Thursday, July 12, 2018

Eye Health: Age-Related Macular Degeneration (AMD) Prevention

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In the aging human eye, oxidative damage and accumulation of pro-oxidant lysosomal lipofuscin cause functional decline of the retinal pigment epithelium (RPE), which contributes to age-related macular degeneration.
There’s a known decline in the of RPE cell function in age-related macular degeneration. These are the photoreceptor support cells in the retina that are critical for the process of light into sight conversion. The RPE dysfunction is caused by:[11]  
  • A build-up of metabolic waste products in the RPE called lipofuscin.
  • An RPE oxidation burden that compromises important metabolic pathways.
The ensuing dysfunction, distress and sometimes death of the RPE cells results in age related macular degeneration.
However, researchers believe that the real causes of MD could be multifactorial:
  • Hereditary or genetic predisposition
  • Environmental
  • Nutritional
But, age is the strongest known risk factor and the disease is more likely to occur after the age of 50.[1]

Video 1.  Dietary Prevention of Age-Related Macular Degeneration (YouTube link)

How to Prevent MD?

There is currently no cure for the disease.[1]  The good news is if you are predisposed genetically to AMD, you can take steps to lower your risk of developing the condition, says ophthalmologist Rishi Singh, MD.

To prevent MD, you can try:
  • Stop smoking if you're a smoker.
  • Eat a well-balanced diet with foods rich in a source of antioxidants  and carotenoids
    • Carotenoids 
      • Carotenoids protect eyes against age-related macular degeneration and also provide very mild sun protection, equal to about an SPF of 3.
      • Lutein is a pigment in the macula that along with another pigment (Zeaxanthin), is believed to protect the macula from damaging effects of blue light.[12] 
      • Lutein and zeaxanthin are present in green leafy vegetables (e.g., spinach and kale) and corn.
      • Within the central macula, zeaxanthin is the dominant component, whereas in the peripheral retina, lutein predominates.
      • Lutein /zeaxanthin can decrease the risk for cataracts, macular degeneration, and the development of atherosclerotic plaques
      • Carrots, sweet potatoes and pumpkins, which are high in beta carotene, which converts to Vitamin A
      • Fats improve the absorption of lutein and zeaxanthin, so including them in your diet, such as some olive oil in a green salad or some butter or coconut oil with your cooked greens, is a good idea.[9]
    • Antioxidants
      • Papaya, oranges and grapefruit, which are top sources of Vitamin C
      • Eat Goji berries with nuts and seeds (see above video)
      • Flavonoids in oranges
        • Associate Professor Bamini Gopinath from the University of Sydney said the data showed that flavonoids in oranges appear to help prevent against MD.[1]



  • Take omega-3 fatty acids
  • Wear sunglasses (especially at the time of skiing)
    • UVA and UVB rays from the sun can cause oxidative stress and contribute to AMD, so it’s crucial to wear sunglasses that protect against ultraviolet light.
  • Maintain normal blood pressure
  • Maintain normal body weight
    • Exercise regularly
    • Central obesity causes inflammation
  • Use of the supplements with that of AREDS (or the Age-Related Eye Disease Study) formulation daily
    • AREDS recommends:
      • 500 mg Vitamin C
      • 400 IU Vitamin E
      • 15 mg Beta Carotene
      • 80 mg Zinc
      • 2mg Copper
    • Note that AREDS supplements is not a cure for MD; rather it is a treatment that helps to prevent progression and visual loss.
    • You should consult your eye care provider before taking AREDS supplements (especially if you are a current or recent smoker).

References
  1. An orange a day keeps macular degeneration away: 15-year study
  2. 100 Questions & Answers About Macular Degeneration by Jeffrey S. Heier, MD
  3. The Language of Life by Francis S. Collins 
  4. Avocado 101
  5. What are the warning signs of macular degeneration?
  6. Your Lifestyle May Increase Your Risk of Age-Related Vision Loss (Cleveland Clinic) 
  7. Cataracts and Macular Degeneration
  8. Optometrist or Ophthalmologist: Which Is Best for Your Eye Care?
    • “Optometrists can handle nearly all the medical aspects of ophthalmology. But they do not perform surgery,” Dr. Wagenberg explains.
  9. Lutein, Zeaxanthin, and meso-Zeaxanthin: The Basic and Clinical Science Underlying Carotenoid-based Nutritional Interventions against Ocular Disease
  10. Dietary antioxidants prevent age-related retinal pigment epithelium actin damage and blindness in mice lacking αvβ5 integrin
  11. Eating Grapes Can Help to Prevent Macular Degeneration
  12. Chronic blue light leads to accelerated aging in Drosophila by impairing energy metabolism and neurotransmitter levels