Tuesday, September 22, 2009

Lutein & Zeaxanthin

Overview

Lutein and zeaxanthin are carotenoids found in highest concentrations in the macular region of the eyes (the back of the eye where the retina is located), where they are believed to help filter out damaging blue light and prevent free radical damage to the delicate structures in the back of the eye. Dietary supplements containing lutein and zeaxanthin are commonly recommended to help prevent age-related macular degeneration (ARMD) and the development of glaucoma and cataracts.


Because antioxidants can provide increased protection against the oxidizing ultraviolet radiation of the sun, anybody that spends time outdoors exposed to the sun should be concerned with the potential for ultraviolet radiation to damage eye health and impact vision. Lutein and zeaxanthin are the only carotenoids that become concentrated in the retinal region of the eye – known as the macula. High dietary intake of lutein-rich fruits and vegetables (yellow and dark green) has been associated with a significant reduction in macular degeneration – the leading cause of blindness in Americans over the age of 65.


Comments

Dietary supplements containing lutein and zeaxanthin are available from a number of manufacturers as an alternative for those people not able or willing to increase their consumption of brightly colored fruits and vegetables. When choosing a supplement, be sure to select one that delivers an effective level of lutein (about 4-6mg/day). Lutein is now being added to national brands of multi-vitamins – but most provide only 250 micrograms (mcg) or less of lutein – or more than 20 times less than the levels shown to be effective in preventing ARMD and even several times below levels that could reasonably be achieved in the diet from a high-intake of fruits and vegetables.


Scientific Support

Lutein and zeaxanthin are yellow pigments found in high concentrations in egg yolks, yellow fruits and vegetables as well as in dark green, leafy vegetables. In particular, spinach, kale and collard greens contain high levels of these two carotenoids – and numerous dietary survey studies (Castenmiller et al. 1999, Sommerburg et al. 1998) have shown that those individuals with the highest spinach consumption (a rich source of lutein) have the lowest risk of developing ARMD (reductions of as much as 90% in some cases).


Both lutein and zeaxanthin seem to reduce the risk of ARMD and protect overall eye health by at least two different routes. First, both of these carotenoids are absorbed from the diet into the circulation and eventually concentrate specifically in the eye (in the macular region of the retina). It is interesting to note that lutein and zeaxanthin are the only carotenoids known to concentrate specifically in the eye tissues. The high levels of these carotenoids in the eye serve to protect tissues by minimizing free radical damage and by absorbing damaging blue light rays (Landrum et al. 1997)).


It is thought that a low macular pigment density may increase the risk ARMD and cataracts by allowing more damage from blue light (Sommerburg et al. 1999). Several observational studies have shown that high dietary intakes of lutein and zeaxanthin (from spinach, broccoli and eggs) are associated with a significant 20% reduction in the risk for cataracts (Moeller et al. 2000) and approximately 40% for age-related macular degeneration (Bartlett and Esperjesi 2003, Mozaffarieth et al. 2003). Studies have shown that dietary supplementation with lutein (30mg/day for 140 days) elevates serum lutein levels by 10 times, increases macular pigment density by 20-40% and reduces transmission of blue light to the eye’s photoreceptors by 30-40% (Hammond et al. 1997, Johnson et al. 2000). Other studies have shown that daily egg yolk consumption can increase plasma levels of lutein by 28-50% and zeaxanthin by 114-142%. Multi-center clinical studies of patients with advanced ARMD (age range 55-80 years) have found the risk for ARMD to be reduced by over 40% by a high dietary intake of carotenoids (Pratt 1999). In particular, both lutein and zeaxanthin were strongly associated with a reduced risk for macular degeneration (Seddon et al. 1994).


Safety / Dosage

There are no known adverse side effects associated with dietary supplements containing lutein or zeaxanthin when used at recommended levels. Most supplements should be taken with a meal to lessen he chance of causing stomach upset and to increase their digestion and absorption (bioavailability). From studies of ARMD rates and dietary intake, it appears that diets providing about 6 milligrams (mg) of lutein per day can reduce ARMD prevalence by nearly half. Eating more of the carotenoid-rich foods mentioned above should be the first step to increase lutein intake. Unfortunately, recent diet surveys have indicated that consumption of these foods has dropped more than 20% in the two groups at highest risk for ARMD (women and elderly). As many carotenoids are rapidly cleared from the body, it is logical to consider splitting daily intake into two doses (3mg with breakfast and 3mg with dinner).


References

1.Alves-Rodrigues A, Shao A. The science behind lutein. Toxicol Lett. 2004 Apr 15;150(1):57-83.

2.Bartlett H, Eperjesi F. Age-related macular degeneration and nutritional supplementation: a review of randomised controlled trials. Ophthalmic Physiol Opt. 2003 Sep;23(5):383-99.

