11 September, 2012

All About "Cholesterol"

What Is Cholesterol?

We may associate cholesterol with fatty foods, but most of the waxy substance is made by our own bodies. The liver produces 75% of the cholesterol that circulates in our blood. The other 25% comes from food. At normal levels, cholesterol actually plays an important role in helping cells do their jobs. But cholesterol levels are precariously high in more than 100 million Americans.

Symptoms of High Cholesterol

High cholesterol does not cause any symptoms. But it does cause damage deep within the body. Over time, too much cholesterol may lead to a buildup of plaque inside the arteries. Known as atherosclerosis, this condition narrows the space available for blood flow and can trigger heart disease. The good news is high cholesterol is simple to detect, and there are many ways to bring it down.

Cholesterol Testing

People older than 20 should have their cholesterol levels checked at least once every five years. This is done with a simple blood test known as a fasting lipoprotein profile. It measures the different forms of cholesterol that are circulating in your blood after you avoid eating for nine to 12 hours. The results show your levels of "bad" cholesterol, "good" cholesterol, and triglycerides.

'Bad' Cholesterol

Most of the cholesterol in the blood is carried by proteins called low density lipoproteins or LDL. This is known as the bad cholesterol because it combines with other substances to clog the arteries. A diet high in saturated fats and trans fats tends to raise the level of LDL cholesterol. For most people, an LDL score below 100 is healthy, but people with heart disease may need to aim even lower.

'Good' Cholesterol

Up to a third of blood cholesterol is carried by high-density lipoproteins or HDL. This is called good cholesterol because it helps remove bad cholesterol, preventing it from building up inside the arteries. The higher the level of HDL cholesterol, the better. People with too little are more likely to develop heart disease. Eating healthy fats, such as olive oil, may help boost HDL cholesterol.


The body converts excess calories, sugar, and alcohol into triglycerides, a type of fat that is carried in the blood and stored in fat cells throughout the body. People who are overweight, inactive, smokers, or heavy drinkers tend to have high triglycerides, as do those who eat a very high-carb diet. A triglycerides score of 150 or higher puts you at risk for metabolic syndrome, which is linked to heart disease and diabetes.

Total Cholesterol

Total cholesterol measures the combination of LDL, HDL, and VLDL (very low density lipoprotein) in your bloodstream. VLDL is a precursor of LDL, the bad cholesterol. A total cholesterol score of under 200 is considered healthy in most cases. People who score in the "high" range have an increased risk of developing heart disease compared to those who score below 200.

Cholesterol Ratio

To calculate your cholesterol ratio, divide your total cholesterol by your HDL cholesterol. For example, a total score of 200 divided by an HDL score of 50 equals a cholesterol ratio of 4 to 1. Doctors recommend maintaining a ratio of 4 to 1 or lower. The smaller the ratio, the better. While this figure is useful in estimating heart disease risk, it's not as important in guiding treatment. Doctors look at total cholesterol, HDL cholesterol, and LDL cholesterol to determine treatment.

Cholesterol in Food

Cholesterol-rich foods, like eggs, shrimp, and lobster are no longer completely forbidden. Research shows that the cholesterol we eat has only a small effect on blood cholesterol levels for most people. A few people are "responders," whose blood levels spike up after eating eggs. But for most, saturated fat and trans fats are bigger concerns. Daily cholesterol limits are 300 mg for healthy people and 200 mg for those at higher risk. One egg has 186 mg of cholesterol.

Cholesterol and Family History

Cholesterol comes from two sources -- the body and food -- and either one can contribute to high cholesterol. Some people inherit genes that trigger too much cholesterol production. For others, diet is the main culprit. Saturated fat and cholesterol occur in animal-based foods, including meat, eggs, and dairy products made with milk. In many cases, high cholesterol stems from a combination of diet and genetics.

What Boosts Your Risk?

Several factors can make you more likely to develop high cholesterol:
  • A diet high in saturated fats and cholesterol
  • A family history of high cholesterol
  • Being overweight or obese
  • Getting older

Cholesterol and Gender

Until menopause, women typically have lower total cholesterol levels than men of the same age. They also have higher levels of HDL cholesterol, the good kind. One reason is estrogen: The female sex hormone raises the level of HDL cholesterol. Estrogen production peaks during the childbearing years and drops off during menopause. After age 55, a woman's risk of developing high cholesterol begins to climb.

