Carotenoids Are Even Better than Carrots

he price of medical care in the United States continues to increase disproportionately every year, and there are no signs that this trend is going to stop in the near future. While people debate the causes of this runaway inflation in health care costs, it cannot be denied that a major factor is the increasing use of technologically advanced (and expensive) equipment, especially for surgeries.

Just 30 years ago (a relatively short time in the history of medicine), having cataract surgery, one of the most common operations in America, was quite a big deal. Patients were often hospitalized for three or four days after their surgery, and subsequently, most had to wear glasses with thick, unsightly lenses for their rest of their lives, giving them the appearance of Mr. Magoo.

Today, for those who have cataracts and decide to have the operation, both the procedure and the outcome are far less complicated. Cataract surgery is generally done not in the hospital, but in an outpatient surgery clinic. The procedure itself usually takes less than an hour, and vision is often restored to near normal without the use of heavy, burdensome glasses.

Cataract Surgery Does Not Come Cheap

Of course, cataract surgery does not come without a hefty price. It is estimated that the cost of all cataract operations in the United States is in the neighborhood of 3.5 billion dollars annually. Considering that the number of people reaching their sixties and seventies (when this operation is commonly performed) is increasing every year, that amount isn’t likely to go anywhere but up.

Besides the financial burden, there can be other problems associated with cataract surgery. Although complications are rare, they’re certainly not unknown. In twenty to thirty percent of people who have the operation, there is eventual clouding of the lens capsule, a part of the lens that is ordinarily left in a patient’s eye to hold the new plastic lens in place. If the capsule becomes cloudy, the patient may have to undergo laser surgery to restore clear vision. In other people, more serious complications can develop, including severe swelling of the eye, infections, and even blindness.

Are Cataracts Inevitable with Aging?

Many doctors (and patients) assume that cataract formation is a rite of passage in the aging process. As a person grows older, most cells in the body are continually replaced by new cells as the old ones die off. The lens of the eye, however, has no such turnover—the cells don’t die, so the lenses that you’re born with are the lenses that will be with you the rest of your life (unless, of course, you have them removed during cataract surgery!).

The lens of the eye is made mainly of water and the protein collagen. Normally, light passes through the lens without distortion, as if it were made of perfectly clear glass. Over a person’s lifetime, however, the lens can be damaged by environmental stressors, such as ultraviolet (UV) radiation from sunlight, and by oxidative stress caused by free radicals. The latter are damaging molecules that arise not only from normal chemical reactions in the body but also from UV radiation and exposure to noxious chemicals, such as those found in cigarette smoke.

After four or five decades, such cumulative damage can lead to a clouding of the lens—a cataract. Early on, cataracts do not pose a serious vision problem, but as they grow larger and denser, vision becomes blurry, colors fade, and night vision becomes very poor.

Age-Related Macular Degeneration—A Leading Cause of Blindness

Besides having to worry about cataracts impairing their vision—if only temporarily, because it’s so easy to restore—the elderly (all of us, actually) also face the far worse prospect of developing age-related macular degeneration (AMD). In fact, AMD, which affects 10 million men and women in the United States, is a leading cause of permanent blindness in people over 55.

In AMD, there is a devastating deterioration of part of the retina (the “projection screen” of the eye) called the macula. The macula, visible as a yellow spot in the center of the retina, is where images of the outside world are “recorded” and immediately sent to the brain via the optic nerve. The macula allows people to discern fine detail that’s needed for tasks such as reading, driving, or working at a craft.

Dry or Wet, AMD Is Not Curable

There are two forms of AMD: atrophic, or dry, and exudative, or wet, which account for about 90% and 10%, respectively, of all cases of the disease. In the dry form, tiny lesions called drusen accumulate underneath the retina, where they can cause the macula to become thin and lose function.

Wet AMD, which accounts for about 90% of all the major vision loss attributed to macular degeneration, is caused by abnormal blood vessels that grow across and under the macula and cause the formation of scar tissue. This can damage or even destroy the macula. Although there are treatments that can slow the formation of abnormal blood-vessel growth in wet AMD, there is no cure for either wet or dry macular degeneration.

Lutein and Zeaxanthin Are Vital for Good Vision

Two of the most important supplements for maintaining good vision and combating age-related visual loss are lutein and zeaxanthin. Both are carotenoids, naturally occurring pigments that are found in many fruits and vegetables (not just carrots). Their significance in the eye is that they are the two primary pigments of the macula, which owes its yellow color to them.

It is believed that these carotenoids help protect the lens and the retina from the damaging effects of solar UV radiation. It’s also thought that the vision-protecting effects of carotenoids come from their chemical activity as antioxidants, which can squelch the harmful effects of free radicals in both the lens and the retina.

Lutein and Zeaxanthin Stop the Formation of Cataracts

There is a growing body of scientific evidence showing that lutein and zeaxanthin can offer significant protection against the development of cataracts. Three studies done in the late 1990s showed that both men and women who had a high intake of lutein and zeaxanthin had significantly lower risks of developing cataracts than people who had a low intake of these compounds.^1–3

Lutein Improves Vision in People with Cataracts

A very recent study reported that lutein supplements can help improve vision in people who already have cataracts.⁴ In this randomized, double-blind study, 17 men and women (aged 55–73) who had cataracts were given one of three supplements: 15 mg of lutein, 100 mg of vitamin E in the form of alpha-tocopherol, or placebo, three times a week for up to two years. At the end of this period, the researchers found that vision had been stabilized in the patients who were taking the vitamin E supplements. In those taking placebo, there was a decline in vision, as would be expected in people with untreated cataracts.

