AMD: Healthy Eating is Essential for Saving Your Vision
Age-related Macular Degeneration (AMD) is one of the most common causes of irreversible vision loss in developed countries. Estimates of how many people are affected vary considerably, but the percentage of the population with it increases with age. While only 2% of people aged 50 to 59 have the disease, the incidence rises to nearly 30% by the age of 75 years. Therefore, the greatest risk factor for developing this condition is age. Please see our article titled “AMD: The Sneak Thief of Vision” for more information.
In the retina, the macula is located at the center; it is the exact point on the retina that we use to see small details and appreciate colors and shapes. Degeneration begins with small deposits around the macula area called drusen and with small retinal holes. AMD begins with thinning of the retinal tissue and small deposits known as drusen in and around the macula. Early on, the vision is not greatly affected, but will progressively change over time. About 20% of the time, this dry type of degeneration transforms into what is known as wet AMD, characterized by fluid leakage into the area and the growth of fragile new blood vessels which can break and leak into the back of the eye. Macular degeneration can be devastating to the vision, causing the loss of the ability to see well enough to read, appreciate color and even to recognize the faces of loved ones.
AMD is still not completely understood, but may be due to oxidation reactions in the retina. The large, years-long Age-Related Eye Disease Study (AREDS) did show that antioxidants were helpful in preventing up to 25% of the progression from early- to late-stage AMD.
Presently, there is no cure for AMD, but it has been shown that its progression can be slowed, especially when diagnosed fairly early in the process. Preserving vision in the first eye has not been as successful as preserving it in the second eye; this is thought to be the result of better and more frequent monitoring of the second eye as the first eye is followed for changes.
Research is progressing in genetic testing for AMD which can help identify those at risk to develop this condition so steps can be taken for early diagnosis and delay progression from dry to the wet forms.
Recent studies are showing that eating a healthy diet and/or using specific nutritional supplements is useful in slowing the disease down, as well as lowering the risk of cancer and delaying Alzheimer’s Disease or other dementias.
Supplements and Diet
AREDS showed that increases from five to 13 times the recommended daily allowance of beta-carotene, vitamins C, E and the mineral zinc were effective in reducing the rate of progress of AMD. A later phase of AREDS modified that formulation to eliminate beta-carotene and added the anti-oxidants lutein and zeanxanthin. A third anti-oxidant, meso-zeanxanthin, has been shown in the most recent research to be especially helpful, particularly in combination with the first two. Researchers pointed out that a diet rich in several different antioxidants was more effective than those which relied on high amounts of any single one.
In order to get the vitamins, anti-oxidants and minerals linked with lower risk of AMD, specific recommendations are that you should consume daily six or more servings of vegetables and fruits, and include one cup of dark green and another of orange vegetables each week, three or more servings of whole grains, four to six ounces of meat, poultry or seafood (or bean equivalents), five to seven teaspoons of oils like olive or canola and about one ounce of nuts.
Several large studies also link eating fish at least twice a week with substantially lower chances of developing AMD. Too much total fat, particularly polyunsaturated fats which are found in some species of fish, may actually increase the risk, however. This is thought to be because the chemical structure of polyunsaturated fat seems more vulnerable to oxidation reactions that are thought to cause damage to the eye.
High-glycemic index foods like sweets and refined grains such as white rice, pasta, potatoes and white bread have been linked to a higher risk of developing AMD, as well as an increasing risk of faster progression and higher severity over the course of the disease. It is thought that perhaps too many refined carbohydrates encourage inflammation and tissue damage; also, the shortage of nutrients and phytochemicals from healthful foods could also explain their higher risk for developing AMD. Switching from “fast carbs” to their “slow carb” counterparts such as whole grain pasta and breads give a much slower rise and fall of blood sugar, less likely to result in inflammation and tissue damage over time.
Current research indicates that if ocular supplements are taken in addition to the dietary recommendations above should contain vitamins C and E, zinc, copper, lutein, zeanxanthin and meso-zeanxanthin. The last, meso-zeanxanthin, has only recently been isolated and may not be available in all supplements, so it is important to read labels and compare the contents before purchasing them.
Healthy Eating is its Own Reward
It should be evident that eating a healthy diet with plenty of fruits, vegetables, whole grains and lean meats has plenty of benefits, even if the increased risk of AMD without them is ignored. Other studies show that a diet such as this is helpful in delaying onset of Alzheimer’s Disease for those at risk for that and other dementias. We all know, too, that eating right can help prevent certain cancers and that it doesn’t hurt our cardiovascular health, either.
Staying active, eating well and enjoying life are all important to keeping us healthy and happy; it’s a winning strategy, no matter what angle you’re looking at it from.