3.Beatty S, Nolan J, Kavanagh H, O'Donovan O. Macular pigment optical density and its relationship with serum and dietary levels of lutein and zeaxanthin. Arch Biochem Biophys. 2004 Oct 1;430(1):70-6.

4.Blodi BA. Nutritional supplements in the prevention of age-related macular degeneration. Insight. 2004 Jan-Mar;29(1):15-6; quiz 17-8.

5.Bone RA, Landrum JT, Dixon Z, Chen Y, Llerena CM. Lutein and zeaxanthin in the eyes, serum and diet of human subjects. Exp Eye Res. 2000 Sep;71(3):239-45.

6.Bone RA, Landrum JT, Friedes LM, Gomez CM, Kilburn MD, Menendez E, Vidal I, Wang W. Distribution of lutein and zeaxanthin stereoisomers in the human retina. Exp Eye Res. 1997 Feb;64(2):211-8.

7.Castenmiller JJ, West CE, Linssen JP, van het Hof KH, Voragen AG. The food matrix of spinach is a limiting factor in determining the bioavailability of beta-carotene and to a lesser extent of lutein in humans. J Nutr. 1999 Feb;129(2):349-55.

8.Davies NP, Morland AB. Macular pigments: their characteristics and putative role. Prog Retin Eye Res. 2004 Sep;23(5):533-59.

9.Granado F, Olmedilla B, Blanco I. Nutritional and clinical relevance of lutein in human health. Br J Nutr. 2003 Sep;90(3):487-502.

10.Gruber M, Chappell R, Millen A, LaRowe T, Moeller SM, Iannaccone A, Kritchevsky SB, Mares J. Correlates of serum lutein + zeaxanthin: findings from the Third National Health and Nutrition Examination Survey. J Nutr. 2004 Sep;134(9):2387-94.

11.Hammond BR Jr, Johnson EJ, Russell RM, Krinsky NI, Yeum KJ, Edwards RB, Snodderly DM. Dietary modification of human macular pigment density. Invest Ophthalmol Vis Sci. 1997 Aug;38(9):1795-801.

12.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. 1999 Aug;70(2):247-51.

13.Johnson EJ, Hammond BR, Yeum KJ, Qin J, Wang XD, Castaneda C, Snodderly DM, Russell RM. Relation among serum and tissue concentrations of lutein and zeaxanthin and macular pigment density. Am J Clin Nutr. 2000 Jun;71(6):1555-62.

14.Koh HH, Murray IJ, Nolan D, Carden D, Feather J, Beatty S. Plasma and macular responses to lutein supplement in subjects with and without age-related maculopathy: a pilot study. Exp Eye Res. 2004 Jul;79(1):21-7.

15.Landrum JT, Bone RA, Joa H, Kilburn MD, Moore LL, Sprague KE. A one year study of the macular pigment: the effect of 140 days of a lutein supplement. Exp Eye Res. 1997 Jul;65(1):57-62.

16.Moeller SM, Jacques PF, Blumberg JB. The potential role of dietary xanthophylls in cataract and age-related macular degeneration. J Am Coll Nutr. 2000 Oct;19(5 Suppl):522S-527S.

17.Molldrem KL, Li J, Simon PW, Tanumihardjo SA. Lutein and beta-carotene from lutein-containing yellow carrots are bioavailable in humans. Am J Clin Nutr. 2004 Jul;80(1):131-6.

18.Mozaffarieh M, Sacu S, Wedrich A. 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 11;2(1):20.

19.Pratt S. Dietary prevention of age-related macular degeneration. J Am Optom Assoc. 1999 Jan;70(1):39-47.

20.Riso P, Brusamolino A, Ciappellano S, Porrini M. Comparison of lutein bioavailability from vegetables and supplement. Int J Vitam Nutr Res. 2003 May;73(3):201-5.

21.Roodenburg AJ, Leenen R, van het Hof KH, Weststrate JA, Tijburg LB. Amount of fat in the diet affects bioavailability of lutein esters but not of alpha-carotene, beta-carotene, and vitamin E in humans. Am J Clin Nutr. 2000 May;71(5):1187-93.

22.Seddon JM, Ajani UA, Sperduto RD, Hiller R, Blair N, Burton TC, Farber MD, Gragoudas ES, Haller J, Miller DT, et al. 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.

23.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. 1998 Aug;82(8):907-10.

24.Sommerburg OG, Siems WG, Hurst JS, Lewis JW, Kliger DS, van Kuijk FJ. Lutein and zeaxanthin are associated with photoreceptors in the human retina. Curr Eye Res. 1999 Dec;19(6):491-5.


EDITOR'S NOTE: This monograph can be found in The Health Professional's Guide to Dietary Supplements (Lippincott, Williams & Wilkins) by Shawn M. Talbott, PhD and Kerry Hughes, MS.

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