Vision and Eye Health: A Reflection of General Health
Vision and Eye Health: A Reflection of General Health
By Nicole Crane, B.S., NTP
You may have heard the saying “the eyes are the window into the soul.” Did you know that the eyes can also give us insight into a few very important aspects of our overall health? For healthy eyes and healthy vision, we need good circulation, especially through small capillaries that bring blood, nutrients and oxygen to the eyes. We also need healthy fats, especially omega 3 fats, which many people do not get from diet. These fats keep the eyes moist and support nerve communication. Nerve health is a critical aspect of vision and eye health. The eye must be able to take in all the sensory information in the environment and send it to the brain. We need our optic nerve and other nerves of the eye to be healthy and energized for proper signals to be passed back and forth. We also need nutrients that many of us just don’t get enough of, like active vitamin A and zinc. The eyes also reflect the body’s ability to detoxify and keep tissues clear of things that can build up, like cataracts. They eyes can tell us a lot about our overall health, and when they eyes are unhealthy, chances are the same poor health is being reflected elsewhere in the body. Let your eyes do the talking for the rest of the body. When you support vision and eye health, know that you are also supporting nerve function, inflammation, circulation and more throughout the body.
The eyes are an amazing part of our anatomy, and are directly connected to the brain via the optic nerve. When we look into the mirror, we can see the iris, which is the colored part of the eye and the pupil, the circular black opening in the iris that lets light in. We can also see the sclera, the whites of the eye, the conjunctiva, a thin layer of tissue covering the front of the eye, but does not cover the cornea. We cannot actually see the cornea, the clear lens that covers and protects the iris, as it is translucent, but it is part of the external anatomy of the eye. The parts of the eyes that we cannot see are just as important. Most of the eyeball is filled with a clear gel called the vitreous. The vitreous is mostly made of water and collagen and a few trace protein and sugar molecules. Light enters the eye through the pupil and lens and travels to the back of the eye. Inside the back of the eye are special light-sensing cells that are collectively called the retina. The retina converts light into electrical impulses, a process which requires several essential nutrients. Within the center of the retina is a specialized, very sensitive area called the macula that is responsible for our central vision. Within the center of the macula is a small depression called the fovea which is responsible for our sharp central vision. It is this area that is essential to activities where visual details are important, like reading or driving. Each area of the eye has nutrients that are the most essential. There are also nutrients for general vision and eye to brain communication that are critical for healthy eyes as well. As we get older, there are a few conditions that plague the eyes and can have significant impacts on our sight. Age-related macular degeneration (AMD) is the leading cause of blindness in adults age 55 and older and affects more than 15 million people in the US. Cataracts, which is a clouding of the eye's natural lens, which is located behind the iris and the pupil. Cataracts are the most common cause of vision loss in people over age 40 and is the primary cause of blindness worldwide. Cataracts affect more than 22 million Americans over age 40. As the U.S. population ages, more than 30 million Americans are expected to have cataracts by the year 2020. Nutrition plays an essential role in the prevention of both these diseases, and many people are just not eating a nutrient dense diet that nourishes the eyes and protects our sight.
Vitamin A and Beta Carotene
Vitamin A is probably the most well-known nutrient for the eyes and vision, and for good reason. Vitamin A is actually a generic term for the family known as rentinoids. They are active and play a really essential role in healthy vision, especially in our retina. The retina is located in the back of the eye and when light passes through the lens of the eye, the retina converts the light into a nerve impulse that is received by the brain. When we do not have enough of active vitamin A, we do not properly activate our photoreceptors, which are nerve cells that convert light into nerve signals for the brain. When photoreceptors do not get activated, we cannot generate the nerve signals from the nerves in the eyes to the nerves in the brain. What does that actually mean? It means that without Vitamin A, the brain does not receive the signals that allow us to have vision and see what surrounds us. The first place that a Vitamin A deficiency presents itself is in our nighttime vision, when the eyes have to work harder to communicate to the brain. If you have trouble seeing at night, especially when driving, you may be missing active Vitamin A. There are some serious consequences to a long term vitamin A deficiency, When we are first deficient in vitamin A, first night blindness sets in, then we develop terrible dry eye, and eventually you could actually go blind. If you also have a zinc deficiency, it can be a double whammy for our vision, because we do not properly absorb and store Vitamin A without zinc. Missing these two nutrients can have a huge negative impact on our healthy vision. Zinc works closely with active Vitamin A, and this mineral is one of the more common mineral deficiencies in Americans. Up to 40% of Americans, especially among the elderly are zinc deficient, and over half of people in the U.S. are deficient in Vitamin A. 1,2 Furthermore, about 45-55% of the population, the same number who are Vitamin A deficient, are unable to convert beta carotene to active Vitamin A, so it is essential to get the active form from foods and/or supplements. 3 Zinc is a component of retinol-binding protein, a protein necessary for transporting vitamin A in the blood. Zinc is also required for the enzyme that converts retinol (vitamin A) to retinal. This latter form of vitamin A is necessary for the synthesis of rhodopsin, a protein in the eye that absorbs light and is involved in our ability to adapt to and be able to see in the dark. Zinc deficiency is associated with decreased release of vitamin A from the liver, which may contribute to symptoms of night blindness that are seen with zinc deficiency. Zinc is especially important for healthy vision as we get older. The macula is the portion of the retina in the back of the eye involved with central vision, and without zinc, Vitamin A and certain carotenoids, the risk of developing age-related macular degeneration is high. Not only is zinc found in high concentration in the macula, but the concentrations of zinc have been found to decline as we age. Zinc is actually essential for healthy, sharp perception in many of our senses, like taste, smell and sight. We experience a decline in the activities of some zinc-dependent retinal enzymes when we are older. Zinc is essential for a healthy retina and a healthy macula, and when these tissues are healthy, our vision is crisp and clear. 4 Vitamin A and zinc are a dynamic duo for vision and nerve communication between the eyes and the brain.
