Food Cures (42 page)

F
or more than 75 years, Nat was a glutton for the printed word. He would read anything—newspapers, magazines, even instruction manuals—but he loved books best. He was active, with plenty of friends and a terrific family, but he was happiest when he could relax with a good novel. So it was particularly devastating when Nat lost most of his sight to macular degeneration. Now, when he finally has all the leisure time in the world, he can’t read much more than the large type of the newspaper headlines. Instead of reading novels, he settles for listening to television and radio. It breaks his family’s heart. My heart, because I’m a part of Nat’s family—he is my husband’s grandfather.

Vision loss, and the resulting loss of quality of life, is all too common—cataracts affect about half of all Americans over age 80, and approximately 13 million Americans have macular degeneration. In the past decade, research has pointed to nutrition as one of the factors that might reduce the risk
and
slow the progression of these disorders. I wish that this information had been available back when Nat was still in his prime, when it might have helped to preserve at least some of his sight. I’m sure he would have embraced the changes I’ll discuss in this chapter if it meant he could spend even one more quiet hour with the mysteries he loves so much.

WHAT AFFECTS
CATARACT
DEVELOPMENT?

Light enters the eye through the pupil, the round, black opening at the center of the iris. Behind the pupil is the lens, which catches the incoming light and focuses it onto the retina at the back of the eye.

A cataract is formed when protein fibers in the lens change shape and clump together, clouding the normally transparent lens. This is similar to the process that turns the protein in egg albumin from clear to white when cooked. In fact, most well-developed cataracts look milky white, although in some rare cases, the lens can turn yellow or brown instead.

Cataracts develop slowly, over a period of years. But even before a cataract can be seen from the outside, vision can become blurry or cloudy, like looking through a fogged windshield. Other possible symptoms include worsened night vision, faded color vision, and starburst or halo effects around bright lights. Because cataracts can be surgically removed, these symptoms are only temporary—after surgery you may need glasses to see detail, but your sight will be clear.

No one knows exactly what causes eye proteins to clump and create a cataract. Many scientists blame unstable molecules known as free radicals, which can wreak havoc throughout the body, causing destruction and disease wherever they go through a complex chemical process called
oxidative stress
. And what creates free radicals? Well…the single greatest cause is just being alive. Natural metabolic processes from normal body functions like breathing and digesting food generate lots of free radicals, and unless they are neutralized, they build up over time. That’s why our bodies seem to deteriorate slowly with age—it’s the accumulated damage from years of free radical attacks. Anytime there is a major change in the way our bodies work, there is a potential increase in the number of free radicals produced, which is why many metabolic disorders, especially diabetes, are considered risk factors. People with diabetes have a 40 percent increased risk of cataracts…and their cataracts develop faster and earlier than those in people without blood sugar problems.

Two other major causes of free radicals are smoking and ultraviolet radiation from sunlight. That’s why all cataract prevention strategies must include a commitment to stop smoking and reduce exposure to sunlight. Cataracts can also be caused by surgery for other eye problems, traumatic eye injury, or long-term use of corticosteroids. In very rare circumstances, genetic anomalies can create cataracts in newborn babies or infants.

HOW FOOD AFFECTS CATARACTS

The ultimate prevention for cataracts is simple: Never grow old.

For those of you who can’t stop time, nutrition and lifestyle changes are your best bets for preventing or slowing the development of cataracts. Although research has not absolutely, positively proved nutrition’s role in cataract prevention, science provides ample circumstantial evidence that eating the right foods could help…and I know for certain it can’t hurt!

For cataract prevention, the primary nutrients you want to pay attention to are antioxidants and the B vitamins.

ANTIOXIDANTS: VITAMIN C AND VITAMIN E

As the name suggests, anti
oxidants
fight the
oxidative
stress caused by free radicals. There is no single antioxidant—rather, it is a broad category that includes vitamin C, vitamin E, lutein, beta carotene, and any number of other substances that can neutralize free radicals. All vegetables and fruits contain antioxidants, so eating a diet rich in those foods should help prevent cataracts. The few research studies that have been conducted confirm it.

The Nurses’ Health Study revealed that women who ate a very healthy diet full of all kinds of antioxidants from vegetables, fruits, and whole grains were
half as likely
to develop cataracts as women who did not eat such a healthy diet. Those benefits were from food alone—if the women took vitamin C supplements, they actually lost that protection and had the same risk of cataracts as women who ate unhealthy diets. Why? No one knows. The truth is, those results were unexpected. We know that vitamin C is a potent antioxidant. We know that people who get lots of vitamin C in their foods (as measured by blood levels of vitamin C) have a reduced risk of cataracts, and at least one earlier study had shown that people who took supplements were less likely to have cataracts. And finally, we know that when laboratory mice eat vitamin C supplements, they have a reduced risk of cataracts. So this finding that vitamin C supplements did not reduce the risk for people is confusing.

The story on vitamin E is equally confusing. Although some research has shown that taking vitamin E supplements reduces the risk of cataracts, others show that the supplements almost
doubled
the risk of cataracts. No one knows why the science is so conflicting, for both vitamins. Regardless of the reasons,
the big-picture message is clear:
Eating lots of fruits and vegetables, including those rich in vitamins C and E, may be your best protection against cataracts.

BEST SOURCES OF FOOD ANTIOXIDANTS: TOP 20 FRUITS,
VEGETABLES, AND NUTS
(as measured by total antioxidant capacity per serving size)

Source: USDA; Journal of Agricultural and Food Chemistry, June 9, 2004

ANTIOXIDANT: LUTEIN

Lutein is another antioxidant of tremendous interest to eye health researchers. Like all antioxidants, lutein can defuse potentially damaging free radicals. In addition, lutein may also prevent the development of some free radicals because it absorbs blue light—part of the short-wave spectrum of cataract-causing sunlight.

The Beaver Dam Eye study, which followed nearly 5,000 people to see what factors affected aging-related vision disorders, showed that people who ate large amounts of lutein-rich foods had a 20 percent reduced risk of cataracts compared with people who got very little lutein in their diets. Similar results were reported from the Nurses’ Health Study and the U.S. Male Health Professionals Study. I don’t recommend lutein supplements, however. No one knows everything there is to know about the effects of individual nutrients. It could be, for example, that lutein works best only when paired with other antioxidants, or with certain vitamins and minerals. Right now, the only solid information we have supports eating a diet full of lutein-rich leafy green vegetables,
plus
an abundance of other antioxidant-rich vegetables and fruits.