8 Nutrients That Will Optimize Your Eye Health
By Atli Arnarson, PhD
Your eyesight is probably the most important of your five senses.
Eye health goes hand-in-hand with general health, but a few nutrients are especially important for your eyes.
These nutrients help maintain eye function, protect your eyes against harmful light, and reduce the development of age-related degenerative diseases.
Here are 8 nutrients that benefit your eyes.
Overview of Common Eye Diseases
Your risk of developing an eye disease increases as you get older. The most common eye diseases include:
- Cataracts. A condition in which your eyes become clouded. Age-related cataracts are a leading cause of vision impairment and blindness around the world.
- Diabetic retinopathy. Associated with diabetes and a major cause of visual impairment and blindness, retinopathy develops when high blood sugar levels damage the blood vessels in your retina.
- Dry eye disease. A condition marked by insufficient tear fluid, which causes your eyes to dry up and leads to discomfort and potential visual problems.
- Glaucoma. A group of diseases characterized by progressive degeneration of your optic nerve, which transfers visual information from eyes to brain. Glaucoma may cause poor eyesight or blindness.
- Macular degeneration. The macula is the central part of your retina. Age-related macular degeneration (AMD) is one of the main causes of blindness in developed countries.
Although your risk of getting these conditions depends to some extent on your genes, your diet may also play a major role.
The most common eye conditions include cataracts, macular degeneration, glaucoma, and diabetic retinopathy. Your risk of developing these diseases depends on your age, genetics, chronic diseases, and lifestyle.
1. Vitamin A
This vitamin is essential for maintaining your eyes' light-sensing cells, also known as photoreceptors.
If you don't consume enough vitamin A, you may experience night blindness, dry eyes, or even more serious conditions, depending on the severity of your deficiency (2 Trusted Source).
Vitamin A is only found in animal-derived foods. The richest dietary sources include liver, egg yolks, and dairy products.
However, you can also get vitamin A from antioxidant plant compounds called provitamin A carotenoids, found in high amounts in some fruits and vegetables.
Provitamin A carotenoids provide around 30% of people's vitamin A requirements, on average. The most efficient of them is beta-carotene, which is found in high amounts in kale, spinach, and carrots (3 Trusted Source).
Vitamin A deficiency may lead to night blindness and dry eyes. Vitamin A is only found in animal-derived foods, but your body can convert certain plant-based carotenoids into vitamin A.
2–3. Lutein and Zeaxanthin
Lutein and zeaxanthin are yellow carotenoid antioxidants known as macular pigments.
They are concentrated in the macula, the central part of your retina, which is a layer of light-sensitive cells on the back wall of your eyeball.
Controlled studies show that intake of lutein and zeaxanthin is proportional to their levels in your retina (5 Trusted Source).
One observational study in middle-aged and older adults noted that consuming 6 mg of lutein and/or zeaxanthin per day significantly reduced the risk of AMD.
The researchers also discovered that those with the highest intake of lutein and zeaxanthin had a 43% lower risk of macular degeneration, compared to those with the lowest intake (6 Trusted Source).
However, the evidence is not entirely consistent. One meta-analysis of six observational studies suggests that lutein and zeaxanthin only protect against late-stage AMD — not its early development stages (7 Trusted Source).
Lutein and zeaxanthin usually occur together in foods. Spinach, swiss chard, kale, parsley, pistachios, and green peas are among the best sources (8 Trusted Source).
What's more, egg yolks, sweet corn, and red grapes may also be high in lutein and zeaxanthin (9 Trusted Source).
In fact, egg yolks are considered one of the best sources due to their high fat content. Carotenoids are better absorbed when eaten with fat, so it's best to add some avocado or healthy oils to your leafy vegetable salad (10 Trusted Source, 11 Trusted Source, 12 Trusted Source).
A high intake of lutein and zeaxanthin may reduce your risk of eye diseases, such as macular degeneration and cataracts.
