Eat This Once a Day to Protect Your Eyes and Improve Brain Function

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Added to salads or smoothies, its green, creamy texture is high in fiber and chock-full of vitamins, minerals, phytochemicals and healthy fats. One important carotenoid found in this nutrient-dense fruit is lutein, known for its ability to protect the eyes from harmful light at the blue end of the spectrum. It’s old news that lutein supports good vision. But now we know it does far more. It also protects the brain and improves cognition. That's why we should all aim to include plenty of lutein in our diets. And one of the best ways of achieving this is to regularly eat avocados. These are the benefits you’ll reap...

Lutein Accumulates in the Eyes & Brain

Lutein is able to cross the blood-brain barrier to concentrate in the macula at the back of the eye together with other carotenoids called zeaxanthin and meso-zeaxanthin. These make up the macular pigment which gives us clear central vision. But these carotenoids also build up in the brain. A research group from Ireland found the amount of these carotenoids in the eyes was closely correlated with concentrations in the brain. In their study of 4,453 adults aged 50 or over, they found those with lower density of macular pigment performed worse on cognitive tests. They had poorer prospective memory (remembering to carry out a future task), slower reaction times and took longer to complete certain assignments.1 Scientist Elizabeth Johnson from Tufts University in Boston has been a research leader in this area. In a study published in 2013 involving a group of nearly 300 octogenarians and centenarians, Johnson and her colleagues found that lutein concentrations were linked to better cognitive performance in a variety of ways.2 In a follow-up 2014 study, she and her research team enrolled 108 men and women aged between 75 and 80. They found those with greater amounts of macular pigment enjoyed better overall cognitive function including verbal learning and fluency, recall, processing speed and perceptual speed (how quickly figures or symbols can be located).3

The Body Easily Absorbs Lutein in Avocado

In their most recent trial, carried out last year, the Tufts researchers were interested in the cognitive effects of eating avocados. Although colorful fruits and vegetables like corn, kiwis, squash, pumpkin and spinach contain much higher amounts of lutein, the researchers chose avocados because the good fats they contain give lutein high bioavailability. The six-month randomized, controlled trial included 40 healthy people aged 50 or over. 20 added one avocado a day to their diet while the other 20 ate one potato or one cup of chickpeas. Each of these foods provided a similar amount of calories, but while a single avocado provided half a milligram of lutein, the other choices provided virtually none. The researchers carried out tests for density of macular pigment and cognitive performance at the beginning of the trial, and again at three and six months. Results showed an increase of one-fourth in macular density in the avocado group compared to only 11% in the control group. The avocado group also experienced a significant improvement in working memory and ability to solve problems compared to the controls.4 Dr. Johnson commented, "The results of this study suggest that the monounsaturated fats, fiber, lutein and other bioactives make avocados particularly effective at enriching neural lutein levels, which may provide benefits for not only eye health, but for brain health."5

Learn about Healthy Fats

Many people are concerned by the fat levels in avocados, but in this study there was no significant gain in weight among the avocado group. As I’ve stressed repeatedly for many years, the fats in nuts, avocados, coconuts and olives are good for you. They do NOT pose a danger to health or waistline. Avocados have been shown to increase HDL "good" cholesterol, lower LDL "bad" cholesterol and reduce triglycerides (blood fats), so you can eat them every day with no worries.

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