You have probably heard the term carotenoid before, but may not know exactly what it means. Carotenoids are red, orange and yellow pigments found mostly in fruits and veggies, even if they are green in color, like spinach! Be sure to support your vision with carotenoid rich foods like carrots, yams, leafy greens, beets and other wonderful healthy orange, yellow, red and purple fruits and veggies. .Beta carotene is the most popular and active member of the family of carotenoids. It has something known as Vitamin A activity, which means the body can convert it into active vitamin A. Not all carotenoids have vitamin A activity, such as lycopene and lutein. They are really important for the eyes still, but the body can not convert these into active A. It has been shown that supplemental beta carotene converts to vitamin A at a rate of 2:1, where when we get it from our diet, we convert it about 12:1. Other carotenoids, like alpha carotene converts at a rate of 24:1.5 Supplemental beta carotene clearly is absorbed and turned to vitamin A seemingly much more efficiently than from foods, but food sources provide a variety of carotenoids and other irreplaceable benefits. Carotenoids are nature's sunglasses. Beta carotene helps the eye filter and absorb all the colors of the visual spectrum, which are all the colors of the rainbow. Beta carotene, and the lesser known alpha carotene really help us see the world around us clearly and sharply. Other carotenoids offer vital support the health of the macula, which is part of the retina. Because the macula is yellow in color it absorbs blue and ultraviolet light that enter the eye, and acts as a natural sunblock for this part of the retina. This is especially important in today’s world because the light from our computers and cell phones is blue light. The macula acts like sunglasses for our central vision, which are the things you look directly at. The yellow color comes from its content of lutein and zeaxanthin, which are types of carotenoids. Zeaxanthin is found mostly at the macula, while lutein is found mostly elsewhere in the retina. Lutein and zeaxanthin are carotenoids that filter harmful high-energy blue wavelengths of light and act as antioxidants in the eye, helping protect and maintain healthy cells.
Of the 600 carotenoids we have discovered so far, only two are found in high quantities in the retina: lutein and zeaxanthin. The quantity of lutein and zeaxanthin in the macular region of the retina can be measured as macular pigment optical density (MPOD). MPOD is an effective biomarker for not only predicting disease but also for visual function. This means that when we have optimal levels of pigments from carotenoids like lutein and zeaxanthin in the retina, we have healthy eyes and healthy sight. By supporting the health of the retina and the macula, lutein and zeaxanthin play a significant role in warding off diseases like age-related macular degeneration and even cararacts.6 Unfortunately, the human body does not synthesize the lutein and zeaxanthin it needs, which is the reason why colorful vegetables are essential to good nutrition. If you aren’t getting enough leafy greens and other colorful veggies, consider supplementing with these essential nutrients. Six mg of lutein has been shown to reduce the risk of age related macular degeneration by 43% 7. Take steps now to nourish your eyes for healthy vision for a lifetime.
Vitamin C and E
Antioxidants are essential for the health of all our body tissues, and the eyes are no exception. Powerful antioxidants like Vitamin C and the family of Vitamin E (yes, there are 8 forms of Vitamin E!) protects the eyes from free radical damage which creates inflammation and can cause structural damage. These essential antioxidants also protect the large amount of fats in the brain and the eyes from oxidative damage, which interrupts their normal functioning. Antioxidants defend and protect the eyes from damage from all the toxins in our environment. Vitamin C helps us build collagen, which is the main structural protein in the eyes, and in the rest of the body as well. This versatile vitamin is essential for healthy circulation and allows our blood vessels to be flexible, which is very important for healthy blood pressure, especially in a place like the eyes. The blood vessels that lead into the eye are so small that they are only one red blood cell thick so it is important to protect these fragile vessels which are easily damaged. Capillaries are the main supplier of blood, oxygen and nutrients to the eyes, so it is really important that they stay healthy, flexible and strong. Vitamin C protects capillary beds and ensures a steady supply of nutrients to the eyes.
