A recent study conducted by researchers at Tufts University’s Friedman School of Nutrition Science and Policy has revealed that incorporating pistachios into the diet can significantly enhance eye health. The improvements are attributed to lutein, a powerful plant pigment found in pistachios, which plays a critical role in protecting the eyes from blue light and age-related degeneration.
The randomized controlled trial demonstrated that eating 2 ounces (57 grams) of pistachios daily for 12 weeks, in addition to a regular diet, led to a substantial increase in macular pigment optical density (MPOD) among healthy middle-aged and older adults. MPOD, a key indicator of retinal health, is known to lower the risk of age-related macular degeneration (AMD), one of the leading causes of blindness in older individuals.
Significance of the Findings
The study’s results are noteworthy, especially as Americans have reported fearing vision loss more than other major health issues, according to a national poll conducted by the American Foundation for the Blind. The increased MPOD observed among participants after only six weeks of pistachio consumption highlights the potential for pistachios to serve as a natural dietary tool to combat AMD and protect long-term eye health.
Dr. Tammy Scott, a clinical neuropsychologist and the lead author of the study, emphasized the broader implications of these findings. “Pistachios are not just a healthy snack but also offer crucial benefits for eye health, which becomes increasingly important with age,” she said.
Role of Lutein and Pistachios in Eye Protection
Pistachios are uniquely positioned as the only nut containing measurable levels of lutein, an antioxidant crucial for eye health. Lutein acts by filtering harmful blue light and reducing oxidative damage in the eyes. The study found that consuming pistachios not only doubled participants’ intake of lutein, which tends to be insufficient in typical American diets, but also raised plasma lutein levels significantly within six weeks.
Participants in the study, who had low baseline levels of lutein, experienced rapid improvements in blood lutein concentrations after incorporating just 2 ounces of pistachios daily. Dr. Scott noted that pistachios, being rich in healthy fats, may improve lutein absorption in the body, further enhancing the protective effects on eye health.
The pistachios provided about 1.6 mg of lutein per day, which was sufficient to double the average daily intake of lutein in U.S. adults. Lutein belongs to a class of plant pigments known as xanthophylls, which accumulate in the eyes and the brain to offer protective benefits.
Additional Benefits of Lutein for Cognitive Health
Beyond its impact on vision, the lutein found in pistachios may contribute to brain health as well. Dr. Elizabeth Johnson, a co-investigator in the study, explained that lutein crosses the blood-brain barrier, where it may reduce oxidative stress and inflammation. Higher lutein levels in the brain have been associated with improved cognitive function, including better memory and faster processing speed.
The selective accumulation of lutein in the brain suggests that it may play a role in preventing cognitive decline, further underlining the value of pistachios in supporting healthy aging. These findings point to pistachios as an essential addition to diets aimed at promoting both visual and cognitive health.
Reference:
1. Tammy M. Scott. Pistachios are a bioavailable source of the xanthophyll lutein. Along with zeaxanthin. “Pistachio Consumption Increases Macular Pigment Optical Density in Healthy Adults: A Randomized Controlled Trial.” The Journal of Nutrition, October 18, 2024. https://www.sciencedirect.com/science/article/pii/S002231662401099X.
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