Thursday, May 15, 2008

Vision Care: Vitamin A for Your Eyes

Photograph of Cod Liver Oil capsules.Image via WikipediaDocumentation of vitamin A's benefits to the eyes goes back a long way. Ancient Egyptians ate liver to improve their vision, especially at night. Now we know that liver is one of the richest sources of vitamin A, which is essential for eye health.

Vitamin A is important for bone growth and helps maintain a healthy immune system. It preserves the integrity of the skin and mucous membranes, and is vital for a healthy reproductive system and cell division. Vitamin A is probably best known, though, for its role in eye health. Vitamin A in the diet has been linked to preventing cataracts, and may help prevent macular degeneration, the leading cause of blindness in the world.

Vitamin A deficiency may cause visual fatigue, dry eyes and sensitivity to light. Without sufficient vitamin A, your eyes recover very slowly when exposed to flashes of bright light at night and you may have difficulty seeing in dim light. Unless the vitamin A deficiency is corrected, your cornea can become damaged.

Fortunately, it’s easy to meet your daily vitamin A requirement. Cod liver oil, beef or chicken liver, whole milk and whole eggs all are excellent sources; as are carrots, pumpkin, mango, sweet potatoes, papaya and melon. Eating fresh foods is best, because heating, cooking or canning destroys vitamin A. If you don't want to eat foods that are rich in vitamin A in their raw forms, you can take a nutritional supplement. Because vitamin A is a fat-soluble vitamin (that is, the body can absorb it only with the help of fat in the diet), it’s best to take vitamin A after a meal.

Some people are particularly at risk of vitamin A deficiency, such as those with cystic fibrosis or pancreatic disorders, or if you’ve had stomach surgery or damage to the intestinal lining after diarrhea. These all cause your ability to absorb vitamin A to be adversely affected.

Vegetarians who do not consume eggs or dairy foods usually have a greater need for vitamin A supplementation, as do people who smoke or drink alcohol -- tobacco use prevents your body from absorbing vitamin A, and drinking alcoholic beverages depletes the vitamin A already stored in your body.

Remember, however, that “more” is not always “better.” To be safe, follow the NIH Institute of Medicine Daily Tolerable Upper Levels for intake of vitamin supplements to help prevent the risk of toxicity:

Recommended Dietary Allowances (RDAs) for vitamin A

(mcg RAE)
(mcg RAE)
(mcg RAE)
(mcg RAE)
(mcg RAE)
(1,000 IU)

(1,320 IU)

(2,000 IU)

(3,000 IU)
(2,310 IU)
(2,500 IU)
(4,000 IU)
(3,000 IU)
(2,310 IU)
(2,565 IU)
(4,300 IU)

Excerpt from the NIH Vitamin A and Carotenoids Fact Sheet:
RDAs for vitamin A are listed as micrograms (mcg) of Retinol Activity Equivalents (RAE) to account for the different biological activities of retinol and provitamin A carotenoids. This table also lists RDAs for vitamin A in International Units (IU), which are used on food and supplement labels (1 RAE = 3.3 IU)

NOTE: The information in this article about vitamin A is not meant to take the place of professional medical advice. Check with your doctor before making decisions on any vision care supplement.
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Monday, May 12, 2008

Vision Care: How to Keep Your Eyes Healthy for Life

Fresh Swiss chardImage via WikipediResearch has indicated that people who have ample antioxidants in their blood have reduced risk of developing macular degeneration and cataracts. What are antioxidants? They're found in fruits and vegetables and they "mop up" unstable oxygen molecules in your blood known as free radicals, which prevents cellular damage. They're good for your general health, but one group of antioxidants in particular -- carotenoids -- is especially good for your eyes. In fact, some people have even use the term "eye vitamins" for these beneficial nutrients.

The best sources of carotenoids are brightly colored fruits and vegetables, and carrots are especially high in the carotenoid called beta-carotene. Beta-carotene can be converted into vitamin A, which helps you have healthy night vision. If you lack vitamin A, it takes much longer for your eyes to adjust to a change in light.

Recent research suggests that the carotenoids lutein and zeaxanthin, which are found in dark green, leafy vegetables, are even more powerful than beta-carotene for eye health because they are the only carotenoids that concentrate specifically in the eye tissues. Spinach, kale, broccoli, Swiss chard and collard greens contain such high levels of lutein and zeaxanthin that adding these vegetables to your diet can reduce the risk of developing cataracts by up to 23 percent, and cut the risk of developing macular degeneration in half.

Cranberries are also an excellent source of another type of powerful antioxidant, bioflavonoids, which help protect the lens of the eye as well as strengthen the collagen-rich structures of the eye, such as the cornea and capillaries. Bioflavonoids are also found in blueberries, grapes (all but the green variety), citrus fruits and bilberries. Although bilberries may not be on your typical shopping list, they have an exceptionally high bioflavonoid content. In fact, during World War II, British fighter pilots ate bilberries before going on nightly bombing raids because their night vision improved as a result. That's why bilberry is often found in supplements for eye health.

