MyVisionTest News Archive
Feb 11, 2012
Lutein and zeaxanthin improve vision function in early AMD
Lutein-only and zeaxanthin-only supplementation for 12 months each increased macular pigment optical density (MPOD) and improved visual function in men with mild to moderate age-related macular degeneration (AMD).
Macular pigment is composed principally of 2 isomeric carotenoids, lutein (L), zeaxanthin (Zx), and the L metabolite meso-Zx (meso-Zx is also found in minimal amounts in seafood). In the central 3 mm of the macula, L, Zx, and MZ are present in approximately equal amounts. The macula selectively concentrates L and Zx at levels up to 1,000 times greater than found in any other body tissues. Furthermore, the macula selectively places Zx in its foveal center where the greatest protection is needed, which is last to degenerate. Zx has a chemical structure with an extra conjugated double bond (11 conjugated double bonds vs. 10 for L) and may make this a superior antioxidant. Zx is a minor component of the diet of the population of the United States (chiefly corn and yellow peppers), being no greater than one fourth as prevalent as L. By contrast, a cup of Chinese goji (Wolfberry, Fructus barbarum) berries is the highest known Zx food source, having some 200 times the amount in a cup of corn and 65 times the Zx dose found in a cup of yellow peppers. Despite the fact that L is at least 4 times as prevalent as Zx in human serum, there is a greater concentration of Zx in the central portion of the macula by 2 times. This fact has been shown in quail, monkeys, and humans. Also, relative intake of Zx to L decreases with age.
It is known that dietary L and Zx increases human MPOD. The possibility for AMD vision improvement by macular pigment enhancement with carotenoids or nutritional cofactors has been confirmed by multiple prospective interventional and observational clinical trials.
Methods & Results
This was a 1-year, n = 60 (57 men, 3 women), 4-visit, intention-to-treat, prospective, randomized controlled clinical trial of patients (74.9 years) with mild-to-moderate age-related macular degeneration (AMD) randomly assigned to 1 of 2 dietary supplement carotenoid pigment intervention groups: 8 mg Zx (n = 25) and 8 mg Zx plus 9 mg lutein (L) (n = 25) or 9 mg L ("Faux Placebo," control group, n = 10). Estimated foveal heterochromic flicker photometry, 1° macular pigment optical density (MPOD QuantifEye), low- and high-contrast visual acuity, foveal shape discrimination, 10° yellow kinetic visual fields (KVF), glare recovery, contrast sensitivity function (CSF), and 6° blue cone ChromaTest color thresholds were obtained serially at 4, 8, and 12 months.
Ninety percent of subjects completed = 2 visits with an initial Age-Related Eye Disease Study retinopathy score of 1.4/4.0 and pill intake compliance of 96% with no adverse effects. There were no intergroup differences in 3 major AMD risk factors: age, smoking, and body mass index as well as disease duration and Visual Function Questionnaire 25 composite score differences. Randomization resulted in equal MPOD variance and MPOD increasing in each of the 3 groups from 0.33 density units (du) baseline to 0.51 du at 12 m, (P = 0.03), but no between-group differences. In the Zx group, detailed high-contrast visual acuity improved by 1.5 lines, Retina Foundation of the Southwest shape discrimination sharpened from 0.97 to 0.57 (P = 0.06, 1-tail), and a larger percentage of Zx patients experienced clearing of their KVF central scotomas (P = 0.057). The "Faux Placebo" L group was superior in terms of low-contrast visual acuity, CSF, and glare recovery, whereas Zx showed a trend toward significance.
Discussion & Conclusions
In this study Zx or L significantly elevated low-normal MPOD to normal ranges in older men with AMD at 1 year, and they benefited visually from this intervention. These results may not be generalized to women, who typically have a higher percentage of adipose fat and different lipoprotein profiles.
