玉米黃質:健康益處和主要食物來源

What is zeaxanthin?

Zeaxanthin is a carotenoid found in the human eye. Two other carotenoids your eyes contain are lutein and meso-zeaxanthin.

Zeaxanthin is thought to be produced when your body breaks down other carotenoids, and you don't typically get it from your diet.

Carotenoids are fat-soluble antioxidant molecules that appear bright red, yellow, or orange. They are found in some algae, bacteria, fungi, plants, fruits and vegetables.

They are essential nutrients that you must get from your diet.

Of the 700 carotenoids found in nature, only about 20 are always present in the human body. Among them, zeaxanthin and lutein are mainly found in the human eye.

You can find zeaxanthin and lutein in a variety of fruits, vegetables, and animal products, such as egg yolks.

They belong to the class of carotenoid pigments called xanthophylls, which are abundant in plants and in the exposed structure of the human eye.

In scientific studies, zeaxanthin and lutein are often described together because of their overlapping functions in the eye and also because the body can convert lutein into zeaxanthin.

Zeaxanthin is concentrated in the center of the retina, while lutein is found in the peripheral areas of the retina. Together they form the macular pigment of the eye.

Both have antioxidant benefits, although zeaxanthin is the more potent antioxidant.

In humans, the most studied function of carotenoids is vision and their role in eye health and reducing the risk of eye disease.

Antioxidant and anti-inflammatory properties in eyes

Antioxidants protect the body from oxidative stress caused by highly reactive molecules called free radicals or oxidants. They reduce the levels of free radicals and inflammation in the body.

Excessive production of free radicals and chronic inflammation in the body are associated with the development of diseases such as:

Age-related macular degeneration (AMD)
Dementia Cancer Additionally, exposure to blue light waves has been shown to increase the production of free radicals and oxidative stress in the eyes, posing a potential threat to eye health.

Research shows that zeaxanthin reduces oxidative stress and damage to the eyes by absorbing blue light, thereby reducing inflammation and the risk of eye disease.

In fact, the most light-exposed layer of the eye contains about 75% zeaxanthin, which absorbs up to 90% of blue light to protect the retina from light-induced damage.

Reduce the risk of eye disease

Many studies show that zeaxanthin plays an important role in eye health throughout life. In particular, it is associated with a lower risk of age-related eye diseases, including AMD, cataracts, and glaucoma.

These eye diseases cause damage to the macula of the eye, the area responsible for fine vision. The macula is also where carotenoids, zeaxanthin and lutein are stored.

Cataracts, glaucoma, and diabetic retinopathy are all eye diseases caused by damage to the nerves in the eyes caused by long-term high blood sugar, which can occur in people with diabetes.

AMD is the leading cause of blindness in Americans over the age of 40.

The antioxidant properties of zeaxanthin help prevent oxidative stress, reduce eye inflammation, and protect the macula from damage.

Zeaxanthin also plays an important role in eye development during fetal development and optimal vision in early adulthood.

A diet rich in zeaxanthin and other antioxidants may increase the density of macular pigment and reduce the risk of eye disease.

May improve brain health and cognitive abilities in addition to

In addition to its role in vision, zeaxanthin is found in areas of the brain associated with cognition, motor coordination, and decision-making.

Compared to its benefits for the eyes, there is less research on the benefits of zeaxanthin for the brain.

Still, studies show that Alzheimer's patients with higher levels of zeaxanthin have lower mortality rates.

Other research suggests that taking 2 mg of zeaxanthin daily may not improve cognitive function in people with Alzheimer's disease.

It's unclear how this finding relates to dietary intake of zeaxanthin. Researchers estimate that the average daily intake of zeaxanthin in the United States is 1.3 mg, but may be as high as 25 mg in some South Pacific populations.

More research is needed on the relationship between zeaxanthin, cognition, and Alzheimer's disease.

UV protection and skin health

Zeaxanthin is found in large amounts in human skin.

In the eyes and skin, zeaxanthin absorbs harmful blue light waves and protects against oxidative stress caused by free radicals.

Many factors influence skin aging and sensitivity, including nutritional deficiencies and ultraviolet (UV) radiation from the sun.

