don’t want to see happen inside our bodies. Oxidation can happen in the eye from the environment like light from the sun. In fact, just being alive causes oxidation - it is a natural part of aging.
Lutein and zeaxanthin also play a direct role in vision. They are highly concentrated in a small area in the center of the retina called the macula. The macula is responsible for our central vision and the sharpness with which we see things (known as visual acuity). Because the macula is yellow, lutein and zeaxanthin are often referred to as macular pigment.
Macular pigment enhances healthy vision by filtering light and enhancing detail and contrast. Studies suggest that macular pigment may benefit activities such as driving at night and protect against harmful effects that might occur after staring at a computer for too long.23 Macular pigment density has also been shown to increase the speed with which we process images and to help us see in dim light.456 Lutein and zeaxanthin may also help the nerves to the eye talk to one another — a process known as neuronal signaling.789
These effects happen throughout our lives: as infants, while our vision is developing; as we mature during childhood; and as our eyes become more vulnerable with age.10
Lutein and zeaxanthin are also found elsewhere in the eye: in the iris, the lens and photoreceptors.12
1 Sommerburg, et al. Br J Ophthalmol 1998;82:907–910
2 Yagi A, Fujimoto K, Michihiro K, Goh B, Tsi D, Nagai H. Appl Ergon. 2009 Nov;40(6):1047–54.
3 Hammond BR Jr., Ophthalmic Physiol Opt 2005;25:315–9.
4 Renzi LM, Hammond BR Jr. Ophthalmic Physiol Opt 2010;30:351–7.
5 Renzi LM, Hammond BR. Exp Eye Res 2010;91:896–900.
6 Stringham JM, Hammond BR Jr. Optom Vis Sci Off Publ Am Acad Optom. 2007 Sep;84(9):859–64.
7 Stringham JM, Hammond BR. Optom Vis Sci Off Publ Am Acad Optom. 2008 Feb;85(2):82–8.
8 Stringham JM, Hammond BR Jr. Dietary lutein and zeaxanthin: possible effects on visual function. Nutr Rev. 2005 Feb;63(2):59–64.
9 Hammond BR Jr. Nutr Rev. 2008 Dec;66(12):695–702.
10 Hammond, Nutr. Rev. Vol. 66(12):695–702.