This data suggest that Zx has unique visual cone-enhancing attributes consistent with its foveal position. Zx improved high-contrast visual acuity by 1.5 lines and sharpened 1° Foveal Shape Discrimination, a test of foveal cone alignment. In some cases, the macula kinetic visual field data and correlative 3-dimensional MPOD plots demonstrated complete resolution of central scotomas. The autofluorescence lipofuscin data suggested amelioration. In the rod-dominant parafovea L, ostensibly owing to its more parafoveal retinal distribution, proved superior, with statistically significant improvement in contrast sensitivity, glare recovery, and enhanced blue-yellow increment db thresholds from parafoveal blue cones. These visual effects were not mutually exclusive, as there were weak trends toward significance with Zx for rod-dominant visual parameters, while the L group also manifested overlapping properties with respect to cone function.
This study also investigated whether there was added benefit of Zx to traditional L supplementation. In this case, higher dose 1:1 ratio of Zx plus L barely increased MPOD and inconsistently enhanced visual function, suggesting carotenoid duodenal, hepatic-lipoprotein, or retinal competition when introduced at equal supplement doses. This is not surprising, as dietary L predominates 5:1 and foveal Zx predominates 2:1 over L, so equal doses of each carotenoid are unusual from a dietary or tissue standpoint.
In the current study not everyone who was supplemented experienced elevated MPOD, as reported by others.
Macular pigment is associated with all 3 primary AMD risk factors—age, smoking, and obesity. Evidence from epidemiologic studies consistently shows high dietary intake of fruits and vegetables rich in L and Zx reduces the risk of AMD.
This study is consistent with other studies showing that Zx raises MPOD. Raising macular pigment via Zx supplementation results in salutary visual benefits to AMD patients with mild disease, through enhancement of visual acuity, shape discrimination, scotoma resolution, as well as weaker negative effects on CSF, glare recovery, and blue-yellow color thresholds.
Patients with AMD might want to enhance their declining vision with carotenoids apart from the question of whether carotenoid supplementation can decrease the risk of progression to end-stage disease. MPOD enhancement via dietary manipulation is possible.
MPOD measurement is rarely used in clinical practice. This results in failure to capture the subtleties of disease progression that we can correlate to patient complaints. The aging of the U.S. population and attendant increase in AMD has implications for night driving and public safety.
In summary, supplementation with high dose Zx (8 mg), L (9 mg), or both resulted in increased MPOD and improvements in macular function. All three supplements produced nearly equal improvement in MPOD by heterochromic flicker photometry (no significant between-group differences) and improvements in vision function.
Read more...
Optometry. 2011 Nov;82(11):667-680
Tags: AMD, lutein, antioxidants, diet
Lutein-only and zeaxanthin-only supplementation for 12 months each increased macular pigment optical density (MPOD) and improved visual function in men with mild to moderate age-related macular degeneration (AMD). Macular pigment is composed principally of 2 isomeric carotenoids, lutein (L), zeaxanthin (Zx), and the L metabolite meso-Zx (meso-Zx is also found in minimal amounts in seafood). In the central 3 mm of the macula, L, Zx, and MZ are present in approximately equal amounts. The macula selectively concentrates L and Zx at levels up to 1,000 times greater than found in any other body tissues. Furthermore, the macula selectively places Zx in its foveal center where the greatest protection is needed, which is last to degenerate. Zx has a chemical structure with an extra conjugated double bond (11 conjugated double bonds vs. 10 for L) and may make this a superior antioxidant. Zx is a minor component of the diet of the population of the United States (chiefly corn and yellow peppers), being no greater than one fourth as prevalent as L. By contrast, a cup of Chinese goji (Wolfberry, Fructus barbarum) berries is the highest known Zx food source, having some 200 times the amount in a cup of corn and 65 times the Zx dose found in a cup of yellow peppers. Despite the fact that L is at least 4 times as prevalent as Zx in human serum, there is a greater concentration of Zx in the central portion of the macula by 2 times. This fact has been shown in quail, monkeys, and humans. Also, relative intake of Zx to L decreases with age.
Methods & Results
This was a 1-year, n = 60 (57 men, 3 women), 4-visit, intention-to-treat, prospective, randomized controlled clinical trial of patients (74.9 years) with mild-to-moderate age-related macular degeneration (AMD) randomly assigned to 1 of 2 dietary supplement carotenoid pigment intervention groups: 8 mg Zx (n = 25) and 8 mg Zx plus 9 mg lutein (L) (n = 25) or 9 mg L ("Faux Placebo," control group, n = 10). Estimated foveal heterochromic flicker photometry, 1° macular pigment optical density (MPOD QuantifEye), low- and high-contrast visual acuity, foveal shape discrimination, 10° yellow kinetic visual fields (KVF), glare recovery, contrast sensitivity function (CSF), and 6° blue cone ChromaTest color thresholds were obtained serially at 4, 8, and 12 months.
