Zeaxanthin

Overview

Zeaxanthin is one of two carotenoids that occur at high levels in the retina of the eyes, the other being lutein. The greatest amounts of zeaxanthin occur in the macular region, whereas lutein is distributed throughout the entire retina. (1) These compounds are closely related and when they are found in plants, they both seem to occur together. For this reason, zeaxanthin and lutein are often discussed together, and in fact they are sometimes referred to as lutein-zeaxanthin. In one study, researchers reported that humans are capable of converting some lutein they have ingested into zeaxanthin. (2) These carotenoids have two main functions, they absorb the potentially harmful blue-violet wavelengths of light energy that come into the eye, and they also function as antioxidants.

Dosage Info

Dosage Range

1,000 mcg daily

Most Common Dosage

1,000 mcg daily

Dosage Forms

capsules and powder

Adult RDI

None established

Adult ODA

None established

Active Forms

Zeaxanthin

Absorption

Zeaxanthin is absorbed from the intestinal tract in humans. Since it is a lipid, absorption will be enhanced if it is taken with food that contains some oil or fat.

Toxicities & Precautions

General

Very safe. There are no reported toxicities, cautions, or contraindications with the use of zeaxanthin.

Functions in the Body

Antioxidant

Zeaxanthin functions as an antioxidant in the macular region of the eye, which means it is a compound that helps reduce damage to the lipid membranes from free radicals that are generated by ultraviolet light. (3)

Photoprotection

Zeaxanthin also absorbs the potentially toxic blue-violet wavelengths of visible light. This helps protect the eye from light-induced ultraviolet phototoxicity, which can cause free radical damage. (4)

Clinical Applications

Cataracts

Individuals whose diets provide greater amounts of dietary zeaxanthin and lutein have a reduced incidence of cataracts. In one study, men in the top 20% of zeaxanthin and lutein consumption had a 19% cataract risk reduction compared to men in the lowest 20% of zeaxanthin and lutein consumption. (5) Another study examined five different antioxidants and reported that lutein/zeaxanthin was the only antioxidant associated with nuclear cataracts. Individuals in the top quintile of lutein/zeaxanthin consumption were 50% less likely to develop a cataract compared to individuals in the lower quintile of consumption. (6)

Macular Degeneration

Studies support the theory that the carotenoids zeaxanthin and lutein provide a protective effect against the development of macular degeneration. In one study, the amount of zeaxanthin and lutein was determined in the retinas from 56 donors with age-related macular degeneration (AMD) compared to the level of these carotenoids in the retinas from 56 donors without AMD. The results revealed that retinas of individuals with macular degeneration had substantially lower levels of zeaxanthin and lutein than the controls who had not developed macular degeneration. Individuals in the top quintile of zeaxanthin and lutein levels were found to have an 82% lower risk of developing age-related macular degeneration compared to individuals in the bottom quintile. (7) Other sources report that individuals with greater consumption of zeaxanthin and lutein have a 40% reduced risk of developing age-related macular degeneration. (8) Although the estimated percentage of risk reduction differs (40% vs 82%), these studies both provide strong support for recommendations to consume more foods that are rich in zeaxanthin and lutein.

Recently the third National Health and Nutrition Examination Survey (NHANES) evaluated the relationship between dietary lutein and zeaxanthin and the presence of age-related maculopathy. No overall observations could be made regarding inverse relations between these carotenoids and age-related maculopathy. Pigment abnormalities are generally early signs of age-related maculopathy. An interesting find was that higher levels of lutein and zeaxanthin in the diet were associated with lower rates of pigmentary abnormalities. (9)

Symptoms and Causes of Deficiency

Since zeaxanthin is not an essential nutrient for humans, no deficiency condition has been identified.

Dietary Sources

Zeaxanthin occurs in a wide variety of dark-green and yellow colored fruits and vegetables. The highest concentrations are found in corn, collards, kale, spinach, broccoli, turnip greens, Swiss chard, persimmons, tangerines, oranges, and egg yolks. (10) , (11)

References

  1. View Abstract: Handelman GJ, Dratz EA, Reay CC, van Kuijk JG. Carotenoids in the human macula and whole retina. Invest Ophthalmol Vis Sci. Jun1988;29(6):850-5.
  2. View Abstract: Bone RA, Landrum JT, Friedes LM, et al. Distribution of lutein and zeaxanthin stereoisomers in the human retina. Experimental Eye Research. 1997;64:211-218.
  3. View Abstract: Sujak A, Gabrielska J, Grudzinski W, et al. Lutein and zeaxanthin as protectors of lipid membranes against oxidative damage: the structural aspects. Arch Biochem Biophys. Nov1999;371(2):301-7.
  4. View Abstract: Bernstein PS, Khachik F, Carvalho LS. Identification and quantitation of carotenoids and their metabolites in the tissues of the human eye. Exp Eye Res. Mar2001;72(3):215-23.
  5. View Abstract: Brown L, Rimm EB, Seddon JM, et al. A prospective study of carotenoid intake and risk of cataract extraction in US men. Am J Clin Nutr. Oct1999;70(4):517-24.
  6. View Abstract: Lyle BJ, Mares-Perlman JA, Klein BE, et al. Antioxidant intake and risk of incident age-related nuclear cataracts in the Beaver Dam Eye Study. Am J Epidemiol. May1999;149(9):801-9.
  7. View Abstract: Bone RA, Landrum JT, Mayne ST, et al. Macular pigment in donor eyes with and without AMD: a case-control study. Invest Ophthalmol Vis Sci. Jan2001;42(1):235-40.
  8. View Abstract: Moeller SM, Jacques PF, Blumberg JB. The potential role of dietary xanthophylls in cataract and age-related macular degeneration. J Am Coll Nutr. Oct2000;19(5 Suppl):522S-527S.
  9. View Abstract: Mares-Perlman JA, Fisher AI, Klein R, Palta M, Block G, Millen AE, Wright JD. Lutein and zeaxanthin in the diet and serum and their relation to age-related maculopathy in the third national health and nutrition examination survey. Am J Epidemiol. Mar2001;153(5):424-32.
  10. View Abstract: Sommerburg O, Keunen JE, Bird AC, van Kuijk FJ. Fruits and vegetables that are sources for lutein and zeaxanthin: the macular pigment in human eyes. Br J Ophthalmol. Aug1998;82(8):907-10.
  11. View Abstract: Handelman GJ, Nightingale ZD, Lichtenstein AH, Schaefer EJ, Blumberg JB. Lutein and zeaxanthin concentrations in plasma after dietary supplementation with egg yolk. Am J Clin Nutr. Aug1999;70(2):247-51.