Study: Lutein, Zeaxanthin (1990s, 2000, 03, 05, 06, 08) in Diet: Macular Degeneration
Learn more about the macula.
Scientists have established that macular pigments are located in the retina. Lutein (in the periphery of the macula) and zeaxanthin (in the central area of the macula) make up these carotenoid macular pigments discussed in the following studies.
Researchers noted that lutein and zeaxanthin, which come from dark leafy greens are tied to reduced macular degeneration risk. Patients with the highest levels of these carotenoids in their diet had a 43% lower risk of developing AMD. These pigments filter blue light from the retina and protect it from oxidative damage.
Researchers: Seddon, et al.
Published: Journal of the American Medical Association, November, 1994
Researchers analyzed lab data for different antioxidant carotenoids which help protect the eye from oxidative damage due to blue light. They found that lutein and zeaxanthin, which form the macular pigment have the strongest protecting effects.
Researchers: D.M. Snodderly, et al.
Published: American Journal of Clinical Nutrition, December, 1995
Researchers investigated the amount and condition of macular pigment in 13 patients who were on a diet including daily spinach and corn for up to almost 4 months. The pigments in the macula are responsible for protection against damaging UV radiation from the sun which is a contributing factor in macular degeneration.
The daily servings of corn and spinach add 11.2mg lutein and .6mg zeaxanthin to the daily diet - which compared to a 'normal' diet, was 3x (lutein) and 4x (zeaxanthin) the nutrient amounts the patients would have received otherwise. They found in 80% of the patients who followed the diet an average increase in pigment density of 19% - with the minimum increase being 13%.
Researchers: Hammond, et al
Published: Dietary modification of human macular pigment density, Investigations in Ophthalogy and Visual Science, August, 1997.
Zeaxanthin comprises up to 75% of the total carotenoids in the center of the macula. Lutein comprises 67% or more of the peripheral area of the macula. Concentrations of these carotenoids in other tissues of the body are much lower. It has been determined that these pigments increase in both tissue and blood by way of diet and supplementation. Evidence points to a correlation between macular pigment density and a reduction in the risk for age-related macular degeneration.
Researchers: John T. Landrum, et al
Published: Analysis of Zeaxanthin Distribution within Individual Human Retinas, Methods In Enzymology, 1999.
This understanding, that these important carotenoid antioxidants are important for macular health, further developed in later research in which seven subjects again consumed spinach and corn in their daily diets for another nearly 4 months. In this study at the beginning of the study period and at 4, 8 and 15 weeks, and 2 months after the study's end, blood samples, cells from the inside of cheeks and fat tissue were assessed, as well as measuring macular pigment density.
Zeaxanthin was greater after 4 weeks than after the beginning, but did not peak further than that level. Lutein peaked at 8 weeks. There were differences in the relationship of these carotenoid levels in the different types of tissue - with negative correlations for women and positive correlations for men - indicating that sex differenes in lutein metabolism may be important in considering tissue interactions and pigment density.
Researchers: E. J. Johnson, et al
Published: Relation among serum and tissue concentrations of lutein and zeaxanthin and macular pigment density, American Journal of Clinical Nutrition, June, 2000.
In this study researchers evaluated the connection between blood plasma levels of lutein and zeaxanthin and AMD in 380 UK men and women aged 66 to 75 years old. They used the Wisconsin Age-Related Maculopathy Grading System to compare early and late macular degeneration and blood samples.
They found that the risk of both early or late starting age-related macular degeneration was higher in patients with lower blood plasma concentrations of zeaxanthin. Compared with those in the highest 1/3, people whose plasma concentration was in the lowest 1/3 had 2 times higher odds for risk of age-related macular degeneration.
Researchers: Catharine R. Gale, et al., Medical Research Council Environmental Epidemiology Unit, University of Southampton, Southampton General Hospital, Southampton, United Kingdom
Published: Investigative Ophthalmology and Visual Science. 2003
The paper summaries understandings about lutein and zeaxanthin to date.
Both lutein and zeaxanthin are carotenoids given yellow color by the pigment lutea, meaning yellow. They are found in the periphery and center of the macula respectively. Other major carotenoids such as lycopene or beta-carotene are not found in macular tissue. Researchers understand that these macular pigments probably protect the retina against damage from light and that studies demonstrate evidence that increasing intake of these carotenoids lowers the risk of developing macular degeneration by protecting the eye against oxidative damage. They acts as filters to damaging blue light and they block certain oxidative actions.
Published: Developments in Ophthalmology, 2005
A longitudinal study of women aged 50-79 in Iowa, Wisconsin and Oregon evaluated the relationship between lutein and zeaxanthin in their diet and macular degeneration incidence.
Four to seven years later the same women were included in the Carotenoids in Age-Related Eye Disease Study and the incidence of AMD was determined in almost 1800 women by means of retinal photographs.
Although the incidence of AMD was not greatly different for the groups with high and low levels of carotenoids in their diet, the researchers found that when they evaluated only those younger women (<75) who also had a stable consumption of the two carotenoids, and who also had no other history of the kind of diseases related to diet, it was found that the AMD risk was markedly reduced.
Researchers: Suzen M. Moeller, PhD, et al, CAREDS Research Study Group
Published: Archives of Opthalmology, 2006
A longitudinal study substantiated earlier conclusions.
Over 10 years researchers evaluated the diets and antioxidant supplementation and the long-term risk of age-related macular degeneration in over 2400 patients.
Subjects with greater levels of lutein and zeaxanthin intake had a reduced risk of the advanced form of wet macular degeneration, and those patients with intake levels above the median level had a lower risk of soft drusen, the fatty deposits that are characteristic of AMD.
The researchers reported that high consumption of these nutrients through diet and/or supplementation significantly reduced the risk of developing macular degeneration. It also confirmed findings about other nutrients from the first AREDS study.
Researchers: J.S.L. Tan, J.J. Wang, V. Flood, E. Rochtchina, W. Smith, P. Mitchell, Centre for Vision Research, University of Sidney, Australia
Published: Dietary Antioxidants and the Long-term Incidence of Age-Related Macular Degeneration: The Blue Mountains Eye Study, Ophthalmology, February 2008