When considering vitamins and supplements for improving eye health and vision, vitamin-A and beta carotene –a carotenoid (pigment) from orange plants and starches such as carrots and sweet potatoes — come to mind.

That is because they have long been known by nutritional scientists and health experts as linked to improved eye health –indeed, vitamin A is so integral to general eye health that a deficiency in it can lead to blindness and fatal infections.

Luckily, deficiencies in vitamin A are exceedingly rare.

Lutein is a vitamin-A-like carotenoid often found alongside vitamin-A in foods such as dark leafy greens (kale, spinach, and chard), broccoli, squash, egg yolks, grapes, and pistachios.

Numerous controlled trials and meta-analyses indicate that, like vitamin-A and beta carotene, it is vital to eye function and health, which is why you should supplement with lutein.

History and Synthesis of Lutein

The part of the retina responsible for producing sharp detail in our focal vision –i.e., in our center of awareness — is called the macula lutea. It is in the retina’s center and is itself yellow, working to filter blue light and enhance our perception of color.

As stated in JAMA Opthalmology, this portion of the retina has been discussed in the scientific literature since 1798.

In his groundbreaking 1945 article, “Human Vision and the Spectrum,” George Wald discovered that the yellow pigment in the human eye absorbed wavelengths between 430 and 490 nm, with maximum absorption at 465 nm.

He was also the first to extract xanthophylls from the human retina and found them concentrated in the macula. Later research confirmed that xanthophylls were the source of the macula’s yellow color.

Xanthophylls are a subclass of carotenoids, a large group of plant pigments responsible for the vibrant colors found in fruits, vegetables, autumn leaves, salmon, canaries, and flamingos.

These pigments play a vital role in plants as energy sinks, facilitating photosynthesis with chlorophyll. Carotenoids are linear hydrocarbons, while xanthophylls are their oxygenated form.

In the 1980s, Bone and his team identified lutein and its structural isomer, zeaxanthin, as the specific xanthophylls in the retina.

Around the same time, Snodderly and his colleagues found the xanthophyll pigment in primates’ Henle fiber layer. This research laid the foundation for understanding lutein and zeaxanthin’s crucial role in eye health.

In short, one can say that lutein is a molecule vital to the production of fine-grained color perceptions, which is an ability that degrades as we age.

How Does Lutein Work?

The precise functional roles of macular carotenoids, such as lutein and zeaxanthin, have yet to be fully established. However, as further stated in JAMA Ophthalmology, their known biological, optical, and photochemical properties allow us to infer some of their potential functions in the human eye.

These include blue-light filtration effects, glare reduction, minimization of chromatic aberration, improved fine detail distinction, contrast enhancement, and maintaining cellular health by neutralizing reactive oxygen species.

When light enters the eye, different things can happen. Some light can be lost due to imperfections in the eye’s structure or scattered by the anterior media.

Another light is deliberately filtered out by the eye’s design. For example, almost all UV-B (320 to 290 nm) and UV-A (320–400 nm) light is absorbed by the cornea and the lens, respectively.

The macular pigment, which has a peak absorbance of 460 nm, absorbs most of the slightly longer-wave (blue) light (400–520 nm) that reaches the macula.

This filtering system reduces chromatic aberration, resulting in better visual acuity.

Glare is common among older individuals, people with retinal diseases or cataracts, and others without obvious predispositions.

One possible explanation for this is the reduced presence of macular pigment in these individuals. In addition, macular pigment’s optical properties suggest it may help reduce glare by absorbing polarized light.

This glare reduction could also be connected to the increased sensitivity to glare in people with low macular pigment levels.

Moreover, the macular pigment may enhance visual sensitivity. In one study, older subjects with high macular pigment density exhibited similar visual sensitivity to younger subjects after correcting for lens density. This suggests that higher macular pigment levels could be associated with better visual sensitivity in older individuals.

Another essential proposed function of macular pigment is neutralizing reactive oxygen species. The retina, especially the photoreceptor outer segments, contains high concentrations of polyunsaturated fatty acids susceptible to photooxidation.

