Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.
For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.
3 Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2 Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1 Star For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.
15 mg three times per week
People with high intakes of the carotenoid lutein have been reported to be at a low risk for cataracts.
People with low blood levels of antioxidants and those who eat few antioxidant-rich fruits and vegetables have been reported to be at high risk for cataracts.1 , 2
People who eat a lot of spinach and kale, which are high in lutein and zeaxanthin, carotenoids similar to beta-carotene, have been reported to be at low risk for cataracts.3 , 4 Lutein, zeaxanthin, and beta-carotene offer the promise of protection because they are antioxidants. It is quite possible, however, that lutein is more important than beta-carotene, because lutein is found in the lens of the eye, while beta-carotene is not.5 In one preliminary study, lutein and zeaxanthin were the only carotenoids associated with protection from cataracts.6 People with the highest intake of lutein and zeaxanthin were half as likely to develop cataracts as those with the lowest intake. In another study, supplementation with 15 mg of lutein three times a week for one year significantly improved visual function in a small group of people with age-related cataracts.7
Macular Degeneration (Zeaxanthin)
6 to 10 mg daily
Lutein and zeaxanthin are antioxidants that protect the retina from damage caused by sunlight. Lutein has been shown to help people with both early and advanced stages of the disease.
Lutein and zeaxanthin are antioxidants in the carotenoid family. These carotenoids, found in high concentrations in spinach, collard greens, and kale, have an affinity for the part of the retina where macular degeneration occurs. Once there, they protect the retina from damage caused by sunlight.8
Harvard researchers reported that people eating the most lutein and zeaxanthin—an average of 5.8 mg per day—had a 57% decreased risk of macular degeneration, compared with people eating the least.9 While spinach and kale eaters have a lower risk of macular degeneration, blood levels of lutein did not correlate with risk of macular degeneration in one trial.10 , 11 In a double-blind study of people with macular degeneration, supplementation with lutein (10 mg per day) for one year significantly improved vision, compared with a placebo.12 Lutein was beneficial for people with both early and advanced stages of the disease. Lutein and zeaxanthin can be taken as supplements; 6 mg per day of lutein may be a useful amount.
People showing protection from macular degeneration have been reported to have eaten about 6 mg of lutein per day from food. Lutein, in supplemental form, should be taken with fat-containing food to improve absorption.13
Spinach, kale, collard greens, romaine lettuce, leeks, peas, and egg yolks are good sources of lutein.14
While a deficiency has not been identified, people who eat more lutein-containing foods appear to be at lower risk of macular degeneration. One study found that adults with the highest dietary intake of lutein had a 57% decreased risk of macular degeneration compared with those people with the lowest intake, and of the carotenoids, lutein and zeaxanthin are most strongly associated with this protection.15 In a preliminary study, a similar link was suggested between low dietary lutein and increased risk of cataracts.16
Lutein functions together with zeaxanthin, another antioxidant found in the same foods and supplements as lutein.
1. Jacques PF, Chylack LT Jr. Epidemiologic evidence of a role for the antioxidant vitamins and carotenoids in cataract prevention. Am J Clin Nutr 1991;53:352S–5S.
2. Knekt P, Heliovaara M, Rissanen A, et al. Serum antioxidant vitamins and risk of cataract. BMJ 1992;305:1392–4.
3. Hankinson SE, Stampfer MJ, Seddon JM, et al. Nutrient intake and cataract extraction in women: a prospective study. BMJ 1992;305:335–9.
4. Chasan-Taber L, Willett WC, Seddon JM, et al. A prospective study of carotenoid and vitamin A intakes and risk of cataract extraction in US women. Am J Clin Nutr 1999;70:509–16.
5. Yeum K-J, Taylor A, Tang G, Russell RM. Measurement of carotenoids, retinoids, and tocopherols in human lenses. Ophthalmol Vis Sci 1995;36:2756–61.
6. 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 1999;149:801–9.
7. Olmedilla B, Granado F, Blanco I, Vaquero M. Lutein, but not alpha-tocopherol, supplementation improves visual function in patients with age-related cataracts: a 2-y double-blind, placebo-controlled pilot study. Nutrition 2003;19:21–4.
8. Bone RA. Landrum JT. Distribution of macular pigment components, zeaxanthin and lutein, in human retina. Methods Enzymol 1992:213:360–6.
9. Seddon JM, Ajani UA, Sperduto RD, et al. Dietary carotenoids, vitamins A, C, and E, and advanced age-related macular degeneration. JAMA 1994:272:1413–20.
10. Blumenkranz MS, Russell SR, Robey MG, et al. Risk factors in age-related maculopathy complicated by choroidal neovascularization. Ophthalmology 1986:93:552–8.
11. Mares-Perlman JA, Brady WE, Kleain R, et al. Serum antioxidants and age-related macular degeneration in a population-based case-control study. Arch Ophthalmol 1995;113:1518–23.
12. Richer S, Stiles W, Statkute L, 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 2004;75:216–30.
13. Roodenburg AJ, Leenen R, van het Hof KH, et al. 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;71:1187–93.
14. Goodrow EF, Wilson TA, Houde SC, et al. Consumption of one egg per day increases serum lutein and zeaxanthin concentrations in older adults without altering serum lipid and lipoprotein cholesterol concentrations. J Nutr 2006;136:2519–24.
15. Seddon JM, Ajani UA, Sperduto RD, et al. Dietary carotenoids, vitamins A, C, and E, and advanced age-related macular degeneration. JAMA 1994;272:1413–20.
16. Hankinson SE, Stampfer MJ, Seddon JM, et al. Nutrient intake and cataract extraction in women: a prospective study. Br Med J 1992;305(6849):335–9.
Last Review: 05-01-2013
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The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2014.
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