Vitamin E and Vitamin C are like best friends, or like a happily married couple. Each helps the other work better in the body. Vitamin E is also a powerful antioxidant and it gets recycled by Vitamin C so the body can use it again and again. There seems to be a protective effect against cataracts and macular degeneration when the body has optimal amounts of Vitamins C and E.8 We also need Vitamin E for healthy circulation and preventing the build up of plaque in the blood vessels that go into the eye and from the eyes to the brain. Vitamin E is also critical for the health of our nerves and can help the eyes communicate to the brain so we have healthy vision. Vitamin C and E are another dynamic due for the optimal health of the eyes and the brain.
N-Acetyl Cysteine (NAC) is a powerful antioxidant and it helps to build the body’s master antioxidant and detoxifier, known as glutathione. NAC plays a powerful role in protecting the integrity of tissues, works with the immune system to keep cells healthy and functioning normally and prevents sugar, medications and other harmful substances from doing damage. Because of the diverse role that NAC plays in the body, it helps to support the health of the eyes and vision. NAC clears away the waste material that can accumulate in the retina which damages the retinal pigmented epithelial cells (RPE) layer. This layer serves as the barrier between the retina and out blood supply and regulates the exchange of blood, oxygen, nutrients and waste products. Damage to the RPE cells has been implicated as a major cause of age related macular degeneration. As NAC protects the RPE layer, NAC plays a vital role in the health and protection of the macula. 9
When we eat sugar or carbohydrates in general, especially fructose sources, the body makes something called AGEs, and they attach to proteins in the body, like our structural proteins including those found in the eyes. This is often how cataracts begin to develop. NAC seems to have a protective effect and slows the buildup of AGEs, which spares the eyes from glycation, which can lead to crosslinking of proteins and the buildup of cataracts.10 NAC and glutathione appear to act as universal antioxidants, protecting our cellular lens membranes and the aqueous environment that makes up the whites of the eyes. NAC also seems to improve night vision. For many people, driving at night is particularly hazardous because of a phenomenon known as nighttime glare. Stoplights, streetlights and other car’s headlights can appear almost blinding to people who suffer from nighttime glare. The reason for this is light scatters when it hits the lens of the aged eye, resulting in bright streaks of light that impair vision and reduce the contrast between light and dark areas. It’s believed the NAC works like a windshield wiper to remove buildup on the lens of the aged eye resulting in a reduction in nighttime glare. NAC is one of the most versatile, protective nutrient for the eyes, shielding us from many of the things that damage our eyes, especially as we age.
There are a few elements that make Krill a better choice for Omega 3 fatty acids than fish oil, which usually comes from sardines, anchovies and mackerel. Krill is a phospholipid, which is a type of fat bound to phosphorus. As every cell membrane in our body is also made of phospholipids, krill oil gets absorbed significantly better than fish oil. Fish oil must go through a phosphorolation process in the liver before our cells can absorb it. Krill also contains nutrients like choline and astaxanthin that are not found in fish oil. Choline is a B vitamin that plays a vital role in nerve communication, which is essential for the eyes and brain to exchange information. Choline becomes acetyl choline, a brain chemical that plays a critical role in the activation of nerve and muscle cells. Our nerves cannot communicate, and we cannot move the six major muscles of the eye without acetyl choline. Astaxanthin is by far the most powerful carotenoid antioxidant when it comes to free radical scavenging: it is 65 times more powerful than vitamin C, 54 times more powerful than beta-carotene, and 14 times more powerful than vitamin E. Astaxanthin is far more effective than other carotenoids at "singlet oxygen quenching," which is how antioxidants protect against oxidation. Oxidation is a damaging process similar to rusting that significantly interferes with the healthy functioning of cells and tissues. Sunlight and UBV rays do a lot of oxidative damage that the eyes need to be protected from. Astaxanthin is 550 times more powerful than vitamin E and 11 times more powerful than beta-carotene at neutralizing this singlet oxygen. Astaxanthin is a potent UVB absorber, it reduces DNA damage and is a very powerful natural inflammation regulator, which means it protects against the three most damaging aspects of oxidation from free radicals. Astaxanthin crosses the blood-brain barrier AND the blood-retinal barrier (beta-carotene and lycopene do not), which has huge implications for the health of your eyes.
