Bad Vision: The Four Worst Diet Habits for Eye Health

As a follow-up post to last week's discussion of the best foods for eye health, today we'll go over the four absolute worst dietary things you can do for your eyes.

1) Smoke:
Okay, sure, it’s not technically a food, but you do “ingest” tobacco smoke. And smoking is at the top of this list for the simple reason that it is the most preventable cause of eye health problems, including macular degeneration and cataracts.

The various toxins and carcinogens contained in tobacco smoke enter into your bloodstream via your lungs, and from there they head straight for your eyes. These toxins can affect retinal function, and they can exacerbate macular degeration.

2) Eat a High-Fat Diet:
A diet centered around high-fat foods is of course unhealthy for many reasons, including causing cardiovascular problems like ateriosclerosis. And just as these transfats can clog the arteries to your heart, they can also clog up the arteries to your eyes, and this can cause damage to your optic nerve and potentially result in loss of vision.

Despite their value as part of an occasional energy-dense meal, fats (especially transfats, like partially hydrogenated soybean oil, butter and margarine) should never play an excessive role your diet.

3) Eat too much salt:
We’ve harped on how salt is shamelessly overused in restaurants and in many prepared foods. Well, here’s another reason to be concerned about your sodium intake: high sodium levels in your body can lead to high blood pressure, which can restrict the flow of blood to the eyes. Remember, blood nourishes your cells, and it also takes pollutants and waste products away from your cells. This includes the cells of your optic nerves and your retinas.

4) Be Severely Overweight:
According to the Mayo Clinic, “being severely overweight increases the chances that early or intermediate macular degeneration will progress to the more severe form of the disease.”

Furthermore, if you're overweight, you run a high risk of having Type II (adult onset) diabetes. And diabetes, especially if not managed properly, can cause all sorts of problems with the eyes, including lost vision due to leaking blood vessels in the retina.

Let me just make a brief apology for the tone of this if this post. It sounds so... admonishing! My goal with this post is not to depress you, but just to make you aware that the foods you eat--and how well you take care of your body--can have a meaningful impact on your vision.

Let's say it once again, with feeling: eat right to see right!

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Eat Right to See Right: Foods for Better Eye Health

Everyone's heard the old saying about how carrots help you see in the dark. But it is true that the foods you eat over the course of your life will directly impact the health of your eyes.

Further, as human life expectancy extends throughout the world, specific eye health problems like macular degeneration and cataracts will likely become far more common. Both conditions tend to run in my family, so it's particularly important to us here at Casual Kitchen to make sure we get a good mix of antioxidants and other nutrients critical for healthy vision.

I'm also lucky in that I have an expert on eye health living in my own home. And today I'm going to brazenly borrow from her and give you a list of the best foods to eat to protect your eyes over the long term.

The best foods for eye health can be loosely grouped into these four categories:1) sources of omega-3 fatty acids,
2) sources of antioxidants,
3) sources of lutein,
4) sources of flavonoids.

1) Omega-3 fatty acids:
Omega-3 fatty acids are essential fatty acids that the body needs for brain function as well as normal growth and development. Also known by the name polyunsaturated fatty acids, omega-3 fatty acids must be a part of your diet, because your body cannot create these fatty acids on its own.

Quite a few studies have indicated that people who consume more foods containing omega-3 fatty acids have less incidence of macular degeneration. Furthermore, omega-3 fatty acids help increase tear production and decrease chronic lid inflammation that causes dry eye.

So what should you eat to increase your intake of omega-3 fatty acids? Start with fish, especially fatty and energy-dense fish like tuna, salmon, trout and sardines. Nut oils, such as walnut oil, and other oils like olive oil, flaxseed oil or canola oil are all excellent sources. Even shellfish, such as shrimp, lobster, crab, oysters and clams, contain meaningful amounts of omega-3 fatty acids.

2) Antioxidants:
The term "antioxidant" is extremely broad, but in our case we're referring to foods rich in vitamin A, C and E, as well as foods rich in zinc and selenium. These antioxidants help prevent cataracts, help prevent damage to the retina, and also help prevent macular degeneration.

Furthermore, your body also needs Vitamin A for proper function of some of the basic mechanisms of the eye, such as your eye's photosensitive pigments. That saying about carrots and eyesight? It's actually true.

Most fruits, vegetables and juices are sources of a wide range of antioxidants. Fresh fruit, especially apples and citrus fruits, are particularly good sources. Cooked vegetables are also fine, but typically the cooking process will break down and/or remove some of the nutrients from the foods, which is why it's a good idea to include plenty of fresh and raw foods in your diet.

Note that some antioxidants, particularly fat-soluble ones like vitamin A and E, can be toxic in megadoses. This is less of a concern for water-soluble vitamins like vitamin C or B-complex vitamins which your body can easily excrete. Vitamin A and E, however, are stored in the body's fat tissue and are not that easily excreted.

This is one of those issues that will never happen to 99.999% of my readers, but I need to make the obligatory disclaimer just in case some knucklehead out there thinks that if one vitamin A supplement a day is good for him, 200 a day must be better. So, just know that, theoretically, fat-soluble vitamins like Vitamin A and E can be bad for you when taken in massive doses.

3) Lutein:
Doctors consider lutein an important antioxidant that is specifically useful for fending off macular degeneration. Lutein is one of the main pigments that make up the macula of the eye (this is the center of the retina responsible for your central and most detailed vision). Unfortunately, lutein tends to dissipate from the eye with age, which is why it's a great idea for people age 65 or older to include lutein supplements in their diets.

Lutein is found in dark leafy green veggies such as kale, swiss chard and collard greens, all of which you can find in your grocery store for laughably cheap prices. The most lutein-dense food available, however, is your basic raw spinach. But even run-of-the-mill vegetables such as corn and peas are good sources of lutein.

Again--just like with omega-3 fatty acids--your body can't make lutein on its own, so you must ingest it as part of your diet.

4) Flavonoids
Flavonoids are yet another class of antioxidants with wide benefits for human health. They have particular value in eye health, however, and are thought to be useful in protecting the eyes from macular degeneration and cataracts.

Green tea, red wine and dark colored berries (including blueberries, blackberries and dark cherries) are all excellent sources of flavonoids. Ginkgo biloba is yet another source of flavonoids. And of course, let's not forget the most important (to me at least) source of flavonoids: dark chocolate.

Scientists are still getting their arms around how exactly flavonoids actually work. Some recent studies have shown that they work in a counterintuitive way--it's the process by which your body removes the flavonoids from your body that help it gear up to remove other toxins and carcinogens roving around in your body. In fact it's quite difficult for the body to absorb flavonoids, and your body does not need large doses of flavonoids in order to obtain the proper health benefits from ingesting them.

Oh well: there goes my excuse for massive daily megadoses of dark chocolate.

Don't forget: you've gotta eat right to see right! If you eat a balanced diet that emphasizes foods containing all four of these categories of nutrients, you will be doing a lot to protect your eyes.

Next week, we'll talk about the worst dietary habits for your eyes.