Ninety percent of subjects completed = 2 visits with an initial Age-Related Eye Disease Study retinopathy score of 1.4/4.0 and pill intake compliance of 96% with no adverse effects. There were no intergroup differences in 3 major AMD risk factors: age, smoking, and body mass index as well as disease duration and Visual Function Questionnaire 25 composite score differences. Randomization resulted in equal MPOD variance and MPOD increasing in each of the 3 groups from 0.33 density units (du) baseline to 0.51 du at 12 m, (P = 0.03), but no between-group differences. In the Zx group, detailed high-contrast visual acuity improved by 1.5 lines, Retina Foundation of the Southwest shape discrimination sharpened from 0.97 to 0.57 (P = 0.06, 1-tail), and a larger percentage of Zx patients experienced clearing of their KVF central scotomas (P = 0.057). The "Faux Placebo" L group was superior in terms of low-contrast visual acuity, CSF, and glare recovery, whereas Zx showed a trend toward significance.
Discussion & Conclusions
In this study Zx or L significantly elevated low-normal MPOD to normal ranges in older men with AMD at 1 year, and they benefited visually from this intervention. These results may not be generalized to women, who typically have a higher percentage of adipose fat and different lipoprotein profiles.This data suggest that Zx has unique visual cone-enhancing attributes consistent with its foveal position. Zx improved high-contrast visual acuity by 1.5 lines and sharpened 1° Foveal Shape Discrimination, a test of foveal cone alignment. In some cases, the macula kinetic visual field data and correlative 3-dimensional MPOD plots demonstrated complete resolution of central scotomas. The autofluorescence lipofuscin data suggested amelioration. In the rod-dominant parafovea L, ostensibly owing to its more parafoveal retinal distribution, proved superior, with statistically significant improvement in contrast sensitivity, glare recovery, and enhanced blue-yellow increment db thresholds from parafoveal blue cones. These visual effects were not mutually exclusive, as there were weak trends toward significance with Zx for rod-dominant visual parameters, while the L group also manifested overlapping properties with respect to cone function.
This study also investigated whether there was added benefit of Zx to traditional L supplementation. In this case, higher dose 1:1 ratio of Zx plus L barely increased MPOD and inconsistently enhanced visual function, suggesting carotenoid duodenal, hepatic-lipoprotein, or retinal competition when introduced at equal supplement doses. This is not surprising, as dietary L predominates 5:1 and foveal Zx predominates 2:1 over L, so equal doses of each carotenoid are unusual from a dietary or tissue standpoint.
In the current study not everyone who was supplemented experienced elevated MPOD, as reported by others.
Macular pigment is associated with all 3 primary AMD risk factors—age, smoking, and obesity. Evidence from epidemiologic studies consistently shows high dietary intake of fruits and vegetables rich in L and Zx reduces the risk of AMD.
This study is consistent with other studies showing that Zx raises MPOD. Raising macular pigment via Zx supplementation results in salutary visual benefits to AMD patients with mild disease, through enhancement of visual acuity, shape discrimination, scotoma resolution, as well as weaker negative effects on CSF, glare recovery, and blue-yellow color thresholds.
Patients with AMD might want to enhance their declining vision with carotenoids apart from the question of whether carotenoid supplementation can decrease the risk of progression to end-stage disease. MPOD enhancement via dietary manipulation is possible.
MPOD measurement is rarely used in clinical practice. This results in failure to capture the subtleties of disease progression that we can correlate to patient complaints. The aging of the U.S. population and attendant increase in AMD has implications for night driving and public safety.
In summary, supplementation with high dose Zx (8 mg), L (9 mg), or both resulted in increased MPOD and improvements in macular function. All three supplements produced nearly equal improvement in MPOD by heterochromic flicker photometry (no significant between-group differences) and improvements in vision function.
Read more...
Optometry. 2011 Nov;82(11):667-680
