How Chickens Decrease the Risk of Macular Degeneration
19 Mar 2004
Today seven million North Americans suffer from a devastating disease, macular degeneration. No longer can they enjoy the simple pleasures of reading or watching TV. These unfortunate people have lost their central vision. And although there’s no cure for macular degeneration there are ways to reduce the risk of developing this disabling problem.
The retina acts like the film of a camera conveying images to the brain. The big picture is sent by detectors present throughout the retina. The small picture, central vision, is sent by the macula. It’s situated directly behind the lens, about the size of this "o".
Stare someone in the eye at a distance of 20 feet and your looking at the macula. All the rest is peripheral vision. And it’s impossible to drive a car or see your grandchildren smile with only peripheral vision.
People who begin to develop macular degeneration complain of blurred or fuzzy vision. They have the illusion that straight lines, such as sentences on a page are waxy. Patients also become aware of dark or empty areas in central vision.
Several risk factors have been linked to macular degeneration. Some people have a family history of this disorder. Excessive sunlight exposure, smoking, female gender and patients who have a light-coloured iris are at greater risk.
Dr. John Landrum, at Florida International University, Miami, Florida is a world expert on macular pigments. Lutein and zeaxanthin Dr. Landrum reports, are the two primary pigments, also called carotenoids, present in the macula.
Dr. Landrum studied the concentrations of pigments in the eyes of those with and without macular disease. This study revealed that people with the highest intakes of lutein and zeaxanthin had a 43 per cent less risk of macular degeneration.
This is not the first study that has linked a lack of carotenoids to macular disease. A report from the National Institute of Health found that those with the lowest dietary intake of carotenoids had a higher risk of macular degeneration.
Dr. Linda Nebeling of the National Cancer Institute recently presented data showing the overall decline of lutein intake. This was particularly striking in those groups at risk for macular degeneration. For instance, since 1987 lutein intake has decreased by 16 per cent in men and women aged 40 to 69.
Not known is how much lutein and zeaxanthin are needed to maintain good vision. Dr. Landrum and his colleagues have shown that 30 milligrams (mg) of carotenoids daily result in large increases of lutein and zeaxanthin in the blood and macula.
In another study subjects took only 2.4 mg of lutein daily for six months. But with even these low doses blood levels of lutein and zeaxanthin increased between 20 and 300 per cent. And there was a significant increase in the macula.
Researchers believe that lutein and zeaxanthin protect the macula by absorbing harmful blue light from the sun’s rays. In addition, they act as antioxidants that neutralize free radicals.
Free radicals are harmful molecules, the end products of oxygen metabolism. In addition, free radicals are also triggered by tobacco smoke, air pollutants, certain drugs and environmental toxins.
So how can you reduce the risk of macular degeneration? The best way is to ensure that you have an adequate dietary intake of lutein and zeaxanthin. This means eating fruits and leafy vegetables that are rich in these carotenoids. And to take supplements of these carotenoids if you have a faulty diet.
But there is another way to obtain lutein that most people are not aware of. Several week ago I mentioned how the Naturegg brand, the number one Omega-3 egg in Canada was rich in omega-3 fatty acids which helps to fight heart disease. The yolk of these eggs are also rich in lutein.
This is why I recently advised a patient with failing eyesight to eat omega-3 eggs. She quickly asked, "But won’t it cause an increase my cholesterol?" I reassured her that several studies show that enjoying eggs for breakfast does not increase blood cholesterol in most patients. It’s why I’ve urged readers for years to trust the farmers and to cast a jaundiced eye at packaged supermarket foods.