Cholesterol and Children

There's evidence that cholesterol can begin clogging the arteries during childhood, leading to atherosclerosis and heart disease later in life. The American Heart Association recommends kids and teenagers with high cholesterol take steps to bring it down. Ideally, total cholesterol should be below 170 in people ages 2 to 19.

Why High Cholesterol Matters

High cholesterol is one of the major risk factors for coronary artery disease, heart attacks, and strokes. It also appears to boost the risk of Alzheimer's disease. As we saw earlier, high cholesterol leads to a buildup of plaque that narrows the arteries. This is dangerous because it can restrict blood flow. If the blood supply to a part of the heart or brain is completely cut off, the result is a heart attack or stroke.

Cholesterol Buster: Eat More Fiber

Diet changes offer a powerful way to fight high cholesterol. If you've ever wondered why some cereals claim to be heart-healthy, it's the fiber. The soluble fiber found in many foods helps reduce LDL, the bad cholesterol. Good sources of soluble fiber include whole-grain breads and cereals, oatmeal, fruits, dried fruits, vegetables, and legumes such as kidney beans.

Cholesterol Buster: Know Your Fats

No more than 35% of your daily calories should come from fat. But not all fats are equal. Saturated fats -- from animal products and tropical oils -- raise LDL cholesterol. Trans fats carry a double-whammy, boosting bad cholesterol, while lowering the good kind. These two bad fats are found in many baked goods, fried foods (doughnuts, fries, chips), stick margarine, and cookies. Unsaturated fats may lower LDL when combined with other healthy diet changes. They're found in avocados, olive oil, and peanut oil. 

Cholesterol Buster: Smart Protein

Meat and full-fat milk offer plenty of protein, but they are also major sources of cholesterol. You may be able to reduce LDL cholesterol by switching to soy protein, such as tofu, at some meals. Fish is another great choice. It's rich in omega-3 fatty acids, which can improve cholesterol levels. The American Heart Association recommends eating fish at least twice a week.

Cholesterol Buster: Low-Carb Diet

There's growing evidence that low-carb diets may be better than low-fat diets for improving cholesterol levels. In a two-year study funded by the National Institutes of Health, people who followed a low-carb plan had significantly better HDL (good cholesterol) levels than those who followed a low-fat plan.

 Cholesterol Buster: Lose Weight

If you're overweight, talk to your doctor about beginning a weight loss program. Losing weight can help you reduce your levels of triglycerides, LDL, and total cholesterol. Shedding even a few pounds can also boost your good cholesterol level -- it tends to go up one point for every 6 pounds you lose.

Cholesterol Buster: Quit Smoking

Giving up tobacco is tough, but here's one more reason to try. When you stop smoking, your good cholesterol is likely to improve by as much as 10%. You may be more successful if you combine several smoking cessation strategies. Talk to your doctor about which options are best for you.

 Cholesterol Buster: Exercise

If you're healthy but not very active, starting an aerobic exercise program could increase your good cholesterol by 5% in the first two months. Regular exercise also lowers bad cholesterol. Choose an activity that boosts your heart rate, such as running, swimming, or walking briskly, and aim for at least 30 minutes on most days of the week. It doesn't have to be 30 continuous minutes; two 15-minute walks works just as well.

Treatment: Medications

If high cholesterol runs in your family, diet and exercise may not be enough to get your numbers where you want them. In that case, medication can give your cholesterol levels an extra nudge. Statins are usually the first choice. They block the production of cholesterol in the liver. Other options include cholesterol absorption inhibitors, bile acid resins, and fibrates. Your doctor may recommend a combination of these medications.

Treatment: Supplements

Certain dietary supplements may also improve cholesterol levels. These include flaxseed oil, fish oil, and plant sterols, such as beta-sitosterol. Prescription niacin, a B-complex vitamin, has been found to raise good cholesterol while reducing bad cholesterol. Niacin found in ordinary supplements should not be used to lower cholesterol.

Herbal Remedies

Some studies suggest garlic can knock a few percentage points off total cholesterol. But garlic pills can have side effects and may interact with medications. Other herbs that may reduce cholesterol include:
  • Fenugreek seeds
  • Artichoke leaf extract
  • Yarrow
  • Holy basil

How Low Should You Go?

Many people are able to lower cholesterol levels through a combination of medication and lifestyle changes. But how low is low enough? For people with diabetes or a high risk of developing heart disease, an LDL score of less than 100 is desirable. If you already have heart disease or coronary artery disease, some doctors recommend reducing LDL to 70 or lower.

