Lutein

Category: Carotenoids

Lutein is a naturally occurring xanthophyll carotenoid, a group of plant pigments found especially in green leaves and some yellow, orange, and red plant foods. In green plants, lutein is often hidden visually by the much stronger green colour of chlorophyll.

Unlike beta-carotene, lutein is not a provitamin A carotenoid, meaning the human body does not primarily use it to produce vitamin A. Instead, lutein has its own biological roles, particularly as an antioxidant and as one of the carotenoids concentrated in the human eye.

The human body cannot manufacture lutein, so it must be obtained through the diet.

Lutein and Eye Health

Eye health is the area in which lutein has been studied most extensively.

Lutein and the closely related carotenoid zeaxanthin accumulate in the retina, particularly in the macula. Together, they are major components of macular pigment.

Lutein may help:

• Filter some high-energy blue light reaching the retina
• Provide antioxidant protection within eye tissues
• Protect cells against oxidative stress
• Support normal visual function
• Maintain macular pigment

The National Eye Institute notes that lutein and zeaxanthin are found in the retina and may act as antioxidants while helping filter potentially damaging wavelengths of light.

Research, including the AREDS2 studies, has also investigated lutein and zeaxanthin in relation to age-related macular degeneration (AMD). This does not mean lutein prevents or cures AMD, and specialized AREDS2 supplements are intended for particular groups of people rather than the general population.

Antioxidant Protection

Lutein also functions as an antioxidant.

Normal metabolism and environmental exposures can produce reactive molecules commonly called free radicals. When their production exceeds the body's antioxidant defences, oxidative stress can occur.

Lutein can contribute to antioxidant defence by helping neutralize reactive molecules and protecting cellular components from oxidative damage.

This antioxidant activity is particularly relevant in tissues exposed to substantial amounts of light and oxygen, including the eyes.

Lutein Beyond the Eyes

Although eye health has the strongest research base, lutein is also being investigated for possible roles in other areas of health and wellness, including:

• Brain and cognitive health
• Skin health
• Cardiovascular health
• Healthy aging
• Protection against oxidative stress

Research in these areas continues, and associations between lutein intake or lutein status and health outcomes should not be interpreted as proof that lutein can prevent or treat specific diseases.

Native and Naturally Occurring Ontario Plants Containing Lutein

Ostrich Fern — Matteuccia struthiopteris

Ostrich fern is native to Ontario, and its young emerging shoots are the familiar edible fiddleheads.

Research analyzing fiddlehead tissue has directly identified lutein along with several other carotenoids, including zeaxanthin and beta-carotene.

Fiddleheads provide an interesting local example of how edible plants can contain several different carotenoids rather than a single isolated compound.

Only correctly identified edible fiddleheads should be consumed. Proper cleaning and cooking are important because raw or undercooked fiddleheads can cause foodborne illness.

Lowbush Blueberry — Vaccinium angustifolium

Lowbush blueberry is native to Ontario and belongs to the Vaccinium genus, in which lutein and other carotenoids have been identified.

Although blueberries are better known for their anthocyanins—the pigments largely responsible for their blue-purple colour—their broader phytochemical profile also includes carotenoids.

Plants That Can Be Grown Indoors Year-Round

Sweet Basil — Ocimum basilicum

Sweet basil is a particularly practical indoor source because it grows quickly, responds well to repeated harvesting, and can be grown in soil or hydroponically.

Research has identified lutein as one of the important carotenoids found in basil leaves.

Regular harvesting of fresh leaves makes basil useful for incorporating small amounts of fresh plant material into meals throughout the year.

Peppermint — Mentha × piperita

Peppermint contains lutein among the pigments naturally present in its leaves.

It is well suited to indoor growing because it can tolerate repeated harvesting and can be maintained in relatively small spaces with adequate light.

Peppermint would not normally be eaten in quantities comparable with leafy vegetables, but fresh leaves can still contribute plant compounds as part of foods and beverages.

