Lutein & Zeaxanthin (2015, 2016) Role in Vision & Disease

Learn more about zeaxanthin and Ma href="http://www.naturaleyecare.com/nutrients/antioxidants/lutein.asp">lutein.

Lutein and zeaxanthin, two important carotenoids in the eye do much more than simply defend against macular degeneration and other eye diseases.

Retinal and macular support. These carotenoid antioxidants have been found to be helpful in protecting the health of the macula and in fighting macular degeneration and other conditions involving macular health.

Retinal pigment. One of their benefits to macular degeneration is because they are retinal pigments that filter damaging UV radiation from the sun. While leafy green vegetables are important contributors of these carotenoids, the lutein and zeaxanthin supplied by red and orange foods provides better support for formation of retinal pigment.

In a cross-section study researchers assessed dietary consumption of fruits, vegetables, and eggs based on intake recalls and a carotenoid database. The carotenoids came mostly from vegetables (~80%+), eggs, and fruits (3% (lutein) & 15% (zeaxanthin). Most of the carotenoids came from the green foods, but when macular pigment density was measured it was found that the red and orange foods had a greater effect.

Editor's note: there is now a wide understanding among researchers that greater macular pigment density is associated with a lower risk of developing macular degeneration and other macular conditions.

Researchers: R. Estevez-Santiago, et al.
Published: Lutein and zeaxanthin supplied by red/orange foods and fruits are more closely associated with macular pigment optical density than those from green vegetables in Spanish subjects, Nutrition Research, November, 2016.

Glare recovery. Optometrists who are diagnosing vision problems use a standard test called a glare recovery test to determine whether the problem originates from the macula or the optic nerve. The doctor shines a bright light at the patient's eyes, or has the patient look at the eye chart through a ring of bright lights. If the macula is the source of problems the patient has difficulty in seeing through the ring of lights or takes a long time to see the eye chart letters after the bright light is shined at his eyes. If the optic nerve is involved the bright lights do not pose a problem.

When the macular pigment has greater density, glare recovery is much better and the carotenoids lutein, zeaxanthin and meso-zeaxanthin improve the thickness and density of the pigmented layer of the retina.

Researchers: J. M. Stringham, et al.
Published: Macular carotenoid supplementation improves disability glare performance and dynamics of photostress recovery, Eye and Vision, November, 2016.

Biomarker role. Biomarkers are the measurable nutrients or vitamins or other biochemicals found in the blood that help medical professionals in diagnosis.

Researchers have determined that lutein and zeaxanthin are excellent biomarker when evaluating the quality of women's diets. Over 150 post-menopause women followed a specific diet for two weeks before blood samples were tested. A number of biomarkers were measured before and after the test. They included carotenoids, B-12, tocopherols, folate, and some fatty acids. All of these except the fatty acids and tocopherols were identified as very good biomarkers that will be useful in diagnostics.

Researchers: J. W. Lampe, et al.
Dietary biomarker evaluation in a controlled feeding study in women from the Women's Health Initiative cohort, American Journal of Clinical Nutrition, December, 2016.

Cancer. Scientists have long thought that carotenoids might be helpful in reducing the risk of non-Hodgkin lymphoma, but the data has been inconsistent. Researchers performed a meta-analysis (a study of studies - which yields a sum larger sample size and more accurate results) of ten studies which met their requirements for inclusion.

They found that higher consumption of the carotenoids lutein and zeaxanthin as well as alpha- and beta-carotene were tied to a markedly lower risk of "diffuse large B-cell lymphoma, but not follicular lymphoma or small lymphocytic lymphoma/chronic lymphocytic leukemia".

Researchers: F. Chen, et al.
Carotenoid intake and risk of non-Hodgkin lymphoma: a systematic review and dose-response meta-analysis of observational studies, Annals of Hemotology, December, 2016.

Stem cell support. Many new treatments for health problems are being addressed through stem cell transplantation. The problem is that the body's immune system may reject the transplanted cells. Researchers specifically investigating stem cell transplantation treatment for liver failure determined that such stem cells are vulnerable to inflammation and oxidative stress causing high rates of cell death.

They found in in-vitro testing that pre-treatment with zeaxanthin was helpful in supporting the defense mechanism of transplanted stem cells and made them more capable of repairing liver tissue.

Researchers: Y. Liu, et al.
Published: Precise Regulation of miR-210 is Critical for the Cellular Homeostasis Maintenance and Transplantation Efficacy Enhancement of Mesenchymal Stem Cell in Acute Liver Failure Therapy, Cell Transplantation, December, 2016.

Fracture. Yet another interesting new study connects carotenoid levels in the body with risk of fracture. A meta-analysis of seven studies which included a total of over 140,000 subjects and another over-4000 specific cases found that there was a close relationship between levels of carotenoids circulating in the blood plasma with the risk of fracturing a bone.

Patients who consumed high levels of carotenoids such as lutein and zeaxanthin, as well as beta-carotene had a 28% lower chance of having a hip fracture. However there was significant variation between the different studies, so although the average demonstrates a connection, further research is needed to validate these results.

Researchers: J. Xu, C. Song, et.al.
Published: Carotenoids and risk of fracture: a meta-analysis of observational studies, Oncotarget, November, 2016.

Atherosclerosis

Other new research connects higher levels of lutein with lower incidence of artherosclerosis (coronary heart disease).

Other research For a more in-depth review of the broad range of benefits from these essential carotenoids see this article published in the International Journal of Retina and Vitreous in August, 2016.