4. Omega-3 Fatty Acids
The long-chain omega-3 fatty acids EPA and DHA are important for eye health.
DHA is found in high amounts in your retina, where it may help maintain eye function. It's also important for brain and eye development during infancy. Thus, DHA deficiency can impair vision, especially in children (13 Trusted Source, 14 Trusted Source, 15 Trusted Source, 16 Trusted Source).
One study in people with dry eyes revealed that taking EPA and DHA supplements daily for three months significantly reduced dry eye symptoms by increasing the formation of tear fluid (18 Trusted Source).
Omega-3 fatty acids may also help prevent other eye diseases. A study in middle-aged and older adults with diabetes found that taking at least 500 mg of long-chain omega-3s daily may reduce the risk of diabetic retinopathy (21 Trusted Source).
In contrast, omega-3 fatty acids are not an effective treatment for AMD (22).
The best dietary source of EPA and DHA is oily fish. Additionally, omega-3 supplements derived from fish or microalgae are widely available.
Getting adequate amounts of the long-chain omega-3 fatty acids EPA and DHA from oily fish or supplements may reduce your risk of several eye diseases — especially dry eyes.
5. Gamma-Linolenic Acid
Gamma-linolenic acid (GLA) is an omega-6 fatty acid found in small amounts in the modern diet.
The richest sources of GLA are evening primrose oil and starflower oil.
Some evidence suggests that taking evening primrose oil may reduce the symptoms of dry eye disease.
One randomized controlled study gave women with dry eyes a daily dose of evening primrose oil with 300 mg of GLA. The study noted that their symptoms improved over a 6-month period (25 Trusted Source).
GLA, which is found in high amounts in evening primrose oil, may reduce symptoms of dry eye disease.
6. Vitamin C
Your eyes require high amounts of antioxidants — more so than many other organs.
The antioxidant vitamin C appears to be especially important, although controlled studies on its role in eye health are lacking.
The concentration of vitamin C is higher in the aqueous humor of the eye than in any other body fluid. The aqueous humor is the liquid that fills the outermost part of your eye.
The levels of vitamin C in the aqueous humor are directly proportional to its dietary intake. In other words, you can increase its concentration by taking supplements or eating foods rich in vitamin C (26 Trusted Source, 27 Trusted Source).
Observational studies show that people with cataracts tend to have a low antioxidant status. They also indicate that people who take vitamin C supplements are less likely to get cataracts (28 Trusted Source, 29 Trusted Source).
While vitamin C appears to play a protective role in your eyes, it's unclear whether supplements provide added benefits for those who aren't deficient.
Vitamin C is necessary for your eye health, and getting enough of this antioxidant may protect against cataracts.
7. Vitamin E
Vitamin E is a group of fat-soluble antioxidants that protect fatty acids from harmful oxidation.
Since your retina has a high concentration of fatty acids, adequate vitamin E intake is important for optimal eye health (16 Trusted Source).
Although severe vitamin E deficiency may lead to retinal degeneration and blindness, it's unclear whether supplements provide any additional benefits if you're already getting enough from your diet (31 Trusted Source, 32 Trusted Source).
One analysis suggests that consuming more than 7 mg of vitamin E daily may reduce your risk of age-related cataracts by 6% (33 Trusted Source).
In contrast, randomized controlled studies indicate that vitamin E supplements do not slow or prevent the progression of cataracts (34).
Vitamin E deficiency may lead to visual degeneration and blindness. For those who aren't deficient, supplements probably won't provide an added benefit.
Your eyes contain high levels of zinc (36 Trusted Source).
Zinc is a part of many essential enzymes, including superoxide dismutase, which functions as an antioxidant.
It also appears to be involved in the formation of visual pigments in your retina. For this reason, zinc deficiency may lead to night blindness (37 Trusted Source).
In one study, older adults with early macular degeneration were given zinc supplements. Their macular deterioration slowed, and they maintained their visual sharpness better than those who received a placebo (38 Trusted Source).