Krill also contains the Omega 3 fatty acids EPA and DHA. These amazing fats are essential for keeping the eyes moist and for the health of the tissues of the eye. DHA plays an incredibly important role in nerve communication between the eyes and the brain. The grey matter of the brain contains a significant amount of DHA. DHA is also found in very high concentrations in the retina and is so critical to retinal functioning that the retina is even able to recycle DHA when intake is low.11 DHA has important functions in the recreation of rhodopsin, a visual pigment that allows us to see in low light and at night. Rhodopsin also helps the eye adapt to rapid changes in light. Rhodopsin is destroyed by exposure to very bright light and is vital to the system that converts light hitting the retina to visual images in the brain. Rhodopsin allows us to see, and it dependent on DHA. 12 EPA plays a very important role in regulating inflammation throughout the body, and can halt the cycle of damage and inflammation caused by oxidative damage and poor diet. Omega 3 fats like krill oil also plays an important role in clearing and preventing plaque buildup that clogs arteries. By supporting the integrity of the vascular system and healthy circulation, these essential fatty acids keep oxygen, nutrients and a healthy blood supply flowing to the eyes and the brain (and the rest of the body as well).
A classic herb for the eyes, bilberries are an English fruit similar to blueberries but they have that beautiful dark purple-blue color not just in the skin, but all the way through. This makes them are a great source of anthocyanadins, an antioxidant that is very protective of our vision. Anthocyanadins support the structure of blood vessels, which supports healthy eye pressure and circulation to the eyes and the brain. Bilberry can be of great help to those with glaucoma.13 They have also been shown to act as a "sunscreen", protecting cells from high-light damage by absorbing blue-green and ultraviolet light, which protects the tissues from the stress of very bright light . Bilberries, through this powerful antioxidant, also help to combat inflammation and protect the nerves of the eye, against oxidative damage. Bilberries can even help people with myopia, or nearsightedness. When you are nearsighted, the curvature of their eyeball is off and you can only see things clearly when they're up close. Bilberry seems to help people focus better on things at a distance.14
The eyes require a many different nutrients for healthy, normal function. Good nutrition and a strong supplement program can make a world of difference in the health of your eyes. Your eyes can also be a strong indicator of when something is going wrong in the body. Nourish your eyes to support, maintain and even improve nerve communication, clear, sharp vision day or night, healthy circulation and normal eye pressure now and for the rest of your life. The rest of your body will also reap the benefits. Most people are willing to accept that poor vision and eye diseases are just something that will happen and get worse the older we get. Take a proactive stance and incorporate a few more colorful fruits and vegetables into your diet and a few key supplements that will support optimal vision. It’s a beautiful world, make sure you see it well now and for the rest of your days!
5. Institute of Medicine, Food and Nutrition Board. Beta-carotene and other carotenoids. Dietary reference intakes for vitamin C, vitamin E, selenium, and carotenoids. Washington, D.C.: National Academy Press; 2000:325-400
6. Mozaffarieh, Maneli, Stefan Sacu, and Andreas Wedrich. "The role of the carotenoids, lutein and zeaxanthin, in protecting against age-related macular degeneration: a review based on controversial evidence." Nutr J 2.1 (2003): 20.
7. Johanna M. Seddon et al, 1994, Journal of American Medical Association 272:1413-20.
8. Chiu, C. J. and A. Taylor . "Nutritional antioxidants and age-related cataract and maculopathy." Experimental eye research (2007) 84(2): 229-45
9. Radomska-Leoeniewskai D.M, Skopinskii, P, N-acetylcysteine as an anti-oxidant and anti-inflammatory drug and its some clinical applications, Centr Eur J Immunol 2012; 37 (1): 57-66)
10. Jain AK, Lim G, Langford M, Jain SK: Effect of high glucose levels on protein oxidation in cultured lens cells, and in crystalline and albumin solution and its inhibition by vitamin B6 and N-acetylcysteine: its possible relevance to cataract formation in diabetes. Free Radic Biol Med 2002; 33: 1615-1621.
11. Jeffrey BG, Weisingerb HS, Neuringer M, Mitcheli DC. The role of docosahexaenoic acid in retinal function. Lipids. 2001;36(9):859-871.
12. Stillwell W, Wassall SR. Docosahexaenoic acid: membrane properties of a unique fatty acid. Chem Phys Lipids. 2003;126(1):1-27
13. Shim SH, Kim JM, Choi CY, Kim CY, Park KH., Ginkgo biloba extract and bilberry anthocyanins improve visual function in patients with normal tension glaucoma.; J Med Food. 2012 Sep;15(9):818-23.
14. Kamiya K, Kobashi H, Fujiwara K, Ando W, Shimizu KJ Ocul Pharmacol Ther. Effect of fermented bilberry extracts on visual outcomes in eyes with myopia: a prospective, randomized, placebo-controlled study, J Ocul Pharmacol Ther. 2013 Apr;29(3):356-9