The outer retina also has a high oxygen tension, almost that of arterial blood. This combination of vulnerable substrates, rich oxygen supply, and high-energy blue light creates ideal conditions for oxidative damage.

Carotenoids, including lutein and zeaxanthin, are potent scavengers of free radicals and are particularly effective at neutralizing singlet oxygen. In addition, by residing in the lipid-rich membranes, carotenoids likely protect the outer retina’s polyunsaturated fatty acid–rich membranes from damage.

The Benefits of Supplementing with Lutein

Researchers from the journal Ophthalmology aimed to determine whether supplementing lutein and zeaxanthin could improve macular pigment and visual function in patients with early age-related macular degeneration (AMD).

In a study designed to investigate the effects of lutein and zeaxanthin on early age-related macular degeneration (AMD), 108 participants aged 50 to 79 years were randomly assigned to receive different doses of lutein, lutein, and zeaxanthin or a placebo for 48 weeks.

The study’s main goal was to measure the density of the macular pigment, an essential part of maintaining good vision.

Additional measurements included visual acuity, contrast sensitivity, photo recovery time, and Amsler grid test results.

The study found that participants who took higher doses of lutein or a combination of lutein and zeaxanthin experienced a significant increase in macular pigment density. Moreover, these improvements were more pronounced in individuals with lower initial pigment levels.

By the end of the study, participants in the 20-mg lutein group showed a trend towards improved visual acuity and better contrast sensitivity compared to the placebo group.

The increase in macular pigment density was also positively linked to improvements in visual acuity and contrast sensitivity.

This suggests that lutein and zeaxanthin supplementation may help enhance visual function in people with early AMD. In addition, the increase in MPOD was positively related to the reduction in BCVA and the increases in CS at four spatial frequencies.

In short, supplementation with lutein and zeaxanthin improved macular pigment in patients with early AMD, which played a causative role in enhancing visual function.

This makes sense of further research from the journal Nutrients, which highlights the importance of maintaining macular health for normal visual function.

The risk of light-induced retinal damage is heavily influenced by factors such as wavelength, exposure time, and power level. Interestingly, 440 nm blue light requires 100 times less energy to cause damage than 590 nm orange light.

Nutrient researchers also found an inverse relationship between macular pigment density and lens density in the eye, suggesting that macular pigment may indicate xanthophylls in the lens.

Lutein, zeaxanthin, and mesozeaxanthin are crucial in protecting eye structures from harmful doses of blue visible light (400–500 nm) due to their ability to absorb this radiation.

Their unique structures enable this optical filtration, which is particularly vital since short-wavelength (blue) light is highly reactive and could exacerbate photooxidative degeneration in the most sensitive neurosensory layers of the retina.

In each case, these are results corroborated by research from the British Journal of Nutrition and the American Journal of Ophthalmology.

Dosages and Side-effects

Given the necessity of lutein and zeaxanthin for eye health, it is virtually impossible to experience side effects while consuming it through food or supplements.

Given its abundance in whole foods and its responsibility for maintaining the integrity of the physical structures of the eye, it is improbable for one to be deficient in it.

However, if one is allergic to (or dislikes) the foods lutein is commonly found in, one should supplement with 4 to 8 milligrams of lutein daily.

Lutein and zeaxanthin are essential carotenoids crucial in maintaining eye health and vision, especially as we age.

These powerful antioxidants can be found in various whole foods, such as dark leafy greens, broccoli, squash, egg yolks, grapes, and pistachios.

Scientific research has demonstrated the potential benefits of supplementing with lutein and zeaxanthin in enhancing visual function, reducing glare, and protecting the retina from harmful blue light.

Furthermore, studies have shown that higher macular pigment levels may be associated with better visual sensitivity, especially in older individuals.

Consuming lutein and zeaxanthin through food or supplements is generally safe, with minimal risk of side effects.

For those who may not consume enough lutein-rich foods or prefer supplementation, a daily dosage of 4 to 8 milligrams is recommended.

In a world where our eyes are constantly exposed to screens, and harsh lighting conditions, prioritizing eye health is more critical than ever.

By incorporating lutein and zeaxanthin into your diet or supplementation routine, you can take a proactive step toward maintaining your vision and overall eye health.