Macular Degeneration: Blind from the Western Diet
Like other degenerative diseases � heart
disease, stroke, arthritis � age-related macular degeneration (AMD)
is due primarily to our diet and secondarily to our lifestyle � therefore
easily preventable, and to some extent reversible. This form of eye
disease is the leading cause of blindness in people age 64 or older living
in Western countries. The severe form with impairment of vision affects
1.7 million people in the United States, with 200,000 new cases annually.
Characteristically, this is a disease of progressive, painless, loss of
the central vision in the macula of both eyes simultaneously. The macula
is the part of the retina which provides our most acute and detailed
vision, and is used for visual activities, like reading, driving,
recognizing faces, watching television, and other fine work.
Multiple studies clearly show that the
same risk factors that predict the development and progression of coronary
artery disease (heart disease) also predict the chance of you losing your
eyesight from AMD:
* Overweight people have more than
twice the risk of progression of this disease from the mild form, which
affects nearly 8 million people in the United States, to the severe
blinding form over the next 5 years.1 Other common risk
factors shared by both diseases are cigarette smoking, lack of exercise,
high cholesterol, and hypertension.1
* A Diet high in all kinds fats,
including animal, trans-fats (margarines, shortenings), monounsaturated
fats (olive oil), and other vegetable fats, increases the risk of
developing AMD by two to three times compared to a diet low in fat.2,3
* A diet low in fruits and vegetables
is associated with an increased risk of AMD.4
* Vigorous physical
activity decreases the risk of AMD.1
* As people in
underdeveloped countries, for example Japan, Taiwan and China, switch from
their native diets based on starches (like rice) to Western diets their
risk of AMD increases parallel to their risk of heart disease.5
AMD is a Form of
Atherosclerosis from the Western Diet
Disease of the
arteries, known as atherosclerosis, is so common in Western
societies that it is considered a normal part of aging. However, this
disease is rare or unknown in parts of the world where people consume a
diet based on starches, vegetables and fruits. The underlying mechanism
involves the depositing of cholesterol and fat from the diet into the
walls of the arteries.6 In smaller vessels, such as in the eye,
this process results in stiffening of the walls, inflammation of the
vessels, a decrease in blood flow, and finally leakage of fluids through
the vessel walls into surrounding tissues. The average blood flow
reduction in people with AMD is 37% compared to people without this
disease.7 The end result is deprivation of oxygen and
nutrients to the visual tissues of the eye found in the retina and
concentrated in the macula � and the receptors of light and color (rods
and cones) soon become nonfunctional and die.
Preserving Your Sight
The commercial
solution to AMD is to take vitamin and mineral supplements. One recent
study found supplements containing vitamins C and E, beta carotene, and
zinc resulted in a 25% reduction in the risk of the intermediate stages of
AMD progressing to the advanced stages within 5 years.8
Despite this one study, a more honest conclusion is: in the face of
intensive marketing, high profits, doctors� recommendations, and
widespread use, no supplement has been found to be effective at preventing
AMD or delaying its complications.6 (A related story of
supplements failing heart disease patients is found in my August 2003
Newsletter article, �Plants, not Pills, for Vitamins and Minerals.�)
The simple,
cost-free, side-effect-free, non-profitable solution for preserving your
sight for a lifetime is the same one you should be presently using to
preserve the circulation to your heart, brain, kidneys, etc. � a healthy
low-fat, no-cholesterol diet, moderate exercise, and clean habits. As a
secondary therapeutic approach for some people with elevated blood
cholesterol levels (above 150 mg/dl), I recommend cholesterol-lowering
medications. (More information on this subject can be found in my
September 2002 newsletter article, �Cholesterol - When and How to Treat�
and my June 2003 Newsletter article �Cleaning out Your Arteries.�)
Even if you have
already started to lose your vision it is not too late. Treatment of
blood cholesterol and triglyceride levels has been shown to improve vision
in a person with very high levels of blood fat (triglycerides).9
Circulation to the eye and the rest of the body is improved immediately
after switching from a high-fat to a low-fat diet.10,11 The
underlying disease, atherosclerosis, is also reversible in time.12
Inflammation subsides and cholesterol and fat deposits are removed from
the artery walls. The damage left from meat- and dairy-laden forks and
spoons is the scarred tissue (sclerosis) that has forever lost its ability
to distinguish light. The sooner you make long overdue changes in your
diet the better sight you will have in your later years.
References:
1) Seddon JM.
Progression of age-related macular degeneration: association with body
mass index, waist circumference, and waist-hip ratio. Arch Ophthalmol.
2003 Jun;121(6):785-92.
2) Seddon JM.
Progression of age-related macular
degeneration: association with dietary fat, transunsaturated fat, nuts,
and fish intake. Arch Ophthalmol. 2003 Dec;121(12):1728-37.
3) Cho E.
Prospective study of dietary fat and the risk of age-related macular
degeneration. Am J Clin Nutr. 2001 Feb;73(2):209-18.
4) Mozaffarieh M.
The role of the carotenoids, lutein and zeaxanthin, in protecting against
age-related macular degeneration: A review based on controversial
evidence.
Nutr J. 2003 Dec 112:20-30.
5) Bird AC. What is
the future of research in age-related macular disease? Arch Ophthalmol.
1997 Oct;115(10):1311-3.
6) Friedman E. The
role of the atherosclerotic process in the pathogenesis of age-related
macular degeneration. Am J
Ophthalmol. 2000
Nov;130(5):658-63.
7) Grunwald JE.
Foveolar choroidal blood flow in
age-related macular degeneration.
Invest Ophthalmol Vis Sci. 1998 Feb;39(2):385-90.
8) Seddon JM.
Dietary carotenoids, vitamins A, C, and E, and advanced age-related
macular degeneration. Eye Disease Case-Control Study Group. JAMA.
1994 Nov 9;272(18):1413-20.
9) Nagra PK.
Lipemia retinalis associated with branch retinal vein occlusion.
Am J Ophthalmol. 2003 Apr;135(4):539-42.
10) Friedman M.
Serum Lipids and conjunctival circulation after fat ingestion in men
exhibiting type-A behavior pattern. Circulation 29:874 874-86,
1964.
11) Kuo P. The
effect of lipemia upon coronary and peripheral arterial circulation in
patients with essential hyperlipemia. Am J Med. 26:68, 1959.
12) Ornish D .
Intensive lifestyle changes for reversal of coronary heart disease.
JAMA. 1998 Dec 16;280(23):2001-7.
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