A new study from researchers at the Friedman School of Nutrition Science and Policy at Tufts University has found that consuming pistachios daily may significantly improve eye health by increasing macular pigment optical density (MPOD), due to the plant pigment lutein, a key factor in protecting the eyes from blue (visible) light and age-related damage.
The randomized controlled trial showed that compared to eating a usual diet alone, eating 2 ounces (57 grams) of pistachios per day for 12 weeks as part of a usual diet resulted in a significant increase in MPOD in otherwise healthy middle-aged to older adults. MPOD is an important indicator of eye health, as it protects the retina and is linked to a reduced risk of age-related macular degeneration (AMD), a leading cause of blindness in older adults.
Findings from this research are timely, as according to a national poll by the American Foundation for the Blind, Americans fear vision loss more than they fear other serious health problems.
Key findings
- Increased MPOD: Participants who consumed pistachios daily saw a significant rise in MPOD after just 6 weeks, with the effect sustained throughout the 12-week study.
- Natural Lutein Source: Pistachios are the only nut that provides a measurable source of lutein, a powerful antioxidant that helps protect the eyes.
- AMD Prevention Potential: The study suggests that regular pistachio consumption could offer a natural dietary approach to reducing the risk of AMD.
Our findings indicate that pistachios are not only a nutritious snack, but they may also provide significant benefits for eye health. This is especially important as people age and face higher risks of vision impairment."
Dr. Tammy Scott, a research and clinical neuropsychologist and lead author of the study
Unique role of lutein from pistachios and eye health
Lutein, found in pistachios, plays a critical role in maintaining eye health by filtering blue light and acting as an antioxidant in the eye. The study found that pistachio consumption nearly doubled participants' daily intake of lutein, which is typically very low in most American diets, and significantly raised plasma levels of lutein.
Dr. Scott explains that in the study, participants were selected to have low habitual baseline lutein intakes in their diet and just 2 ounces per day rapidly increased lutein levels in the blood in only 6 weeks. "By simply incorporating a handful of pistachios into your diet, you can improve your intake of lutein, which is crucial for protecting your eyes," notes Dr. Scott. She adds that pistachios provide a source of healthy fat, potentially making the lutein from pistachios better taken up into the body.
In the study, about 1.6 mg of lutein was provided from pistachios, which would be enough to double the average daily consumption of lutein, which is in a class of plant pigments known as xanthophylls, in U.S. adults.
Broader health benefits of lutein
Beyond supporting eye health, the lutein found in pistachios may also benefit brain function. "Lutein crosses the blood-brain barrier, where it may help reduce oxidative stress and inflammation," notes Dr. Elizabeth Johnson, a co-investigator on the study.
As with the eye, lutein selectively accumulates in the brain and may play a role in reducing cognitive decline. Studies suggest higher lutein levels are associated with better cognitive performance, including memory and processing speed, making pistachios a valuable addition to a diet aimed at supporting overall healthy aging.
Scott, T. M., et al. (2024). Pistachio consumption increases Macular Pigment Optical Density in healthy adults: a randomized controlled trial. Journal of Nutrition. doi.org/10.1016/j.tjnut.2024.10.022.