Can the Damage Be Undone?

It takes years for high cholesterol to clog the arteries with plaque. But there is evidence that atherosclerosis can be reversed, at least to some degree. Dean Ornish, MD, has published several studies showing that a low-fat vegetarian diet, stress management, and moderate exercise can chip away at the build-up inside the coronary arteries. Other research supports the idea that big drops in cholesterol can somewhat help open clogged arteries.

21 Juli, 2012

Eye Problems

Warning Signs of Eye Trouble
Blurry vision, spots, glare at night -- these are common eye complaints that can be harmless annoyances or an early sign of disease. In the slides ahead, we explore several eye problems and offer two quick eye tests. You'll see the world through eyes that have floaters, cataracts, myopia, and glaucoma. Be sure to see an eye doctor promptly for any concerns.

Color Blindness Test
Which number do you see in the far left? If it's "3," you probably have normal color vision. If it's a "5," you may be  colorblind. This view is simulated in the center panel and represents a mild color vision deficiency. About 10% of men are born colorblind, but few women. Complete color blindness (very rare) is simulated at right. No number is visible. Tinted glasses may help the colorblind see better.

Nearsightedness (Myopia)
About 33% of Americans (ages 12-54) have a blurry view of distant objects, called myopia, up from about 25% in the early 1970s. Risk factors include:
  • Family history (one or both parents)
  • Lots of prolonged, close-up reading
Trouble with driving, sports, or seeing a blackboard or the TV may ensue. Symptoms include headaches, squinting, and fatigue. Myopia can be treated with glasses, contacts, or surgery in some cases.

Farsightedness (Hyperopia)
Most of us are born with mild farsightedness, but normal growth in childhood often corrects the problem. When it persists, you may see distant objects well, but books, knitting, and other close objects are a blur. Hyperopia runs in families. Symptoms include trouble with reading, blurry vision at night, eyestrain, and headaches. It can be treated with glasses, contacts, or surgery in some cases.

Just like gray hair or  wrinkles, trouble reading fine print  is a sign of aging. Called presbyopia -- or "old eye" in Greek -- symptoms  appear in the 40s. The eyes' lenses  become less flexible and can't change shape to focus on objects at reading distance. The solution: reading glasses or bifocals, which correct both near and distance vision. If you wear contacts, ask your eye doctor about contacts made for people with presbyopia.

Nearsightedness: What Happens
Typically, an eyeball that's too long causes myopia. But an abnormally shaped cornea or lens can also be to blame. Light rays focus just in front of the retina, instead of directly on it. This sensitive membrane lines the back of the eye (seen in yellow) and sends signals to the brain through the optic nerve. Nearsightedness often develops in school-age children and teens, who need to change glasses or contacts frequently as they grow. It usually stabilizes by the early 20s.

Farsightedness: What Happens
In hyperopia, the cause is often an eyeball that is too short. Light rays focus behind the retina, causing close objects to be blurry. In severe cases of hyperopia, especially after the age of 40, distance vision can be blurred as well. An abnormal shape in the cornea or lens can also lead to farsightedness. Children with significant hyperopia are more likely to have crossed eyes (strabismus) and may have difficulty reading. That’s one of the reasons eye doctors recommend vision exams for young children.

Your vision may be out of focus at any distance with an astigmatism in one or both eyes. It occurs when the cornea, the clear “window” that covers the front of the eye, is misshapen. Light rays can be scattered in different points on the retina, rather than focusing on a single point. Glasses or contact lenses correct the problem, and surgery may be another option. Along with blurred vision, symptoms may include headaches, fatigue, and eye strain.

Refractive Eye Surgery
Do you dream of seeing clearly without glasses? Surgery to reshape the cornea can correct nearsightedness, farsightedness, or astigmatism with a success rate of better than 90%. People with severe dry eye, thin or abnormally shaped corneas, or severe vision problems may not be good candidates. Possible side effects include glare or sensitivity to light.

Glaucoma: View
You can't feel it, but deterioration of the optic nerve oftentimes with elevated eye  pressure can silently steal your sight, a condition called glaucoma.  There may be no symptoms until central vision is lost (following gradual loss of peripheral vision), so regular eye exams are critical to find it early. Those at higher risk include:
  • African-Americans over 40
  • Anyone over 60, especially Mexican-Americans
  • People with a family history
Fortunately, glaucoma can be treated with medications or surgery. Regular eye exams every 1-2 years after age 40 can catch it early.