Some of the nutrients in cold water fish, such as salmon, mackerel and cod, can also be of benefit to your eyes. They're rich in omega-3 fatty acids, which can help lower eye pressure and promote circulation of blood to the eye. Fish also contains taurine, which helps regenerate retinal tissues, and helps protect the eyes from ultraviolet radiation.

Of course, nothing replaces a well-balanced diet, but you might want to consider taking supplements to help ensure you’re giving your eyes all the nutrition they need. Supplements that contain lutein and zeaxanthin are readily available; just be sure to choose a one that contains an effective level of lutein (about 3-6mg per day). And antioxidant vitamins such as C an E, as well as alpha lipoic acid, may be especially useful for protecting delicate eye structures from damage and promoting the repair process. A major antioxidant enzyme, glutathione, may be effective in preventing cataract formation, and is helpful in possibly altering free radical damage.

Just remember: Eating right and taking supplements won’t help much if you compromise your eye health by spending too much time in the sun or smoking. It's commonly known that sun bathers and smokers have to worry about preventative skin care. But did you know they also have an increased risk of developing cataracts and impaired vision? That doesn't have to be a problem for you though. Studies show that stopping smoking and limiting sun exposure can have significant benefits at any age.

You might also be interested in this other vision care article: Bilberry for Your Eyes

NOTE: The information in this article is not meant to take the place of professional medical advice. Check with your doctor before making decisions on any vision care supplement.

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Friday, May 9, 2008

Vision Care: Protect Your Eyesight!

Bugs Bunny and a gremlin in Falling Hare (1943)

You might not know it, but your eyes reflect your overall health. Because they're so sensitive, trouble with the eyes may indicate general health problems. High blood pressure, for example, causes blood vessels in the eye to narrow, constricting blood flow that often leads to glaucoma; macular degeneration can be traced in part to nutritional deficiencies; and adult onset diabetes sometimes results in retinal damage and cataracts. Early detection, along with regular eye exams and attention to maintaining healthy eyes, helps to control and often prevent vision loss due to health problems.

Our eyes are much like the rest of the body -- exercise, good nutrition and a healthy lifestyle all help to ensure eye health. Although the thought of eye exercises might seem a little strange, vision improvement exercises can make a definite difference in long-term eye health.

And we can't ignore diet's role when it comes to the eyes. In a perfect world, our diets would include plenty of protein, natural calcium and other minerals, vegetables, carbohydrates and fat. Unfortunately, that's usually not the case. So what should you do? Reducing saturated fat, sugar and artificial additives can lower your risk for vascular disease, which in turn improves circulation to the eyes. And eating more bright-colored fruits and vegetables, such as oranges and carrots, enhances absorption of vitamin A. After all, has Bugs Bunny ever worn glasses?

But if you've had your fill of veggies and citrus, or if you just want to make sure your body is getting enough of the nutrients it needs, supplementation may be the answer. Antioxidants such as vitamins A, C and E and lutein support healthy eyes and protect your lenses from ultraviolet damage. Lipoic acid is highly effective against a wide variety of oxidants, and also has the ability to regenerate vitamins C and E.

Certain herbs are beneficial, too. Bilberry has been shown to improve night vision and help adaptation to bright light. Recent research suggests that it also enhances capillary integrity. Eyebright has a long history of use in maintaining healthy eyes. It helps improve tear quality, as well as improving the health of the lens, cornea and retina.

Eyesight is arguably the most important of our five senses. Fortunately, you can do your part to protect your eyesight with simple lifestyle adjustments and making sure your body is properly nourished.

NOTE: The information in this article is not meant to take the place of professional medical advice. Check with your doctor before making decisions on any vision care supplement.

Wednesday, May 7, 2008

Vision Care: Lutein for Eye Health

Popeye, the cartoon character with a yen for spinach, ate that dark-green leafy vegetable whenever he wanted to increase his strength. Real-life scientists know that spinach -- along with a number of other fruits and vegetables -- is a rich source of lutein. And while it may not make you a strongman (or woman), lutein has many health benefits, particularly for your eyes.

Lutein (pronounced LOO-teen) is a carotenoid (a yellow to red pigment-producing compound) that acts as an antioxidant. Found in vegetables and fruits, antioxidants guard your cells against the damaging effects of free radicals. And while all antioxidants help maintain cells and tissues for overall good health, lutein is especially important for eye health.

