A new study by researchers at the Friedman School of Nutrition Science and Policy at Tufts University has found that daily consumption of pistachios can significantly improve eye health by increasing macular pigment optical density (MPOD) due to the plant pigment lutein, a key factor in the Increased protection for the eyes from blue (visible) light and age-related damage.
The randomized controlled trial showed that consuming 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 compared to consuming a normal diet alone . MPOD is an important indicator of eye health because it protects the retina and is associated with a reduced risk of age-related macular degeneration (AMD), a leading cause of blindness in older adults.
The findings of this research are timely because, according to a national survey by the American Foundation for the Blind, Americans are more afraid of vision loss than other serious health problems.
Key findings
- Increased MPOD: Participants who consumed pistachios daily experienced a significant increase in MPOD after just 6 weeks, with the effect lasting throughout the entire 12-week study.
- Natural source of lutein: Pistachios are the only nuts that provide a measurable source of lutein, a powerful antioxidant that helps protect the eyes.
- Potential for AMD prevention: The study suggests that regular consumption of pistachios could provide a natural nutritional approach to reducing the risk of AMD.
Our results suggest that pistachios are not only a nutritious snack, but may also provide significant eye health benefits. This is particularly important as people age and are at greater risk of visual impairment.”
Dr. Tammy Scott, 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 crucial role in maintaining eye health by filtering blue light and acting as an antioxidant in the eye. The study found that eating pistachios nearly doubled participants’ daily lutein intake, which is typically very low in most American diets, and significantly increased plasma levels of lutein.
Dr. Scott explains that participants in the study were selected so that they habitually had a low starting intake of lutein in their diet, and just 2 ounces per day quickly increased blood lutein levels in just 6 weeks. “By simply including a handful of pistachios in your diet, you can improve the absorption of lutein, which is crucial for protecting your eyes,” notes Dr. Scott. She adds that pistachios are a source of healthy fat and may allow the lutein from pistachios to be better absorbed by the body.
The study provided about 1.6 mg of lutein from pistachios, which would be enough to double the average daily intake of lutein, which belongs to a class of plant pigments known as xanthophylls, in U.S. adults.
More comprehensive health benefits of lutein
The lutein found in pistachios not only supports eye health but can also improve brain function. “Lutein crosses the blood-brain barrier and can help reduce oxidative stress and inflammation,” notes Dr. Elizabeth Johnson, a co-investigator on the study.
As in the eye, lutein accumulates selectively in the brain and may play a role in reducing cognitive decline. Studies suggest that higher levels of lutein 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.
Source:
American pistachio growers
Magazine reference:
Scott, T.M., et al. (2024). Pistachio consumption increases macular pigment optical density in healthy adults: a randomized controlled trial. Nutrition magazine. doi.org/10.1016/j.tjnut.2024.10.022.