Glaucoma: What Happens
In the most common form of glaucoma, increased eye pressure leads to optic nerve damage and loss of vision. The eye is filled with circulating fluid that nourishes its internal structures. Sometimes the balance between fluid creation and exit is abnormal. The buildup of fluid increases pressure and damages the optic nerve at the back -- the bundle of 1 million nerve fibers that carry information to the brain. Without treatment, glaucoma can cause total blindness.
The bright yellow circle shows an optic nerve head that is damaged by glaucoma. The dark central area is the macula, responsible for finely-detailed central vision.

Macular Degeneration: View
Age-related macular degeneration (AMD) damages, then destroys, the eye's finely-detailed central vision, making it difficult to read or drive. Symptoms can include a central blurry spot or straight lines that appear wavy. Finding and treating AMD promptly can help slow vision loss. Being over 60, smoking, high blood pressure, obesity, and a family history of AMD increase your risk.

Macular Degeneration: What Happens
In AMD, the central part of the retina, called the macula, deteriorates. In the dry form, doctors often see yellow deposits called drusen in the macula. As dry AMD progresses, the macular tissue deteriorates, gradually shutting down the delivery of images to the brain. In the wet form, abnormal blood vessels grow. They leak blood and fluid (seen here), causing scarring and further damage to the macula. Both types lead to a central blind spot.

Macular Degeneration: Test
Cover one eye and stare at the center dot in this Amsler Grid, from a distance of 12 to 15 inches. (You can wear your reading glasses.) Do you see wavy, broken, or blurry lines? Are any areas distorted or missing? Repeat the procedure for your other eye. While no self-test can substitute for an eye exam, this grid is used to help detect early symptoms of AMD.

Macular Degeneration:Signs
As seen here, the Amsler Grid can look quite distorted to someone with significant macular degeneration and may include a central dark spot. Straight lines that appear wavy are also cause for concern, as they can be an early symptom of "wet" AMD, the more serious and fast-moving type of macular degeneration. Your eye care professional will want to evaluate you right away, starting with a thorough dilated eye exam.

Diabetic Retinopathy: View
Type 1 and type 2 diabetes can cause partial vision loss (seen here) and lead to blindness. The damage involves tiny blood vessels in the retina and can often be treated, but don't wait for symptoms. By the time they occur --  blurry vision, spots, shadows, or pain -- the disease may be severe. People with known diabetes need annual eye exams, sometimes even more often if diabetic eye changes have begun. The best prevention is keeping your blood sugar in check.

Diabetic Retinopathy: What Happens
When high blood sugar levels go unchecked, it can damage the tiny blood vessels that support the retina. These blood vessels can swell, break, and leak fluid.  In some cases, dozens of new, abnormal blood vessels grow, a condition called proliferative retinopathy. The abnormal vessels are very fragile and break open easily. These processes gradually damage the retina, causing blurred vision, blind spots, or blindness.  

Cataracts: View
Age is not kind to our eyes. By the time we're 80 years old, more than half of us will have had a cataract, or clouding of the lens. Vision gradually gets foggy and makes it hard to read, drive, and see at night.  Diabetes, smoking, or prolonged sunlight exposure may increase the risk. Surgery that replaces the clouded lens with an artificial lens is highly effective.

Cataracts: What Happens
In good health, the lens focuses light into a sharp, clear image on the retina, which captures the image like film in a camera. As we age, protein builds up in the lens, clouding it, and sending scattered rays of light to the retina, instead of one sharp clear image. The result can be blurred vision, changes in color vision, and glare, especially at night. Very advanced cataracts are visible to the naked eye -- the muddy-colored circle at the center of this picture.

Retinitis Pigmentosa
RP is an inherited disorder that often begins with night vision problems, followed by a gradual loss of side vision, developing into tunnel vision, and finally, in some cases, blindness. One in 4,000 American have RP. A promising study showed that high-dose vitamin A supplements can reduce vision loss. However, you should consult a health care expert before taking supplements because too much vitamin A can be toxic.

Retinitis Pigmentosa: What Happens
The light-sensitive tissue of the retina slowly deteriorates over many years in people with RP. As this tissue dies, it stops sending signals to the brain, and some vision is lost.  Eye exams show abnormal dark spots (pigments) sprinkled around the retina. Early cataracts can also occur, as well as a swelling of the retina called macular edema (the central orange mass seen here).

