SBH Rep contact request

"Benchmark" Findings from New Lutein, Vitamin C Studies

New Study Shows Lutein Improves Eyesight for AMD Patients

The Lutein Antioxidant Supplement Trial (LAST) is the first study to report actual improvement in key visual functions among patients who already have "dry" age-related macular degeneration (AMD), the most common form of this disease. Prior to the publication of LAST in April (1), studies had linked greater consumption of lutein solely to a lower risk of AMD in healthy people.

This double-blind, year long study looked at the effects of 10 mg of lutein alone or combined with other antioxidants, on a number of visual measures in 90 patients with atrophic AMD. The amount of lutein supplemented in LAST is equivalent to eating about 3-4 ounces of spinach each day. While lutein is concentrated in dark green leafy vegetables such as spinach, collards and kale, the U.S. intake is estimated to be only 1-2 mg daily.

Compared to those getting a placebo, the lutein/antioxidant supplemented group experienced a 50% increase in macular pigment density, indicating an improved ability to filter out damaging UV light. Patients taking lutein or the combination showed improvement in quality of vision (measured by contrast sensitivity) and glare recovery, a test of macular function. They were also better able to distinguish near object details and shape (near visual acuity). According to lead author Dr. Stuart Richer, patients taking lutein were able to see the equivalent of one line more on standard eye tests at the end of the year, while those receiving placebo continued to decline-- a clinically meaningful finding for those trying to preserve their vision.

Vitamin C Fights Inflammation-Risk Factor for Heart Attack

A second study published in April is also a "first" of its kind--the first to report that vitamin C can lower C-reactive protein (CRP). CRP is a biomarker for inflammation that has garnered increasing attention as a new way to identify those at risk for heart attack (2). It's now understood that chronic inflammation can lead to heart attack and stroke by making cholesterol-laden artery plaque less stable and more likely to rupture (See newsletter issues for March & April, 2004).

CRP levels can rise up to a 100 fold for short periods during illness, because inflammation occurs as part of the body's normal defense against infection. However a persistent, moderately elevated level of CRP in the blood reflects chronic inflammation, and has been linked to increased risk of heart disease, diabetes, Alzheimer's disease, and even age-related macular degeneration.

In this double-blind study, researchers at University of California at Berkeley tested 160 healthy adults who either smoked or were exposed to second hand smoke. Those who had greatly elevated CRP likely due to existing illness were excluded from the study. The remaining participants were assigned to receive placebo, 500 mg of vitamin C, or a mixture of antioxidants (C, E and alpha-lipoic acid). Plasma levels of CRP in the volunteers were measured before and at the end of the two month trial.

Levels of CRP decreased a significant 24% among those supplementing with vitamin C compared to placebo takers. CRP levels also declined for those taking the antioxidant mixture, but not as much as vitamin C group. The researchers noted that much higher levels of vitamin E than were utilized in this study have previously been reported to lower CRP in diabetics and healthy individuals (3). These same investigators will be conducting a second trial in an attempt to replicate these findings. According to lead author Dr. Gladys Block, "If our finding of vitamin C's ability to lower CRP is confirmed, vitamin C could become an important public health intervention."

References

1. Richer S, et al. Double-masked, placebo-controlled, randomized trial of lutein and antioxidant supplementation in the intervention of atrophic age-related macular degeneration: the Veterans LAST study (Lutein Antioxidant Supplementation Trial). Optometry 75:216-30, 2004.
2. Block G, et al. Plasma C-reactive protein concentrations in active and passive smokers: influence of antioxidant supplementation. J Am Coll Nutr 23:141-47, 2004.
3. Devaraj S, et al. Alpha tocopherol supplementation decreases serum C-reactive protein and monocyte interleukin-6 levels in normal volunteers and type 2 diabetic patients. Free Rad Biol Med 29:790-92, 2000.