The exciting news, however, was that the people taking lutein supplements had experienced a statistically significant improvement in vision, in terms of visual acuity and glare sensitivity. The authors concluded that “. . . a higher intake of lutein, through lutein-rich fruit and vegetables or supplements, may have beneficial effects on the visual performance of people with age-related cataracts.”

Lutein and Zeaxanthin Can Protect Against AMD

Besides offering protection against cataract formation and the degradation of vision caused by cataracts, carotenoids are also proving to be powerful weapons in the fight against AMD. A study published in the Journal of the American Medical Association in 1994 examined the role of lutein, zeaxanthin, and other supplements in stopping the development of this terrible disease.⁵

It was found that people with a high intake of lutein and zeaxanthin had a significantly lowered risk for developing the disease. The authors stated that “. . . the risk for AMD was reduced by 43% among people whose consumption placed them in the highest quintile of dietary carotenoid [lutein and zeaxanthin] intake compared with those in the lowest quintile.” (A quintile is a 20% segment—one-fifth—of the whole.)

Zeaxanthin Protects Against Photodamage

A more recent study, done on Japanese quail, of all things (you’ll see why in a moment), showed that long-term supplementation with zeaxanthin protects the photoreceptors of the retina against light-induced damage.⁶ The quail were fed one of three diets: a commercial turkey diet, a custom diet with a 90% reduction in carotenoid content, or that same custom diet but enriched with zeaxanthin.

Japanese quail (Coturnix japonica)

Like all primates, many bird species concentrate carotenoids in their retinas, albeit not in their macular pigment. The researchers used Japanese quail because their retinas selectively accumulate both dietary lutein and zeaxanthin, with a preference for the latter.

The results of the study were very complex, in terms of the many different correlations found among various experimental parameters, and they were somewhat contradictory. Nonetheless, the authors were able to reach the following conclusion: “In summary, data presented here clearly demonstrate that zeaxanthin protects photoreceptors from damage by white light, and thus validate—at least for zeaxanthin—the long-held hypothesis that the retina is protected by carotenoids in macular pigment.”

The Wisdom of the Body

An interesting aspect of the quail study involved the zeaxanthin levels actually found in the birds’ eyes. As expected, they were much higher than normal (3 to 5 times higher) in the retinas of the quail given the zeaxanthin-supplemented diet. In the other two groups of birds, however, the retinal zeaxanthin levels were the same, even though one group had been fed a diet that was severely deficient in carotenoids. Further investigation showed that the zeaxanthin levels in the serum, liver and fat of the carotenoid-deficient birds were 2 to 5 times lower than in the normally fed birds.

So what had happened? Evidently, the carotenoid-deficient birds had scrounged existing zeaxanthin from throughout their bodies and diverted it to their eyes, where it was needed most. Clever birds!

Don’t Let Age Steal the Light from Your Day

Growing older may be an inevitable part of life, but suffering from many of the afflictions of the elderly need not be. By using natural supplements such as lutein and zeaxanthin, as well as antioxidant vitamins, you can help protect your eyesight from the ravages of cataracts and AMD.

Along the way, you can also protect your pocketbook from the high cost of surgery for those diseases. In fact, it has recently been calculated that if patients with moderately advanced AMD followed a supplement regimen consisting of zinc, vitamins C and E, and beta-carotene (a vitamin A precursor), the savings for the U.S. health care system could be $1.56 billion dollars over the next ten years.⁷ That may seem like chump change to spendthrift politicians, but it’s serious money in the real world, and the medical establishment would do well to embrace the value of supplements for maintaining healthy vision.

References

1. Lyle BJ et al. Antioxidant intake and risk of incident age-related nuclear cataracts in the Beaver Dam Eye Study. Am J Epidemiol 1999;149(9):801-9.
2. Brown L et al. A prospective study of carotenoid intake and risk of cataract extraction in US men. Am J Clin Nutr 1999:70:517-24.
3. Taber LC et al. A prospective study of carotenoid and vitamin A intakes and risk of cataract extraction in US women. Am J Clin Nutr 1999;70:509-16.
4. Olmedilla B, Granado F, Blanco I, Vaquero M. Lutein, but not alpha-tocopherol, supplementation improves visual function in patients with age-related cataracts: a 2-y double-blind, placebo-controlled pilot study. Applied Nutr Invest 2003;19:21-4.
5. Seddon JM et al. Eye Disease Case-Control Study Group. Dietary carotenoids, vitamins A, C, and E, and advanced age-related macular degeneration. JAMA 1994;272(18):1413-20. Published erratum appears in JAMA 1995;273(8):622.
6. Thompson LR, Toyoda Y, Delori FC, et al. Long term dietary supplementation with zeaxanthin reduces photoreceptor death in light-damaged Japanese quail. Exp Eye Res 2002;75:529-542.
7. Reuters Health. Vitamins to save eyes could save money too—study. Oct. 23, 2002. (Quoting Dr. Sanjay Sharma of Queens University in Kingston, Ontario.)

Dr. Rosick is an attending physician and clinical assistant professor of medicine at Pennsylvania State University, where he specializes in preventive and alternative medicine. He also holds a master’s degree in healthcare administration.