Eye Health and Antioxidants
Do You Get Enough Antioxidants For Your Eyes?
There are many antioxidants that work in your favor for eye-health.
For example, vitamin A is a powerful antioxidant that is known
primarily for its effect on the retina, especially that of improving
night vision. The body converts vitamin A, found in animal tissues,
to the fat-soluble compound retinol for storage in the liver. Once
vitamin A is stored in the liver, zinc is needed to liberate it for
transport to the eyes as needed. Vitamin A is found in fish, fish
liver oil, eggs, and liver.
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It is possible to use beta-carotene, one of a
class of substances known as carotenoids, as a substitute
for vitamin A, because beta-carotene is a precursor of
vitamin A and is converted into retinol in the liver. Eye
experts have found that taking supplemental vitamin A
palmitate in combination with manganese has been helpful to
some people with glaucoma.
Beta-carotene sources in food vary immensely. Sweet potatoes
top the list; raw carrots follow. At the low end are apples.
In between lie a host of fruits and vegetables, including
purslane (best known as a common weed, but now also grown
commercially for use in salads), butternut and hubbard
squash, mangoes, dandelion greens, kale, turnip greens, beet
greens, red pepper, papaya, cantaloupe, Swiss chard, fresh
or dried apricots, bok-choy, mustard greens, collards, and
tomatoes. |
Also included are broccoli, nectarines,
prunes, tangerines, asparagus, romaine lettuce, avocados,
plantains, savoy cabbage, Brussels
sprouts, green peas, peaches, oranges, and bananas.
In natural sources, you not only get
beta-carotene, but all the carotenoids as well, plus a host of
other compounds necessary for optimum health. People who have
diabetes may lose their ability to convert beta-carotene to
retinol, and so must take vitamin A in its fat-soluble form.
Fat-soluble vitamin A is found in fish liver oil, eggs, and
liver.
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Air pollution, nitrates, nitrites (commonly
used in fertilizers), and cooking and canning destroy or
weaken vitamin A's effectiveness.
The carotenoids, of which beta-carotene is
only one, are gaining ground among natural ways of achieving
eye health. In addition to beta-carotene, two carotenoids
that relate directly to eye health are lutein, which is
present in spinach, marigolds, sunflowers, and kale, and
lycopene, which is found in tomatoes.
Lutein has received considerable attention, especially for
the problem of macular degeneration. Studies suggest that a
high intake of foods rich in lutein may protect the retina
from oxidative damage leading to degeneration of the macula.
Super foods include kale, spinach, collard greens, broccoli,
Brussels sprouts, leaf lettuce, green peas, and summer
squash. |
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Foods that contain a moderate amount of lutein include cabbage,
marigold, carrots, corn, green beans, and tomatoes. Lutein is also
available in supplement form, either by itself or as part of one of
the eye therapy supplementations. However, lutein and beta-carotene
should not be taken together at the same time because they compete
for absorption in your gut. Therefore it is better to take your
beta-carotene, say, at breakfast and your lutein with your dinner,
especially if you're having a salad dressed with olive oil. Both
lutein and beta-carotene are more readily absorbed with a bit of
fat. |