Floaters and Specks
Blurry spots or specks in your vision that move may be floaters -- debris in the eye's vitreous gel. They don't block vision and are more easily seen in bright light. Floaters are common and usually harmless. But if they appear or increase suddenly, or are accompanied by light flashes, you should see a doctor. Vision abnormalities that tend to be more serious include  persistent white or black spots and a sudden shadow or loss of peripheral vision. These require immediate evaluation.

Ambylopia (Lazy Eye)
During childhood, when vision is reduced in one eye, the brain sometimes favors the other eye. This condition, called ambylopia, may stem from a misalignment of the eyes (strabismus or crossed eyes) or poorer vision in one eye. A patch or drops that blur the vision in the "good" eye can prod the brain to use the other eye. If untreated during childhood, vision loss from amblyopia can be permanent.

Eye Care: Object in the Eye
Many nerve endings lurk just beneath the surface or your cornea, so a tiny speck can be surprisingly painful. Don't rub the eye, or you may cause serious damage. Gently flushing the eye with lukewarm water is often recommended. If it doesn't dislodge the foreign body, or you have any questions, call a medical provider who can remove the object and provide antibiotic drops to protect the cornea from infection.

Eye Care: Tears and Dry Eye
Tears are the lubrication for our eyes. When not enough flow, perhaps due to dry air, aging, or other health conditions, the eyes can become painful and irritated. For people with mild cases of dry eye, occasionally using eye drops labeled artificial tears may do the trick. Others with more pronounced and frequent dry eye symptoms may need other medications or a procedure to block the exit ducts.

Eye Care: Pinkeye
Pinkeye, or conjunctivitis, is an inflammation caused by a virus, bacteria, irritant, or allergy. Along with the telltale redness, you might have an itching or burning sensation and a discharge. If itching is the main symptom, the cause is likely to be allergy. Most cases of infectious pinkeye are viral, which don't require antibiotics. Bacterial conjunctivitis is typically treated with antibiotic eye drops. Bacterial and viral conjunctivitis are very contagious, so wash your hands frequently while you wait for it to clear up.

Eye Care: Stye
A stye is a tender red bump that looks like a pimple on or near the edge of the eyelid. It is just one type of infection of the eyelids (blepharitis). Styes usually heal in a week, but using a very warm, wet compress three to six times a day can speed the healing. Don’t wear contact lenses or eye makeup until it heals.

Eye Care: Allergies
Millions of Americans suffer from allergies -- and watery, itchy eyes. Pollen, grass, dust, weeds, and pet dander are common triggers. Reduce the allergens in your home with allergen impermeable covers on mattresses and pillows, thorough cleaning, and allergen filters in the furnace and air conditioner. Allergy eye drops, artificial tears, and antihistamines also may soothe the symptoms.

Eye Care: Regular Exams
Everyone needs regular eye exams. This is particularly important if you have risk factors or a family history of eye problems. Children need their vision checked at 6 months, 3 years, and before first grade. Adults should see an eye doctor at least every two years and annually after age 60. Beyond vision issues, the eyes can reveal underlying health problems, such as diabetes and high blood pressure, or serious disorders like stroke or brain tumor. Bulging eyes are a sign of thyroid disease, and a yellow tint of the whites of the eyes may indicate liver problems.

Tips to keep your eyes healthy :

Eye Protection: Sun

UV rays can damage your eyes, just as they do your skin. Regular overexposure to sun can cause cataracts 8-10 years early, and a single lengthy exposure can actually burn your corneas. The solution is sunglasses that block UV rays and a hat. People with light-colored eyes are likely to have a greater sensitivity to light. New or pronounced sensitivity to bright light can be a sign of a more serious eye condition.

Eye Protection: Everyday Hazards

Grease splatters from a pan, yard debris flies up from the lawn mower, cleaning solution splashes in a bucket. Some of the greatest hazards to the eyes are in the home. The American Academy of Ophthalmology recommends that every household have ANSI-approved protective eyewear. Even if an eye injury seems minor, go to the emergency room immediately to check it out.

Foods for Eye Health

Carrots really are good for your eyes. So are spinach, nuts, oranges, beef, fish, whole grains, and many other foods in a healthy diet. Look for foods with antioxidants such as omega-3 fatty acids; vitamins C, E, and beta-carotene; as well as zinc, lutein, and zeaxanthin. Research suggests those nutrients may reduce the risk of age-related macular degeneration.

All about  "EYE"