Lutein accumulates in the eye in the macular region of the retina, where it acts as internal sunglasses, preserving eye integrity by filtering out the sun’s ultraviolet rays. If the macula becomes damaged by oxidation, often caused by years of exposure to sunlight, it can result in a condition known as macular degeneration, a leading cause of irreversible blindness in the elderly. According to the National Eye Institute at the National Institutes of Health, studies suggest a link between lutein and decreased risk of eye disease.

Adults who eat lutein-rich foods -- at least 6 mg of lutein per day -- have a significantly reduced risk (as much as 43 percent) of developing macular degeneration. That’s because in addition to guarding against free-radical damage, lutein helps build macular pigment density, which is related to clarity of the lens of the eye. Researchers at Indiana University School of Medicine and Ophthalmology note that lutein can play an important role in reducing formation of cataracts, which also result from oxidation of the eye’s lens.

But lutein is not just for the elderly. Most eye disease develops over a number of years, so by the time seniors are diagnosed with AMD or cataracts, the disease may have been developing for 20 years or more. Additionally, lutein may help reduce glare and prevent eye fatigue in persons whose jobs are performed primarily in bright sunlight, such as lifeguards, airline pilots or truck drivers. Those who work in front of a computer screen also will benefit from lutein.

As another health perk, researchers are looking at lutein’s role in reducing risk of certain types of cancer, noting that consumption of lutein-rich foods may help prevent the development of the disease process in those with no history of the disease. And lutein may play an important role in reducing risk of heart disease because of its ability to fight free radicals.

So how can you get this carotenoid antioxidant? The highest concentration of lutein is found in spinach, kale, collard greens, mustard greens and other leafy green vegetables; broccoli, Brussels sprouts, and in some fruits, such as oranges and cantaloupe. Lutein also is present in egg yolk.

Unfortunately, many people don’t eat enough of these foods to get an adequate amount of lutein. If collard greens and kale aren’t on your daily menu, or if you’re unlikely to dig in to a large spinach salad or an egg-yolk omelet every day, it’s a good idea to take a nutritional supplement that contains lutein.

NOTE: The information in this article is not meant to take the place of professional medical advice. Check with your doctor before making decisions on any vision care supplement.

Monday, May 5, 2008

Vision Care: Preventing Glaucoma

Although we make take it for granted, few things are more precious to us than our sight. Imagine, then, that one day you realize you can’t see objects out of the corner of your eye. You may chalk it up to eye strain or aging, but then -- suddenly -- you find you have no side vision at all; it’s as if you’re looking through a tunnel. Over time, if you don’t seek treatment, even this narrowed vision will disappear into blindness.

What is glaucoma?
Glaucoma, a progressive eye disease that damages the optic nerve, has resulted in blindness for an estimated 120,000 Americans. It’s been called the “silent thief” because most people with undiagnosed glaucoma have no symptoms until they begin to notice they’re losing their peripheral vision. By that time, the optic nerve is already damaged. And once gone, areas of lost vision cannot be restored.

Your eyes maintain their shape due to inside (intra-ocular) pressure. Glaucoma causes this intra-ocular pressure (IOP) to increase above values considered normal. (Normal IOP is different for every individual.) Over time, increased IOP compresses the nerve at the back of the eye, resulting in a slow loss of vision (“open-angle glaucoma”) without noticeable symptoms. The more severe form, known as “closed-angle glaucoma,” has extreme symptoms -- sudden eye pain, nausea, headache, and rapid vision loss -- and is an ocular emergency. Permanent loss of vision may occur in as few as three days.

Ninety percent of glaucoma cases, however, are open-angle glaucoma -- the less severe and more easily treated form of the disease. Although anyone can get glaucoma, some people are at higher risk than others. They include:
  • Anyone over age 60 (or those older than 45 who have not had regular eye examinations)
  • People with a family history of glaucoma
  • Afro-Americans over age 40
  • Diabetics
  • People with severe myopia (near-sightedness)
What can be done about glaucoma?
Studies have shown that early detection and treatment of glaucoma -- before it causes major vision loss -- is the best way to control it. See your eye-care professional at least every two years (more often if you are high-risk) for a complete eye exam, including IOP checks. IOP checks are simple, quick and painless procedures that measure the fluid pressure inside your eyes. They include a “puff test,” which measures the resistance of your eye to a puff of air blown against its surface; and use of a tonometer, an instrument that is lightly touched to the surface of your eye for a more accurate measurement. (Don’t worry -- prior to this test, the surface of your eye is numbed with eye drops, and the procedure itself takes just a moment.)

Additional tests may also be performed. You may be given a visual field test, which measures your side (peripheral) vision and can detect even minute losses of vision. For this test you will be asked to focus your eyes straight ahead at a central point, and then to say when you see a spot of light appear at the side. Your eye care professional may also check for signs of optic nerve damage by placing drops in your eyes to dilate (widen) your pupils so he can get a better view of the optic nerve.

