There is growing evidence for the benefits of supplementing zinc and lutein in those with signs of AMD. This issue of EduFacts explores the benefit of these nutrients beyond macular health.

Supplemental Zinc and Immunity

Many eye care professionals advise their patients with at least moderate AMD to take the high dose zinc and antioxidant combination found to slow vision loss and disease progression. In subsequent analyses, AREDS authors reported that subjects receiving zinc (alone or with antioxidants) had improved survival time from all causes (1). The positive association of zinc with increased longevity did not appear to be due to a reduction in deaths from circulatory disease or cancer. Instead, a possible protective effect for respiratory causes of death was observed. The authors noted that zinc's effect on mortality could be related to an improved immune response, which declines with aging. Results from a recent study lend credence to that postulation.

Fewer Infections, Less Oxidative Stress

Investigators from the University of Michigan and Wayne State University Medical School examined whether zinc supplements could improve immunity in fifty healthy seniors aged 55 to 87 (2). Zinc is essential to optimal immune function, and low plasma zinc is common in older individuals. At baseline, subjects had lower serum zinc and higher levels of oxidative stress compared to younger adults. Study participants received 45 mg of zinc or placebo daily for 1 year. The zinc group had significantly fewer infections (Table 3), lower oxidative stress markers, and reduced ex-vivo generation of pro-inflammatory cytokines (TNF-alpha) than placebo.

Lutein and Skin Health

In the controlled, year-long LAST trial, lutein was found to increase macular pigment density and improve measures of visual function such as glare recovery and near visual acuity in men with atrophic AMD (3). Since lutein filters potentially damaging UV light in the macula, scientists have theorized that lutein plays a similar protective role in the skin. Now, results of a double-blind trial from the University of Naples suggest that those taking supplemental lutein for ocular concerns might also derive a skin-protective effect (4).

Reduction in UV-Induced Skin Damage

One hundred twenty women with different skin types, but each exhibiting signs of premature aging, were followed for 12 weeks after assignment to one of four groups: A) oral placebo and topical placebo; B) oral placebo plus topical treatment with lutein and zeaxanthin; C) 10 mg of oral lutein with .06 mg zeaxanthin and topical placebo; or D) the oral supplement combined with topical lutein and zeaxanthin.

Photo-protection was calculated from skin surface redness after a 2 minute exposure to UV radiation on forearms and from susceptibility to sunburn, defined as the minimum erythematous dose. Photo-protection was increased in all the lutein and zeaxanthin treated groups (Fig). Oral supplements provided a 4-fold increase in protection, while the combined topical and oral intervention provided a 6-fold increase in photo-protection compared to controls. Surface lipids and skin hydration were significantly improved in all lutein-treated groups, while peroxidation of skin lipids decreased. Skin elasticity improved only in those topically treated.

Effect of Lutein and Zeaxanthin Upon Photoprotective Activity by Treatment Group Over the Study Period
* p < 0.05 vs. placebo treatment at the same week;
# p < 0.05 vs. the week 2 treatment value within the same treatment group.

References

1. AREDS Research Group. Associations of mortality with ocular disorders and an intervention of high-dose antioxidants and zinc in the Age-Related Eye Disease Study. AREDS Report No. 13. Arch Ophthalmol. 122:716-726, 2004.
2. Prasad AS, et al. Zinc supplementation decreases incidence of infections in the elderly: effect of zinc on generation of cytokines and oxidative stress. Am J Clin Nutr 85:837-44, 2007.
3. 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.
4. Palombo P, et al. Beneficial long-term effects of combined oral/topical antioxidant treatment with the carotenoids lutein and zeaxanthin on human skin. Skin Pharmacol and Physiol 20:199-210, 2007.