Life Extension Magazine May 2006
Nutritional Strategies for Preventing Age-Related Vision Loss
By Edward Rosick, DO, MPH, MS
By the age of 65, a shocking 30% of Americans suffer from drastic vision problems that are not correctable with glasses or contact lenses. The two most common causes of vision loss in older adults are cataracts and age-related macular degeneration.
While millions of doctors and their patients view these insidious conditions as inevitable consequences of the aging process, Life Extension has long maintained that potent antioxidants can play a critical role in supporting healthy ocular function with aging.
Mainstream medicine is finally recognizing the critical link between eye health and nutrition. Recent articles in prestigious scientific publications such as the Journal of the American Medical Association and Ophthalmology verify the importance of antioxidant nutrients in preserving vision. Moreover, emerging studies indicate that suppressing levels of potentially dangerous C-reactive protein and homocysteine is likewise essential to maintaining eye health with aging.
Health-conscious adults can thus preserve their vision by using targeted nutritional remedies and managing the risk factors that directly threaten eye health. This well-rounded, preventive approach can help ensure healthy vision over the course of a lifetime.
The sense of sight is a wondrous gift of nature that begins at the moment of birth and ideally lasts a lifetime. As we age, however, both the lens and retina of the eye may suffer deterioration that can lead to near or even total blindness. Such problems affect nearly one third of elderly adults. Two of the most common eye diseases afflicting the elderly are cataracts and age-related macular degeneration.
Cataracts Are Not Inevitable
Most people in their sixties or seventies know someone who has had cataract surgery. Because cataracts are so common, many people assume that they are another inevitable consequence of aging. However, with a few essential precautions and the judicious use of targeted nutritional supplements, this does not have to be the case at all.
Cataracts are a clouding of the eye lens, which is mostly made up of protein and water. Although cataracts can begin to form before the age of 40, it is not until much later that they begin to adversely affect millions of older adults. As we grow older, new cells replace most of the cells in our bodies. However, the eye lens experiences no such cell turnover—thus the lens you are born with is the lens that will be with you the rest of your life.
Normally, light passes through the eye lens without distortion, as though the lens were made of perfectly clear glass. Over five or six decades, your eye lens can be damaged by ultraviolet (UV) radiation from sunlight, as well as by oxidative stress generated by free radicals. If this damage is significant enough, cataracts (which are actually “clumps” of protein in the lens) eventually form.
In their early stages, cataracts may not be much of a problem. Over years and decades, however, cataracts may grow larger, making it more difficult, or even impossible, to see clearly. According to people with cataracts, the visual sensation is like trying to look through a dirty, cloudy window.
While most cataracts are related to aging, other circumstances give rise to other types of cataracts. These include: congenital cataracts, which can affect infants and young children; secondary cataracts, which develop as a result of certain illnesses, such as diabetes, or in conjunction with the use of certain medications, such as long-term use of corticosteroids; and traumatic cataracts, which can form in the eyes following a traumatic injury or other event.
A century ago, having cataracts meant having to wear thick, unsightly glasses and using magnifying glasses to read even the largest print. Today, thanks to modern surgical techniques, removing cataracts and implanting an artificial lens is an almost routine surgical procedure. Yet for all of its positive aspects, cataract surgery comes with a price. The total cost of cataract surgeries performed in the US is estimated to be $3.5 billion a year.
Cataract surgery also entails additional health-related costs. Surgical complications are rare, but certainly not unheard of. Some 20-30% of those who undergo cataract surgery develop a subsequent clouding of the lens capsule, the part of the lens that is often left in the eye to hold the new synthetic lens in place. If the capsule becomes cloudy (this is known as an after-cataract), the patient will require additional surgery to restore clear vision. Moreover, in rare cases, cataract surgery can lead to more serious complications, such as swelling of the eye, infections, and even blindness.
Vitamins That Help Prevent Cataracts
Scientists believe that the formation of cataracts is in part due to oxidative damage. Thus, it makes sense that well-known antioxidants such as lutein and vitamins A, C, and E could help retard the formation of these vision robbers. Indeed, numerous studies show that antioxidant vitamins can help counter the destructive effects of cataracts.
In the well-known Beaver Dam Eye Study, scientists examined the relationship between dietary intake of antioxidant nutrients and the incidence of cataract formation in a cohort of 1,354 adults, aged 43-84, over seven years.1 Those who consumed foods that are high in anti-oxidant vitamins had a diminished risk of developing cataracts. According to the researchers, the data from this prospective study “are consistent with a possible protective influence of lutein and vitamins E and C on the development of . . . cataracts.”
Other, larger-scale studies suggest that vitamin A may help protect against cataracts. For example, in the Nurse’s Health Study, researchers followed 50,828 women, aged 45-67, for eight years. Women who consumed the most vitamin A had a 39% lower risk of developing cataracts than women who consumed the least vitamin A.2
Blindness and Other Perils of ARMD
Age-related macular degeneration (ARMD), a debilitating eye condition that affects at least 10 million men and women in the US, is the leading cause of legal blindness in people 55 and older. Unlike cataracts, ARMD does not adversely affect the eye lens; instead, it causes a devastating deterioration of the macula, the specialized area of the eye’s retina that helps maintain the sharp, detailed vision required for tasks such as reading and driving. When the macula deteriorates due to ARMD, affected individuals experience a world of fuzzy, indistinct shapes and washed-out colors.
The two forms of ARMD are dry, or atrophic, and wet, or exudative. Dry ARMD is by far the most common, occurring in about 90% of those suffering from the disease. The wet form is seen in the remaining 10%. In the dry form, yellow deposits called drusen accumulate underneath the retina over a period of years, which causes the macula to thin and lose function. By contrast, wet ARMD can occur very rapidly over two or three years, and accounts for most of the major vision loss attributed to macular degeneration. This devastating condition is caused by abnormal blood vessels that grow across and under the macula and lead to scar tissue formation, which eventually damages and destroys the macula. While treatments can slow the abnormal blood vessel growth that accompanies wet ARMD, there is no cure for either wet or dry macular degeneration.
Inflammation, C-Reactive Protein, and ARMD
While scientists are still investigating why ARMD affects some aging adults but not others, new research points to inflammation’s role in this devastating disease. As Life Extension readers are aware, multiple lines of research have demonstrated that chronic inflammation may contribute to various age-related diseases such as cancer, Alzheimer’s, and heart disease. In fact, biological markers of inflammation, such as C-reactive protein (CRP), may be a harbinger of ARMD as well as a warning sign for heart disease risk.
C-reactive protein is produced and released by the liver in response to an acute inflammatory stimulus. Multiple studies have shown that CRP levels are elevated in multiple inflammatory, infectious, and neoplastic diseases, ranging from rheumatoid arthritis and tuberculosis to cancer and heart disease. Data gleaned from newly published studies suggest that ARMD may be yet another inflammatory disease that afflicts middle-aged and elderly adults.
Two recent papers examined whether elevated C-reactive protein levels correlate with the risk of developing ARMD. In one article, published in the prestigious journal Ophthalmology, researchers recruited 79 elderly men and women with ARMD, along with 77 unaffected control subjects.3 Individuals suffering from ARMD exhibited higher CRP levels than did unaffected individuals, and this difference was statistically significant.
A case-control study of 930 patients also examined the relationship between C-reactive protein and ARMD risk. Published in 2004 in the Journal of the American Medical Association (JAMA), this investigation found that CRP levels were significantly higher among subjects with intermediate or advanced ARMD. According to the study authors, “elevated CRP level is an independent risk factor for [ARMD] and may implicate the role of inflammation in the pathogenesis of [ARMD].”4