Lutein

Lutein is a yellow chemical found in many plants. It belongs to a group of compounds called carotenoids, which give fruits and vegetables their bright colors. Plants make lutein to help them use sunlight for growth and to protect themselves from too much light.

Animals, including humans, get lutein by eating plants. It is especially found in green leafy vegetables like spinach and kale, as well as in yellow carrots. In our eyes, lutein collects in a small spot called the macula lutea, where it may help our vision, though scientists are still learning exactly how it works.

Lutein is similar to another compound called zeaxanthin, and the two can change into one another in our bodies. Because it does not mix with water, lutein is found in fatty parts of foods, like egg yolks. Its special structure lets it absorb light, which is why it gives plants their yellow color.

As a pigment

This xanthophyll, like its sister compound zeaxanthin, is often used in food and supplements to give a yellow-red color. Lutein absorbs blue light, which makes it look yellow when there is a little of it and orange-red when there is a lot.

Many songbirds, such as the golden oriole, evening grosbeak, yellow warbler, common yellowthroat, and Javan green magpies, get lutein from what they eat and use it to color their feathers. However, birds like the American goldfinch and yellow canaries do not use lutein this way.

Role in human eyes

Lutein is found in a small part of the eye called the macula, which helps us see colors clearly. Scientists are still learning exactly how lutein works there.

Studies have shown that eating foods with lutein or taking supplements might help slow down a condition called age-related macular degeneration, especially for people who don’t get much lutein from their food. However, it’s not clear if lutein alone can prevent this condition.

Some research also suggests that getting enough lutein might lower the chance of developing cataracts, which are cloudy spots in the eye. But more studies are needed to know for sure.

In foods

Lutein is a natural part of our diet and can be found in orange-yellow fruits, flowers, and leafy vegetables. On average, adults in the United States eat about 1.7 mg of lutein each day, though there is no official recommendation for how much to eat. Some good sources of lutein include paprika, frozen spinach, sweet potato leaves, dandelion greens, red cayenne pepper, and turnip greens.

Lutein can also be used as a food additive and is taken from the petals of Mexican marigold flowers. It is allowed in some countries but not as a food coloring in the United States, though it can be used in animal feed and as a dietary supplement. Eating too much lutein can cause a bronzing of the skin, but this is not harmful.

Commercial value

Lutein is used in many different products, such as medicines, vitamins, food, pet food, and animal and fish feed. For example, it helps give chicken egg yolks their yellow color and makes fish in farms look more like fish from the wild. Many vitamin products contain lutein because people believe it helps keep eyes healthy.