Lutein is a carotenoid found in yellow- and orange-colored fruits and vegetables like mangoes, corn, sweet potatoes, carrots, squash, tomatoes and dark, leafy greens such as kale, collards and bok choy. The carotenoid is famous for its ability to protect against common eye disorders such as cataracts and macular degeneration. In addition, lutein and zeaxanthin absorb harmful blue light from the sun, which can damage the retina. A further study of the compound revealed that it plays a role in preventing blood clots in the carotid artery in the neck, one of the indicators for atherosclerosis. In contrast, a deficiency in lutein showed a worsening of arterial clogging. Still, experts haven't fully explored its effects in the human body, including the best route for nutrient absorption.
In a study, participants added one medium avocado to their daily diet. The researchers then measure their lutein levels and any improvement in cognition using various tests for memory, processing speed, and attention level – where their results were compared with that of a control group, which had either one medium potato or a cup of chickpeas, in place of the avocado. Researchers used chickpeas and potatoes since both have a calorie level similar to that of avocados, but negligible amounts of lutein and monounsaturated fats. Based on the results, those who ate avocados had a 25 percent increase in lutein levels in their eyes.
According to lead investigator Dr. Elizabeth Johnson, the results of the study point out to the avocado's ability to support lutein levels in the brain, which translates not only to improvements in eye health but for brain health as well. In particular, the use of fresh avocados was essential for increased lutein absorption – the results that the current study posted were twice higher than that of supplements, based on her previous research.
"A balanced diet that includes fresh avocados may be an effective strategy for cognitive health," she added.
The study, which was supported by the Hass Avocado Board, was based on the consumption of one whole avocado, which contains 369 micrograms of lutein. According to researchers, further studies are needed to replicate their results on smaller portions of avocados. (Related: Avocado nutrition facts - six things about this amazingly healthy superfood.)
"While the conclusions drawn are from a single study that cannot be generalized to all populations, the study's outcome helps to reinforce and advance the body of published research on avocado benefits and their role in everyday healthy living," concluded Dr. Nikki Ford of the Hass Avocado Board. "Avocados are a nutrient-dense, cholesterol-free fruit with naturally good fats, and are a delicious and easy way to add more fruits and vegetables to everyday healthy eating plans."
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