Some symptoms of skin aging include:

  • dry or rough
  • wrinkle
  • lose elasticity
  • Discoloration

Research shows that zeaxanthin’s UV protection can improve signs of skin aging. People gain these benefits by eating a zeaxanthin-rich diet and using skin creams containing zeaxanthin and other antioxidants.

Other potential health benefits

Zeaxanthin may also provide a range of other health benefits, including:

Can protect kidney health. Low levels of the lutein carotenoids, including zeaxanthin, are associated with an increased risk of kidney disease. Eating the zeaxanthin found in egg yolks may also provide antioxidant benefits to people with chronic kidney disease.
Can treat liver disease. Zeagin dipalmitate, extracted from goji berries, appears to protect the liver by reducing inflammation and helping to prevent liver scarring caused by liver disease. Scientists are exploring it as a potential treatment.
Improve communication within cells. Zeaxanthin and carotenoids may play a role in intercellular communication and homeostasis, the balanced physical and chemical state required for good health. More research is needed in this area.
So far, scientists have explored most of zea yellow's benefits for vision and eye health.

main food sources

Zeaxanthin occurs naturally in a variety of fruits and vegetables. Dark leafy green vegetables are rich in zeaxanthin.

Scientific information often lists foods containing zeaxanthin and lutein as one category, rather than listing them separately. This may be because lutein can be converted into the carotenoid meso-zeaxanthin in the eye, but also because zeaxanthin is low in the human diet.

Zeaxanthin is the main carotenoid in wolfberry. Fruits and seeds are rich sources.

Corn, egg yolks, and breast milk are other bioavailable sources, meaning your body can easily absorb the zeaxanthin in these foods.

Here is a list of other foods rich in zeaxanthin and lutein, including the amount of each per 100 grams:

  • Raw spinach: 12.2 mg
  • Raw pistachios: 2.9 mg
  • Raw green peas: 2.5 mg
  • Lettuce, raw: 2.3 mg
  • Zucchini, cooked: 2.3 mg
  • Brussels sprouts, boiled: 1.2 mg
  • Raw broccoli: 1.4 mg
  • Pumpkin, cooked: 1.0 mg
  • Cooked asparagus: 0.8 mg
  • Raw carrots: 0.3 mg

Currently, there is no recommended daily intake of zeaxanthin. However, intake of at least 2 mg appears to provide some health benefits.

Research shows that when people consume 5-6 mg of zeaxanthin per day, the risk of AMD is lowest and cataract growth slows.

Through diet alone, you can get 5-10 mg of zeaxanthin and lutein from a variety of whole foods, including orange peppers, corn, and eggs.

There are currently few studies examining its effects in other parts of the body.

Zeaxanthin Supplements

Zeaxanthin-containing supplements and eye health supplements are becoming more and more popular.

Studies show that taking zeaxanthin increases the density of macular pigment in the eyes.

One study had people take zeaxanthin supplements for 6 to 24 months. Studies have found that 36-95% of humans have increased macular pigment density. Interestingly, this reaction varies from person to person.

potential risks

Although scientific findings are inconclusive, zeaxanthin appears to be generally safe.

Taking lutein (including zeaxanthin) at higher doses may cause some concern, but more research is needed.

Other studies estimate that a daily intake of 0.34 mg per pound of body weight (0.75 mg per kilogram) may be safe. For a person weighing 154 pounds (70 kilograms), this is equivalent to 53 milligrams of zeaxanthin.

High levels are often difficult to absorb through diet alone. The average daily intake of zeaxanthin through diet is only 1.3 mg.

generalize

Zeaxanthin is an important molecule in the eyes and is essential for protecting the eyes from damage throughout life. It is fat-soluble and a member of the carotenoid family.

One of three carotenoids found in the human eye that absorb harmful blue light, it has antioxidant and anti-inflammatory properties that may reduce the risk of age-related macular degeneration, glaucoma, cataracts and diabetic retinopathy.

You can get it in your diet by eating a variety of whole foods and taking supplements.

There is no recommended daily intake for zeaxanthin. Scientists need to do more research to find a safe and beneficial dose for humans.

Scientists need to do more research to determine what doses of zeaxanthin supplements are safe and beneficial.

Higher macular pigment density is associated with a lower risk of AMD.

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