Recent Macular Degeneration Research – Part 2

macular degenerationScientists are putting significant focus on Age-Related Macular Degeneration in their research. This eye disease strikes mostly older adults, over aged 50. The “Baby Boomer” generation is well above age 50, as are their living parents. Understanding the causes and potential treatments for Macular Denegation (ARMD) are important, because vision-impaired elderly people need extra help with their daily activities. Also, quality of life is lowered when vision is poor.

The macula is a tiny yellowish spot in the back of the eye, on the retina. It allows for central vision. Central vision is possible because of the macula. If it breaks down, reading, writing, watching TV, cooking, driving and even facial recognition are impaired. Macular Degeneration is degenerative, meaning that it gets worse over time.

ARMD comes in two forms. The more common “dry” macular degeneration is caused by little, fatty deposits that form on the macula. These “drusens” damage the cells of the macular. Only 10% have the “wet” form, which is often an advanced form of the “dry” version. Also called choroidal neovascularization, wet AMD involves the creation of new blood vessels. Untreated, the rate of deterioration of vision speeds up.

Our recent article Recent Macular Degeneration Research: Part 1 included standard treatment and support, nutritional support, and research into: low vision aids, laser therapy, Microcurrent Stimulation, Lutein, Zeaxanthin, Mesozeathin, Vitamin D3, Omega-3 Fatty Acids, and Astaxanthin. In this article, we will cover AMD and:

  • Genetics
  • Smoking and Macular Degeneration
  • Exercise
  • The Mediterranean diet
  • Bilberry
  • Green Tea

Genetics and Macular Degeneration

Genes are believed to play a role in an individual’s susceptibility to Macular Degeneration. One study focused on variations in the parts of the DNA that create HLA (human leukocyte antigen)1, which is involved immunity and inflammation. The study used a large number of both AMD patients (4,841) and controls (23,790) in order to reproduce prior, but smaller, studies. The researchers found a relationship between certain types of HLA sequences and an increased risk of developing AMD.2

DNA is not destiny – lifestyle factors and nutrition likely combine with genetics to cause this disease. A study of older women gave them “healthy lifestyle scores” based on nutrition, exercise, and smoking habits. The subjects with a high genetic likelihood of developing AMD and a low healthy lifestyle score were 3.3 times more likely to get AMD than those with high genetic risk with better lifestyles. Interestingly, unhealthy lifestyles increased the risk of developing AMD, regardless of any known genetic risk

Smoking

Smokers are four times more likely to develop macular degeneration3. The deleterious effects of smoking tobacco are widespread, and the eyes are not exempt from its oxidizing effects.

A study examined DNA damage in the macula of smokers4 They measured the oxidative stress in the macula’s pigmented layers, and found it to be at high levels. There was increased genetic damage in the Bruch’s membrane and the choroidal stroma in the retina. Inflammation was indicated by significantly high levels of C-reactive protein.

An especially risky combination is a poor diet and smoking5. The diet should include plenty of carotenoids. The most important carotenoids for eye health are lutein (found in leafy green vegetables, corn, Brussels sprouts, broccoli, & eggs), astaxanthin (from pink seafood) and zeaxanthin (from orange food, leafy greens, peas and kiwi).

Smoking cigarettes and drinking alcohol may contribute to a “serious oxidative imbalance and DNA damage” in AMD, making the disease worse.6

Exercise

Humans were made to move. We cannot maintain optimal health sitting at a desk, in a vehicle and in front of a screen all day. The health of the eye reflects the overall health of the system. Countless studies have shown regular exercise is the cornerstone of any wellness program. A sedentary lifestyle is a risk factor for countless diseases, Alzheimer’s disease to cancer to diabetes to vision problems.

The first specific study of amount of exercise (“daily movement patterns”) among US adults with Macular Degeneration was completed recently.7 The 1,656 participatnts wore accelerometers for a week. Each had either no AMD, early AMD, or late AMD. Those with AMD did half the amount of moderate-to-vigorous physical activity compared to those with no AMD. This is partially explained by less visual acuity.

Older mice exercised regularly on treadmills.8 Their retinas were in significantly better condition than sedentary mice of the same age. The difference was attributed to reduced retinal oxidative stress.

Some studies did not find a specific correlation between AMD and exercise. A medium-term study9 found that the most active adults over age 74 had 79% less late AMD than sedentary participants. Adjusting for other factors like BMI, smoking, fish consumption and white cell count, however, found no correlation. They were also unable to find significant associations in participants under age 75.

A large study of more than 20,000 Australians looked at past exercise habits.10 Women who did frequent vigorous exercise — 3 or more times per week — had a 22% less chance of developing intermediate AMD.

