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).3The 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."5Learn 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.- https://www.ncbi.nlm.nih.gov/pubmed/23769396
- https://www.ncbi.nlm.nih.gov/pubmed/23840953
- https://www.ncbi.nlm.nih.gov/pubmed/24435852
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5622679
- https://www.news-medical.net/news/20170824/Research-Avocado-consumption-may-lead-to-improved-cognitive-function-in-healthy-older-adults.aspx
