B vitamin supplement use curbs risk of age-related macular degeneration

Seeing and Believing

What’s the leading cause of blindness in people who are age 50 and older?

I believe most HSI members know the answer to this one: Age-related macular degeneration (AMD).

In AMD, a blur or dark spot appears at the center of the field of vision. The spot eventually expands over years until only peripheral vision remains. By some estimates, almost two million AMD patients in the U.S. are in the advanced stage of the disease.

Today we’ll look at several ways to minimize your AMD risk. And if you already have AMD, I’ll tell you how you might slow and even stop your progressive vision loss.

No miracles…just blindness prevention

We’ll start at Harvard Medical School, where researchers found that B vitamin supplements failed miserably in preventing cardiovascular events.

That sounds discouraging until you find out that all 5,442 of the women recruited for the study had heart disease or at least three heart disease risk factors. B vitamins have been shown to support heart health, but saving heart disease patients from heart attacks and other adverse heart events is a very tall order.

Because B vitamins lower homocysteine (an amino acid that promotes plaque buildup in the arteries), and because a high homocysteine level is a risk factor for AMD, the Harvard team switched gears to assess the effects of B vitamin supplementation on more than 5,200 women who participated in the study who had not been diagnosed with AMD at baseline.

These women were randomly chosen to receive either placebo, or three B vitamins: 2.5 mg per day of folic acid, 50 mg per day of vitamin B6, and 1 mg per day of vitamin B12. Intervention lasted a little over seven years.

Results:

55 cases of AMD were reported in the B vitamin group
82 cases of AMD were reported in the placebo group
26 cases of visually significant AMD were reported in the B group
44 cases of visually significant AMD were reported in the placebo group

Dr. William Christen, the lead author of the study, told the Associated Press that this B vitamin advantage over AMD probably also applies to men.

Just add fish, fruits, and vegetables

This Harvard study is no doubt the longest and largest trial to test a non-drug therapy in the prevention of AMD. But in previous e-Alerts I’ve told you about other important research that can help us plan strategies to avoid this dreaded disease.

In the e-Alert “Influence By the Numbers” (6/24/08), I told you about a meta-analysis in which Australian researchers collected data from nine studies. They found that subjects who ate fish two times each week significantly reduced their risk of early AMD, and even the more advanced and dangerous late form of the disease. This analysis included nearly 89,000 subjects, and more than 3,200 AMD patients.

And in the e-Alert “From L to Z” (4/12/07), I looked at a study in which dietary records for more than 1,700 women over the age of 50 were followed for 15 years. Results showed that AMD risk was cut by more than 40 percent among the women who had a steady intake of lutein and zeaxanthin – antioxidant-rich carotenoids found in egg yolks and colorful fruits and vegetables such as orange pepper, kiwifruit, squash, mango, honeydew, and broccoli.

And in 2002 I told you about National Eye Institute (NEI) study in which researchers tracked nearly 3,600 participants between the ages of 55 and 80 for more than eight years to examine the effect of antioxidant supplement intake on AMD. Results showed that when administered in the early stage of AMD, certain supplements significantly reduced predicted vision loss.

The NEI team recommended that anyone at risk of developing AMD should consider taking these supplements daily, in the same amounts used in the study:

Vitamin C – 500 mg
Vitamin E – 400 IU
Beta-Carotene – 15 mg
Zinc (as zinc oxide) – 80 mg
Copper (as cupric oxide) – 2 mg

Talk to your doctor about AMD and supplement intake before adding new supplements to your daily regimen.

Sources:
“Folic Acid, Pyridoxine, and Cyanocobalamin Combination Treatments and Age-Related Macular Degeneration in Women” Archives of Internal Medicine, Vol. 169, No. 4, 2/23/09, archinte.ama-assn.org
“Study: Taking B Vitamins Can Prevent Vision Loss” Carla K. Johnson, Associated Press, 2/23/09, ap.org