However, further studies are needed before strong conclusions can be reached.
Zinc plays an important role in eye function. One study suggests that supplements may slow the early development of macular degeneration in older adults.
The Bottom Line
Healthy lifestyle habits, such as a wholesome diet and regular exercise, may help prevent many chronic diseases — including eye conditions.
Getting enough of the nutrients listed above may help reduce your risk. Other vitamins may also play a role in eye health.
However, don't neglect the rest of your body. A diet that keeps your whole body healthy will likely keep your eyes healthy, too.
Reposted with permission from our media associate Healthline.
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If weather is your mood, climate is your personality. That's an analogy some scientists use to help explain the difference between two words people often get mixed up.
Size Matters<p>Climates are a bit like woven tapestries. The big picture is important, no question. But so are all the seemingly minor details found inside the larger whole.</p><p><a href="https://research-information.bris.ac.uk/en/persons/tommaso-jucker" target="_blank">Tommaso Jucker</a> is an environmental scientist at the University of Bristol. In an email, Jucker says he'd define the term microclimate as "the suite of climatic conditions (temperature, rainfall, humidity, solar radiation) measured in localized areas, typically near the ground and at spatial scales that are directly relevant to ecological processes."</p><p>We'll talk about that last bit in a minute. But first, there's another criteria to discuss. According to some researchers, a microclimate — by definition — must differ from the larger area that surrounds it.</p><p><a href="https://www.cfc.umt.edu/research/paleoecologylab/publications/Davis_et_al_2019_Ecography.pdf" target="_blank">Forests</a> provide us with some great examples. "The climate near the ground in a tropical rainforest is dramatically different from the climate in the canopy 50 meters [164 feet] above," says University of Montana ecologist <a href="https://www.cfc.umt.edu/personnel/details.php?ID=1110" target="_blank">Solomon Dobrowski</a> in an email. "This vertical gradient among other factors allows for the staggering biodiversity we see in the tropics."</p><p>Likewise, scientists observed that a 2015 partial <a href="https://animals.howstuffworks.com/insects/bees-stopped-buzzing-during-2017-solar-eclipse.htm" target="_blank">solar eclipse</a> caused the air temperature of an Eastern European meadow to <a href="https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/wea.2802" target="_blank">change more dramatically</a> than it did in a nearby forest. That's because trees provide not only shade, but their leaves also reflect solar radiation. At the same time, forests tend to reduce wind speeds.</p><p>All those factors add up. A 2019 review of 98 wooded places — spread out across five continents — found that forests are 7.2 degrees Fahrenheit (4 degrees Celsius) <a href="https://natureecoevocommunity.nature.com/posts/47363-forests-protect-animals-and-plants-against-warming" target="_blank">cooler on average</a> than the areas outside them.</p><p>Now if you hate the cold, don't worry; there's a cozy exception to the rule. According to that same study, forests are usually 1.8 degrees Fahrenheit (1 degree Celsius) warmer than the external environment during the wintertime. Pretty cool.</p>
A Bug's Life<p>When does a microclimate stop being, well, micro? In other words, is there a maximum size we should be aware of when discussing them?</p><p>Depends on who you ask. "In terms of horizontal scale, some have defined 'microclimate' as anything that is less than 100 meters [328 feet] in range," Jucker says. "I'm personally less prescriptive about this."</p><p>Instead, he says the "scale at which we want to measure [a particular] microclimate" ought to be "dictated" by the questions we're trying to answer.</p><p>"If I want to know how temperature affects the photosynthesis of a leaf, I should be measuring temperature at centimeter scale," Jucker explains. "If I want to know if and how temperature affects the habitat preference of a large, mobile mammal, it's probably more relevant to capture temperature variation across [tens to hundreds] of meters."</p><p>For instance, solitary plants have the power to generate itty-bitty microclimates. Just ask <a href="https://www.colorado.edu/geography/peter-blanken-0" target="_blank">Peter Blanken</a>, a geography professor at the University of Colorado, Boulder and the co-author of the 2016 book, "<a href="https://amzn.to/2XN6FT8" target="_blank">Microclimate and Local Climate</a>."</p>
