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Eye Health

National Eye Health Week: Taking Care of Our Eyes

National Eye Health Week: Taking Care of Our Eyes

The seventh annual National Eye Health Week begins on 19th September. The campaign’s aim is to promote the importance of eye health and help people to understand the best ways to look after their eyes.

According to the campaign organiser Vision Matters, sight is the sense people fear losing the most. While regular sight tests are widely understood to be one of the best ways to prevent sight loss, there are several other ways that we can protect eye health. Regular exercise can reduce the risk of sight loss by preventing high blood pressure and hardening of the arteries. Sun protective eyewear is also important to shield eyes from damaging UV rays.

Another important consideration is the effect of nutrition on eye health. Vision Matters emphasise the importance of a good diet in protecting eye health, especially as 60% of people living in the UK are unaware that our diet can affect the health of our eyes (1).

Low GI Diet

A good diet, full of low-GI, antioxidant-rich whole foods is crucial for eye health. Excess sugar in the blood can damage delicate eye tissues. Diets high in refined carbs such as white bread, white rice, and sugary treats have been linked to an increase in age-related macular degeneration (AMD) (2).

Degeneration of sight is also thought to be linked with diabetes. Sugar in the blood can damage the optic nerve at the back of the eye, as well as the lens at the front of the eye. Uncontrolled high blood sugar levels in diabetes can also affect the blood vessels supplying the eyes, eventually leading to blurred vision and sight loss.

Adopting a low-GI diet can be done with a few simple changes. Go for whole grains rather than refined grains and whole fruit rather than fruit juice. Concentrate on high fibre foods such as beans and vegetables and eat some protein with every meal, including breakfast.

Omega-3

Omega-3 fats are important for all-round eye health. They provide structural support to cell membranes and are also helpful for sufferers of dry eyes. Omega-3 fats are helpful in promoting proper drainage of intraocular fluid from the eye, and they also decrease the risk of glaucoma. Just one portion of oily fish per week has been found to reduce the risk of developing AMD by up to 40% (3).

The best sources are sardines, salmon and rainbow trout, as these oily fish are also low in mercury. Those who don’t like fish can obtain the omega-3 fat DHA from a good quality fish oil or algae supplement.

Antioxidants

Several clinical trials suggest that diets high in antioxidant nutrients are linked with lower rates of AMD (4).

By far the strongest evidence for the value in antioxidants in protecting eye health is for two nutrients called lutein and zeaxanthin. Lutein and zeaxanthin help your eyes to filter out UV light and also protect the macula (the centre of the retina) from damage.

In a study of more than 4000 adults, those who ate the most foods containing lutein and zeaxanthin had a 35% lower risk of developing AMD (5). Consequently, the researchers supported the use of lutein and zeaxanthin supplements in the prevention of AMD.

Top 10 Foods for Lutein & Zeaxanthin (per 100g):

Kale (raw) 39,550 mcg
Kale (cooked) 15,798 mcg
Spinach (raw) 15,798 mcg
Collards (cooked) 8,091 mcg
Spinach (cooked) 7,043 mcg
Lettuce (cos or romaine) 2,635 mcg
Broccoli (cooked) 2,226 mcg
Corn (cooked) 1,800 mcg
Peas (canned) 1,350 mcg
Brussels sprouts (cooked) 1,290 mcg

References
1. Eyecare Trust ‘Healthy Eyes Report’.
2. Mares JA and Moeller SM. Diet and age-related macular degeneration: expanding our view. Am J Clin Nutr 83:4 pp. 733-734.
3. van Leeuwen R, Boekhoorn S, Vingerling JR, et al. Dietary intake of antioxidants and risk of age-related macular degeneration. JAMA 2005;294:3101–7.
4. The Relationship of Dietary Carotenoid and Vitamin A, E, and C Intake With Age-Related Macular Degeneration in a Case-Control Study Archives of Ophthalmology September 2007, Vol. 125 No. 9.
5. Seddon JM, Cote J, Rosner B. Progression of age-related macular degeneration: association with dietary fat, transunsaturated fat, nuts, and fish intake. Arch Ophthalmol 2003;121:1728–37.

