It's a case of putting the cart before the horse. The horse is a small number of preliminary studies which have suggested that substances in certain dark green, leafy vegetables are associated with the prevention of age-related macular degeneration -- the leading cause of irreversible blindness in older people and the culprit behind at least some loss of vision in more than 13 million Americans. The cart being pushed way out in front is YourLife Eye Care Complex, a supplement manufactured by Leiner Health Care Products that contains, according to the label, "essential nutrients for healthy eyes."
It's true that the supplements have lutein and zeaxanthin --antioxidants in spinach and other greens that have been linked to a reduced risk of age-related macular degeneration in a handful of research projects. And the link appears to make scientific sense. Both lutein and zeaxanthin are contained in the macula, a tiny portion of the retina at the back of the eye that allows people to see details clearly and thereby enables activities ranging from reading to driving. Scientists theorize that the 2 substances help block out harmful ultraviolet rays that cause damage from free radicals, toxic compounds that injure body cells. If enough of those substances is not present, the thinking goes, the cells of the macula could break down, or degenerate, creating vision problems.
But ophthalmologist Johanna Seddon, MD, says that the theory is just that -- despite the fact that marketing materials for YourLife Eye Care Complex make much of a Harvard study she headed suggesting that lutein and zeaxanthin protect against age-related macular degeneration. The reason for her caution is that she looked at people's consumption of foods high in the 2 antioxidants. Her finding was that those who ate a diet rich in spinach and collard greens were much less likely to have age-related macular degeneration than those who ate relatively little of those foods. Her study did not evaluate whether antioxidants per se could prevent the onset of the disease.
"What I tell my patients," Dr. Seddon says, "is that at this point the connection between substances in vegetables and age-related macular degeneration is simply an association." In other words, we don't have any proof of cause and effect. Lutein and zeaxanthin may simply be markers for something else in food that protects the macula, so the best thing is to eat a variety of vegetables, particularly dark green leafy varieties. These include not just spinach and collard greens but also kale, mustard greens, and turnip greens.
YourLife Eye Care Complex contains some spinach, but it has only 70 milligrams, or 1/400 of an ounce. The pills also contain vitamin A, a nutrient not lacking in most Americans' diets; the amount of vitamin C you'd get in half an orange; some selenium; and (why is anybody's guess) an infinitesimal amount of bilberry -- a cousin to the blueberry.
PHOTO (BLACK & WHITE): A bottle of 50 tablets, incidentally, retails for $13.99. The company suggests taking up to 3 tablets a day. You'll protect your eyes better by wearing a hat with a brim and sunglasses that block ultraviolet light than by taking these pills.