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Ways a Poor Diet Can Cause Vision Loss


Vision loss resulting from a poor diet is not a theoretical possibility for medical students to ponder. The threat of vision loss from poor eating is not a far-fetched idea used by physicians and dietitians to get their patients to eat a nutritious diet. Vision loss from unhealthy diets is not restricted to developing nations where malnutrition is commonplace. Cases of vision loss related to poor diets have been recorded in the United States and the United Kingdom. Eating a well-balanced diet that’s rich in a wide variety of nutrients can prevent certain instances of vision loss.

Years of Eating a Junk Food Diet Cause Teen to Lose Eyesight

In September 2019, a 19-year old man in the United Kingdom made news around the world due to his blindness from poor nutrition. When the teen complained of hearing problems and diminished sight, doctors struggled to find the cause. It took years for physicians to discover the damage to the young man’s optic nerve was due to a vitamin B12 deficiency which in turn was the result of his poor eating.

For several years, he limited his diet to fries, processed ham, Pringles, sausage, and white bread. Today the youth’s visual acuity has declined to 20/200, the standard for being legally blind. Vision loss from nutritional optic neuropathy, the condition the teen has been diagnosed with, can be reversed when caught early. Unfortunately, the delayed diagnosis in this man’s case means the damage to his sight is permanent. Taking a vitamin B12 supplement kept his vision from getting worse, but he saw no improvement.

Seniors Suffer Vision Loss from Vitamin Deficiency

Vision loss from a vitamin B12 deficiency is not limited to young people. American physicians have reported cases of older people who have experienced vision loss from a lack of vitamin B12. In separate yet similar cases, a 63-year old man and a 68-year old man experienced vision loss from optic neuropathy due to a vitamin B12 deficiency. The vision of both men improved after receiving vitamin B12 supplements.

Plant-Based Diets Increase Your Risk of Vitamin B12 Deficiency

Almost all naturally occurring sources of vitamin B12 are in foods that vegans and many vegetarians avoid. Those sources include poultry, beef, dairy products, eggs, fish, and shellfish. Therefore, vegans and vegetarians have to be proactive to protect their sight and avoid vitamin B12 deficiency. A limited number of plant-based foods, such as certain cereals and some varieties of non-dairy milk, are fortified with nutrients including vitamin B12. It would be difficult to get a sufficient amount of vitamin B12 from fortified plant-based foods. To maintain vision and overall health, vegans and many vegetarians may need a vitamin B12 supplement.

A Poor Diet May Increase the Risk of Cataracts

Cataracts are a major cause of vision loss and blindness. Many research studies suggest a diet rich in nutrients such as Vitamin E, Vitamin C, B vitamins, lutein, and zeaxanthin may prevent cataracts. Conversely, a diet lacking a wide variety of fruits and vegetables probably does not provide the nutrients that could prevent cataracts. Good sources for the nutrients believed to prevent cataracts follow.

  • Vitamin E: Sunflower seeds, almonds, avocados, safflower oil
  • Vitamin C: Citrus fruits, watermelon, cantaloupe
  • B vitamins: Salmon, eggs, milk
  • Lutein and zeaxanthin: Spinach, kale, egg yolks, broccoli

A Healthy Diet May Prevent or Slow Macular Degeneration

In the U.S., age-related macular degeneration (AMD) is the leading cause of vision loss in people aged 65 and over. Eating a well-balanced diet may prevent or slow the progression of AMD. Regularly eating green, leafy vegetables may be particularly helpful in the prevention of AMD. Those vegetables are excellent sources of lutein and zeaxanthin. These two nutrients linked to cataract-prevention have also been connected to a lower incidence of AMD. Additional research suggests diets rich in lutein and zeaxanthin may slow the progression of the condition in AMD patients.

Lutein and zeaxanthin are not the only nutrients helpful for fighting or preventing macular degeneration. Tuna and salmon are high in the omega-3 fatty acids that may reduce the risk of AMD. Finally, adequate levels of zinc may also slow the progression of AMD. Good dietary sources of zinc include oysters, beef, pork, and milk. (Zinc is a critical nutrient for maintaining vision. Zinc deficiency is also associated with impaired night vision.)

In summary, vision loss is a potential outcome when a poor diet eliminates or extremely reduces the nutrients necessary for optimal eye health. Regularly consuming a wide variety of foods from all food groups offers protection from vision loss due to nutrient deficiencies. People who have limited diets such as vegans should consult a health professional about dietary supplements to prevent vision loss.