The Mediterranean Diet

More than a fad, the Mediterranean diet has been consumed for centuries by populations near the Mediterranean Sea, including the Greeks. Vegetables, fruits, legumes, whole grains and nuts and seeds are the majority of diet. Sweets and animal products like fish, seafood, poultry, red meat, eggs and dairy products are eaten in small amounts. Beverages include water and moderate amounts of wine.

A Mediterranean diet study11 found that if the individual was not at a high genetic risk for AMD, following the Mediterranean diet reduced their risk of developing the disease.

Bilberry

Nicknamed “the vision herb,” bilberry increases eye circulation, helps keep the capillaries intact, and helps stimulate rhodopsin, which is necessary for seeing at night. Its antioxidants promote tissue health and strengthen collagen. “Athocyanosides” are the active ingredients in bilberry. A 2005 study12 found neither macular degeneration nor cataracts in mice who were given bilberry as part of their diets.

Green Tea

Green Tea is high in antioxidants called catechins including vitamin C, vitamin E, lutein, and zeaxanthin, helping to protect the delicate tissues in the retina. For example, a 2014 study13 showed how green tea polyphenol epigallocatechin gallate (EGCG) protected eye cells in animals from oxidative damage induced by hydrogen peroxide.

Many risk factors for Age-Related Macular Degeneration can be mitigated with sufficient exercise, proper nutrition, and not smoking. Even people with a high genetic risk of developing macular degeneration can swing the odds in their favor with a healthy lifestyle.

  1. Common coding variants in the HLA-DQB1 region confer susceptibility to age-related macular degeneration. Jorgenson E. et. al. European Journal of Human Genetics. 2016 Jan 6. doi: 10.1038/ejhg.2015.247. Epub ahead of print
  2. Joint Associations of Diet, Lifestyle, and Genes with Age-Related Macular Degeneration. By Meyers KJ et. al. Ophthalmology. 2015 Nov;122(11):2286-94. doi: 10.1016/j.ophtha.2015.07.029. Epub 2015 Sep 6.
  3. Smoking quadruples risk for vision-stealing eye disease, CNN Medical Unit, Daily Dose, 12/22/08
  4. Assessment of Proteins Associated With Complement Activation and Inflammation in Maculae of Human Donors Homozygous Risk at Chromosome 1 CFH-to-F13B, Keenan T.D. et. al. Investigative Opthalmology and Visual Science, July, 2015.
  5. Dietary carotenoids, vitamins A, C, and E, and advanced age-related macular degeneration. Eye Disease Case-Control Study Group. Seddon JM et. al. JAMA. 1994 Nov 9;272(18):1413-20.
  6. Combined effects of cigarette smoking and alcohol consumption on antioxidant/oxidant balance in age-related macular degeneration. Venza et. al. Aging Clin Exp Res. 2012 Oct;24(5):530-6. doi: 10.3275/8477. Epub 2012 Jun 25.
  7. Age-Related Macular Degeneration Is Associated with Less Physical Activity among US Adults: Cross-Sectional Study. Loprinzi PD et. al. PLoS One. 2015 May 1;10(5):e0125394. doi: 10.1371/journal.pone.0125394. eCollection 2015.
  8. Treadmill Exercise Attenuates Retinal Oxidative Stress in Naturally-Aged Mice: An Immunohistochemical Study. Kim CS et. al. Int J Mol Sci. 2015 Sep 2;16(9):21008-20. doi: 10.3390/ijms160921008
  9. Invest Ophthalmol Vis Sci. 2014 Nov 11;55(12):7799-803. doi: 10.1167/iovs.14-15575. Physical activity and the 15-year incidence of age-related macular degeneration. Gopinath B et. al.
  10. Br J Ophthalmol. 2016 Jan 19. pii: bjophthalmol-2015-307663. doi: 10.1136/bjophthalmol-2015-307663. (Epub ahead of print) Past physical activity and age-related macular degeneration: the Melbourne Collaborative Cohort Study. McGuinness MB et. al.
  11. Adherence to a Mediterranean diet, genetic susceptibility, and progression to advanced macular degeneration: a prospective cohort study. Benedicte M.J. Merle, et al. American Journal of Clinical Nutrition, November, 2015
  12. Dietary supplementation with bilberry extract prevents macular degeneration and cataracts in senesce-accelerated OXYS rats” by Fursova AZ et. al., Adv Gerontol. 2005;16:76-9.
  13. Epigallocatechin gallate (EGCG) prevents H2O2-induced oxidative stress in primary rat retinal pigment epithelial cells. Cia D et. al. Curr Eye Res. 2014 Sep;39(9):944-52. doi: 10.3109/02713683.2014.885532. Epub 2014 Feb 21.
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Recent Macular Degeneration Research - Part 2
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Recent Macular Degeneration research on genetics, smoking and Macular Degeneration, exercise, the Mediterranean Diet, bilberry and green tea. Part 2 in a series.
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