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High levels of vitamin D associated with reduced risk of developing early age-related macular degeneration

Age Related Macular Degeneration, or AMD, is the most common cause of blindness in people over the age of 50 in the UK.  Previously  I have written a lot about omega 3 fatty acids in relation to AMD, now a new study (1) published in the Archives of Ophthalmology has found that high levels of vitamin D in the bloodstream appear to be associated with a decreased risk of developing early age-related macular degeneration among women younger than 75 years.

Age Related Macular Degeneration
A new study published in the Archives of Ophthalmology has found that high levels of vitamin D in the bloodstream appear to be associated with a decreased risk of developing AMD (3).

To recap from previous posts: The macular is the light sensitive area in the centre of the retina that controls visual field and the ability to see colours.  AMD is caused by the deterioration of the macular.  As this happens the peripheral, outer, vision remains intact as the centre field of vision becomes slowly blurry, grey or filled with a large black spot.  Two forms of AMD exists: the dry form which develops slowly, accounting for 90% of all cases; and the wet form which causes rapid deterioration of central vision.

The exact causes of AMD are unknown although free radical damage, where unstable oxygen molecules damage the eye cells, is strongly implicated.  Tobacco smoke and sun exposure can increase the level of free radicals in the body and both are a risk for AMD.  High blood pressure and diabetes are also risk factors as these conditions can limit blood flow to the eyes.

The scientists (1) conducting this study wanted to look at the relationship between blood levels of vitamin D (serum 25-hydroxyvitamin D (25[OH]D)) and the prevalence of early age AMD in over 1000  women.   It is noted in the research paper that  “Serum 25(OH)D is the preferred biomarker for vitamin D status, as it reflects vitamin D exposure from both oral sources and sunlight.”  (1)

The initial (1) analysis found that no significant relationship was found between vitamin D status and early or advanced AMD.  However, when further analysis was done it was found that in the (968) women who were younger than 75 years old higher levels of serum vitamin D was associated with a significantly decreased risk of early AMD, in women 75 years and older (319), higher levels were associated with only a borderline statistically significant increased risk (1).

Doctors Best Best Vitamin D3 1000iu - 180 Softgels
It is likely that many people in the UK have low blood levels of vitamin D.

It was also found (1) that among women younger than 75 years, intake of vitamin D from foods and supplements was related to decreased risk of early AMD but no relationship was observed with self-reported time spent in direct sunlight.  Women who consumed the most vitamin D (from food and supplements) had a 59% decreased risk of developing early AMD compared with women who consumed the least vitamin D. The top food sources of vitamin D in the sample were milk, fish, fortified margarine and fortified cereal.  The authors conclude that (2)”This is the second study to present an association between AMD status and 25(OH)D, and our data support the previous observation that vitamin D status may potentially protect against development of AMD,” “More studies are needed to verify this association prospectively as well as to better understand the potential interaction between vitamin D status and genetic and lifestyle factors with respect to risk of early AMD.”

As stated this is just an association study and more research is needed before any firm conclusions can be drawn as to whether vitamin D can protect against the development of AMD.  As you can see from all my previous posts on vitamin D there is no set recommendation for daily supplement use and it is likely that many people in the UK have low blood levels of this important vitamin.  If you decide to take vitamin D supplements it is always best to check with your medical doctor first, especially if you are considering high doses (over 2000iu daily).

(1) Millen AE et al.  2011.  Vitamin D Status and Early Age-Related Macular Degeneration in Postmenopausal Women.  Archives of Ophthalmology.  129 (4): 481-489
(2) Press release.  JAMA and Archives Journals (2011, April 11). High levels of vitamin D appear to lower risk of age-related macular degeneration in young women. ScienceDaily. Retrieved April 12, 2011, from http://www.sciencedaily.com¬ /releases/2011/04/110411163817.htm

(3) Image courtesy of  Jeroen van Oostrom

Written by Ani Richardson

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