Hot Peppers — Capsicum species

Hot peppers contain lutein, although the amount can vary considerably according to species, cultivar, growing conditions and stage of ripeness.

Lutein can be particularly prominent in immature green peppers. As peppers ripen and change colour, their carotenoid composition also changes.

Hot peppers can be grown indoors year-round with sufficient light, making them a practical small-space source of several different carotenoids.

Carolina Reaper — Capsicum chinense

Carolina Reaper belongs to Capsicum chinense, a species in which lutein has been identified.

As with other peppers, carotenoid composition changes as the fruit develops and ripens.

Carolina Reaper is an extremely hot pepper, so it should not be viewed as a practical way of consuming large amounts of lutein. Even very small quantities can produce intense heat and irritation.

Narrowleaf Plantain — Plantago lanceolata

Narrowleaf plantain contains lutein as part of the carotenoid pigments present in its leaves and involved in photosynthesis.

Young leaves can be grown and harvested in relatively small spaces. As the leaves mature, they generally become tougher and more fibrous.

Dandelion — Taraxacum officinale

Dandelion leaves are a notable source of lutein and zeaxanthin.

Dandelion is particularly useful from a small-space growing perspective because the leaves can be harvested while the plant continues growing. It can be maintained indoors with sufficient light and provides edible leafy material alongside a variety of vitamins, minerals and phytochemicals.

Tobacco — Nicotiana tabacum

Tobacco leaves contain lutein as one of the carotenoid pigments involved in photosynthesis.

Its inclusion here is for plant-compound identification only. The presence of lutein does not make tobacco an appropriate nutritional source. Tobacco contains nicotine and other potentially harmful compounds and should not be consumed as a source of lutein.

Lutein and Indoor Growing

Lutein provides another example of how a relatively small indoor growing space can produce plants containing useful nutrients and phytochemicals throughout the year.

Leafy plants are particularly interesting because lutein plays an important role within their photosynthetic tissues. Growing plants for repeated leaf harvesting can therefore provide fresh plant material without necessarily requiring large growing areas or waiting for fruit production.

Growing several different edible plants also provides a broader mixture of carotenoids, vitamins, minerals, polyphenols and other naturally occurring plant compounds rather than focusing on one compound alone.

Improving Lutein Absorption

Lutein is fat-soluble, so the amount absorbed from food can be influenced by how the food is eaten.

Consuming lutein-containing vegetables and herbs with a source of dietary fat can improve carotenoid absorption. This does not require large amounts of fat; including some fat as part of a balanced meal can help the digestive system absorb fat-soluble carotenoids.

Food preparation can also influence carotenoid availability. Chopping and cooking can sometimes make carotenoids more accessible by breaking down plant cell structures, although preparation can also reduce some heat-sensitive nutrients.

This is another reason why eating plants in different ways—fresh, lightly cooked and incorporated into meals—can contribute to dietary variety.

A Wellness Perspective

Lutein is a good example of how individual plant compounds work as part of a much larger nutritional picture.

A plant containing lutein will normally contain many other compounds at the same time, including other carotenoids, chlorophylls, vitamins, minerals, fibre and phytochemicals.

For health and wellness, the goal does not need to be consuming as much lutein as possible or finding a single "best" source. A more practical approach is eating a varied diet containing different edible plants.

Indoor growing can make some of those plants available throughout the year, even for people who do not have access to a traditional outdoor garden.

Learning what our plants contain can help us better understand the nutritional choices available to us and how even small growing spaces can become part of a broader approach to health and wellness.

Disclaimer

This Wellness Profile is for educational and informational purposes only and is not medical advice. Plant compounds and foods can interact with medications, medical conditions and individual sensitivities. Proper plant identification and food-safety practices are essential, particularly when consuming wild plants. Tobacco should not be used as a dietary source of lutein. Supplements should not be used to diagnose, treat, cure or prevent a medical condition without guidance from an appropriate healthcare professional.