[The authors respond:]
We agree that there is no strong research that directly examines the protective role of lutein in ocular disease. Although we recognize the limitations of epidemologic evidence, we realize that such evidence may provide some insight into the potential role of lutein in ocular disease. In addition to the article citing epidemiologic evidence that shows a potential protective effect of lutein, evidence from the NHANES (National Health and Nutrition Examination Survey) study that found no relationship was also cited. Although only randomized clinical trials would show causality, in our article we acknowledge the limitations of conducting such tightly controlled research, such as the difficulty in measuring oxidative stress in the retina. Thus, whether lutein may prevent oxidative stress in the retina remains unclear. Accordingly, we feel that our article weighs the merits and disadvantages of lutein fairly and is not strongly supportive of its role as a nutraceutical. As such, we are completely in agreement with Ari Giligson that randomized clinical trials are required to establish a more definitive position for use of the lutein as a prophylactic to ocular disease, a position that is entirely in keeping with the spirit of our article.
Footnotes
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Competing interests: None declared for Sylvia Santosa. Peter Jones is part owner of Nutritional Fundamentals for Health, a company that sells lutein as one of its products.