Focus on healthy eating for the eyes, the brain


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The human diet includes about 50 of the 700+ carotenoids found in nature, and only a few of these carotenoids are able to cross the blood-brain barrier and accumulate in nervous tissue.

Lutein is the dietary carotenoid that is found in the highest concentration in the brain. And lutein, along with zeaxanthin and meso-zeaxanthin, also accumulates in the retina.

These macular xanthophylls are known to be powerful antioxidants that are found in high concentrations in dark, leafy vegetables such as spinach and cabbage, as well as in other brightly colored foods such as corn, eggs and avocados. Their presence in the brain is probably part of the body’s strategy to protect oxygen-critical nerve tissue from oxidative damage, which promotes inflammation and over time contributes to neurodegenerative disease.

James M. Stringham, Ph.D.

James M. Stringham

There are now a large number of studies demonstrating the value of macular xanthophylls for visual and cognitive function (Stringham, Johnson et al.). Most Americans do not eat enough of foods containing lutein and zeaxanthin, and 15% to 20% of people lack the enzymes needed to convert meso-zeaxanthin to lutein.

In 2019, my colleagues and I demonstrated for the first time that a daily diet of supplements containing these three nutrients can significantly reduce the inflammatory marker interleukin-1 in the blood and increase the neurotrophic factor produced by the brain (BDNF), a molecule associated with neuroplasticity (Stringham, Holmes, etc.). Only after 6 months of admission, we saw improved cognitive performance parameters, including processing speed, memory, and attention, among healthy young students in the study.

Another study found that pre-death knowledge among centenarians in Georgia was directly related to the amount of lutein in their brains after death (Mohn et al.). This finding hinted to those of us in the world of carotenoid / neural health research that macular xanthophylls may have a protective effect against brain damage.

Oxidative stress is behind many of the negative outcomes of traumatic brain injury (TBI), and it has been suggested that different levels of macular xanthophyll may have something to do with the wide variety in the severity of TBI and recovery time. Of course, this is a difficult hypothesis for controlled testing in humans. Instead, a validated murine concussion model (Gunal et al.) Was used to test this idea.

Just as observed in our students taking a daily macular xanthophyll supplement, treatment of “shaken” mice with the three macular carotenoids reduced proinflammatory cytokines and increased BDNF compared with placebo. More importantly, mice had a dramatic reduction in the harmful effects of TBI, including infarct size, cerebral edema, light and sound sensitivity, and vestibular dysfunction.

This is exciting because it is applicable. Many optometrists already recommend that patients supplement or increase their dietary intake of lutein, zeaxanthin, and meso-zeaxanthin for the macular benefits of these nutrients. This study suggests that the addition of macular xanthophyll may also aid in improved knowledge and provide significant protection against brain damage and oxidative damage.

Optometrists should know that not all supplements are created the same. I recommend looking for additives made by pharmaceutical grade treatment, with demonstrated bioavailability and third-party testing that proves that the additive contains what the label says it does.

As optometrists move to more comprehensive medical care, focusing on healthy eating can be a great way to support patients’ eyes – and their brains.

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James M. Stringham, Ph.D. is a neurologist with a lifelong interest in the effects of nutrition on the eyes and brain. He has published more than 50 peer-reviewed articles and technical reports and has given more than 300 lectures on the health benefits of lutein, zeaxanthin and meso-zeaxanthin. Stringham completed his postdoctoral fellowship at Harvard and the University of Georgia, served as a vision scientist in the Air Force Research Laboratory, and taught at Duke University. He is currently the Chief Research Fellow at MacuHealth. He will teach a course on “New Evidence for Nutrition-Based Strategies to Minimize Concussion / Trauma” at the NORA Conference in 2022. For more information and registration, visit https://noravisionrehab.org/about-nora/annual- conferences / 2022-annual-conference.

Disclaimer: The opinions and opinions expressed in this blog are those of the authors and do not necessarily reflect the official policy or position of the Association for Neuro-Optometric Rehabilitation, unless otherwise stated. This blog is for informational purposes only and is not a substitute for a doctor’s professional medical advice. NORA does not recommend or endorse any specific tests, doctors, products or procedures. For more information about our website and online content, click here.

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