Treatment of glaucoma depends on the type and severity of the disease. Closed-angle glaucoma usually requires laser treatment to make a new opening in the iris, along with medication to help clear the angle. Conventional surgery is sometimes necessary if laser surgery is unsuccessful. The more common open-angle glaucoma treatment usually begins with prescription eye drops or oral medication to lower intra-ocular pressure. Complementary treatments for glaucoma may also be suggested, and although these should not be used in place of your prescribed treatment, they may help control the disease. Vitamin B12, for example, has been shown to help prevent loss of field vision, and vitamin C may lower intra-ocular pressure. Vitamin E is helpful in removing particles from the lens of the eye, and can aid in the protection of the tissue of the eye. Important minerals for eye health are zinc, selenium and magnesium.

Of course, the ideal way to ensure you get an adequate supply of these essential vitamins and minerals is to eat a balanced diet, but if you’re like most Americans, you don’t always eat as you should, so take a nutritional supplement. Certain lifestyle changes will also help. Studies indicate a brisk daily walking program may reduce intra-ocular pressure as much as pressure-reducing eye drops. And regular exercise not only helps reduce eye pressure on its own, it can have a positive impact on glaucoma risk factors such as diabetes.

Right now, there is no way to prevent glaucoma, nor is there a definite cause of the disease. It’s a lifelong illness, but proper treatment can prevent loss of vision. Get regular eye exams as part of a vision care plan to safeguard your precious sight. And if you have symptoms of diabetes, make sure to let your eye doctor know. He may want to check your eyes more frequently.

For the latest glaucoma vision care recommendations, visit the Glaucoma Research Foundation.

NOTE: The information in this article is not meant to take the place of professional medical advice. Check with your doctor before making decisions on any vision care supplement.

Vision Care: Bilberry for the Eyes

Bilberry fruit

Bilberry could change the way you look at vision care.

During World War II, British Royal Air Force pilots ate bilberry jam before flying their evening bombing raids; they’d noticed that their night vision was sharper than usual whenever they ate the jam before starting their nighttime missions.

Although bilberry has been used as a medicinal herb since the 16th century, it was after the RAF pilots’ discovery that this plant got its modern reputation as a link to eye health. Recent clinical research confirms that ingesting bilberries improves visual acuity in healthy people, and can help improve vision in those with certain eye diseases, such glaucoma, cataracts, and age-related macular degeneration (AMD).

This cousin to the blueberry (also known as huckleberry in the US and whortleberry in England) has a history of treating a variety of health problems. Herbal medicine practitioners have long recommended bilberry to treat scurvy, urinary tract infections, stomach and digestive problems, and vascular and blood disorders. Dried bilberry fruit has been used as a remedy for nausea, indigestion and diarrhea; and to treat sore throat, sinusitis and kidney stones.

Bilberry's "secret ingredients"
How can this berry do so much? The “secret ingredients” in bilberry are compounds called anthocyanosides, which strengthen blood vessels and improve circulation, and can also be found in many Chinese herbal remedies. Anthocyanosides are natural antioxidants that also help lower blood pressure and reduce the stickiness of blood platelets, which helps prevent formation of blood clots. Bilberry leaves are a good source of chromium, which may help control blood sugar levels in people with diabetes. Bilberry also is high in tannin, which helps control and reduce the intestinal inflammation that can cause diarrhea. And bilberry contains vitamins A and C, boosting its antioxidant power and helping to prevent free radical damage to the eyes. These vitamins and the anthocyanoside compounds make bilberry a powerhouse of eye protection.

Studies indicate bilberry may help prevent glaucoma, which is characterized by increased intra-ocular pressure, by stabilizing and preventing the destruction of collagen in eye tissue. Because bilberry improves the strength and integrity of collagen, it also may help prevent cataracts, another eye disease that results, in part, when the collagen matrix of the lens becomes weak and fragile. And the anthocyanoside compounds in bilberry have been shown to help prevent macular degeneration, a devastating eye condition that eventually leads to blindness, by increasing blood flow to the macula of the retina. Even if you’re fortunate enough to have healthy eyes, bilberry can help provide protection from eyestrain or fatigue, and (as with the RAF pilots in the ’40s) improve your night vision.

What’s the best way to get your bilberry? Some people enjoy fresh bilberries, or bilberry tea made from the dried berry or its leaves. But a no-fuss option is to take nutritional supplements with standardized bilberry extract. Not only is it more convenient to take a supplement than to hunt for fresh bilberries, supplements provide increased benefits -- you’d need a large quantity of berries or tea to get the same vision care benefits provided by the highly concentrated bilberry extract.

NOTE: The information in this article is not meant to take the place of professional medical advice. Check with your doctor before making decisions on any vision care supplement.