Excerpted from page 42 of the June 2017 edition of AOA Focus.
With an alphabet soup of dietary crazes and concerns, from gluten-free to paleo to vegan, it's not always easy for doctors of optometry to advise patients on how what they eat can impact their eyes. Dietary changes can affect your health both positively and negatively, depending on what's going into the body—and what isn't, says Cecelia Koetting, O.D., of Norfolk, Virginia.
"All diets or eating habits can be done correctly or incorrectly," Dr. Koetting says. "Knowing what you're eating, what your body needs and how to make sure it's in the diet is the important thing."
As our culture grows increasingly health conscious—more so than prior generations—we're focusing on maintaining our bodies, especially as we live longer, Dr. Koetting says. "We're also becoming more aware of different nutrients and chemicals we're putting into our bodies and how they affect our eyes."
Dr. Koetting teaches continuing education that explores ocular considerations of diets, including gluten-free, paleo and vegan, as well as issues around dietary supplements. Here are the highlights:
Vegetarian and vegan
While vegetarians cut meat from their diets, vegans eschew all animal products, including eggs and dairy. Ensuring vegetarians, and especially vegans, are getting enough of some of the key vitamins for eye health can be tricky, Dr. Koetting says. For instance, the essential fatty acids, Omega-3 and Omega-6, which aid visual development and retinal function, are most prevalent in eggs and freshwater fish. Even the alternative, fish oil supplements, might be off limits because they contain an animal product. Nuts and seeds contain some of these essential fatty acids, but not as much as animal products.
The paleo diet centers on one question: What would a caveman eat? People on the paleo diet eat mainly raw foods, such as fruits, vegetables and nuts, as well as unprocessed meat and seafood. They avoid canned food and limit dairy. But as long as people on the paleo diet eat a variety—not just meat—their eye health should be unaffected, Dr. Koetting says.
Celiac disease and gluten sensitivity
People with celiac disease experience an immune response, typically diarrhea, when they eat gluten. Those with gluten sensitivity also might experience intestinal distress and inflammation.
Fortunately, avoiding gluten doesn't seem to have any harmful effects on eye health, Dr. Koetting says.
Irritable bowel syndrome
People with irritable bowel syndrome (IBS) experience inflammation when they stray from the diets that work best for them, Dr. Koetting says, so avoiding foods that irritate them also will keep the eyes healthy. In fact, IBS flare-ups can sometimes cause iritis.
People with diabetes sometimes develop eye—related complications, the most notable being diabetic retinopathy. For patients with diabetes, Dr. Koetting says, their eye health depends on their ability to stick to their diet and control their blood sugar.
Organic foods are produced without the use of pesticides, synthetic fertilizers, antibiotics and other additives. The fruits and vegetables that retain the most water, such as strawberries, spinach and apples, are particularly susceptible to these chemicals. While there are many reasons to avoid these additives, Dr. Koetting says, the benefits are more for our body overall than our eyes specifically.
Vitamins and dietary supplements
When it's impossible to get all the vitamins and nutrients you need from food, Dr. Koetting says, supplements might be the answer. Here are some key vitamins and their effects on the eyes:
- Alpha Lipoic Acid: Found in red meat, organ meat, and brewer's yeast, alpha lipoic acid can prevent certain types of cell damage and restore vitamin levels.
- Vitamin C: Eating fruits and vegetables containing vitamin C will yield benefits such as lower risk of cataract formation.
- Lutein and Zeaxanthin: These reduce the risk of chronic eye disease and filter harmful blue light, and are contained in eggs and green, leafy vegetables.
- Zinc: Found in oysters, red meat, poultry, beans, nuts, dairy and fortified cereal, zinc aids in retinal melanin production.
Dr. Koetting says her take-home message is simple: "Know what you're putting into your body, whether it be the food that you're about to consume or if you're going to take a vitamin."
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