The urban heat island effect is a good example of how microclimates work. NOAA
Microclimates on a Grand Scale<p>It's no secret that our planet is going through some rough times at the macro level. The global temperature is <a href="https://climate.nasa.gov/vital-signs/global-temperature/" target="_blank">climbing</a>; nine out of the <a href="https://www.noaa.gov/news/2019-was-2nd-hottest-year-on-record-for-earth-say-noaa-nasa" target="_blank">10 hottest years on record</a> have occurred since 2005. And by one recent estimate, roughly 1 million species around the world are <a href="https://ipbes.net/sites/default/files/2020-02/ipbes_global_assessment_report_summary_for_policymakers_en.pdf" target="_blank">facing extinction</a> due to human activities.</p><p>"One of the big questions that ecologists and environmental scientists are trying to answer right now is how will individual species and whole ecosystems respond to rapid climate change and habitat loss," says Jucker. "...To me, [microclimates are] a key component of this research — if we don't measure and understand climate at the appropriate scale, then predicting how things will change in the future becomes a lot harder."</p><p>Developers have long understood the impact small-scale climates have on our daily lives. <a href="https://science.howstuffworks.com/environmental/green-science/urban-heat-island.htm#pt0" target="_blank">Urban heat islands</a> are cities that have higher temperatures than neighboring rural areas.</p><p>Plants release vapors that can moderate local climates. But in cities, natural greenery is often scarce. To make matters worse, plenty of our roads and buildings have a bad habit of absorbing or re-emitting heat from the sun. <a href="https://www.google.com/books/edition/Microclimate_and_Local_Climate/LHUZDAAAQBAJ?hl=en&gbpv=1&bsq=urban%20heat%20island" target="_blank">Vehicle emissions</a> don't exactly help the situation.</p><p>Still, it's not like Boston or Beijing are thermal monoliths. Sometimes, the documented temperatures <a href="https://e360.yale.edu/features/can-we-turn-down-the-temperature-on-urban-heat-islands" target="_blank">within a single city</a> vary by 15 to 20 degrees Fahrenheit (8.3 to 11.1 degrees Celsius).</p><p>That's where metro parks and city trees come in. They have nice cooling effects on nearby neighborhoods. "Several cities around the world have developed programs to increase urban green spaces," says Blanken. "Tree planting programs and green roof programs, have been shown to lower surface temperatures, decrease air pollution and decrease surface water runoff (urban flash-flooding) in urban areas."</p>
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<div id="ecf36" class="rm-shortcode" data-rm-shortcode-id="c2dcc9d48a6cd61f247df1544539a783"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1290959314132361216" data-partner="rebelmouse"><div style="margin:1em 0">Naming heatwaves is a good idea—making the abstract concrete, the invisible visible. Why should hurricanes and wild… https://t.co/hDWgYb79Ob</div> — Ed Maibach (@Ed Maibach)<a href="https://twitter.com/MaibachEd/statuses/1290959314132361216">1596623660.0</a></blockquote></div>
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Bricks are a preferred building tool for their durability and resilience against heat and frost since they do not shrink, expand or warp in a way that compromises infrastructure. They are also reusable. What was unknown, until now, is that they can be altered to store electrical energy, according to a new study published in Nature Communications.
The scientists behind the study figured out a way to modify bricks in order to use their iconic red hue, which comes from hematite, an iron oxide, to store enough electricity to power devices, Gizmodo reported. To do that, the researchers filled bricks' pores with a nanofiber made from a conducting plastic that can store an electrical charge.
The first bricks they modified stored enough of a charge to power a small light. They can be charged in just 13 minutes and hold 10,000 charges, but the challenge is getting them to hold a much larger charge, making the technology a distant proposition.
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