Pistachios may help improve eye health, new study finds

A new study¹ 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.²

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,³ 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 enhance of our understanding of the link between nutrition and eye health,,” said Dr. Tammy Scott, a research and clinical neuropsychologist and lead author of the study. “This is especially important as people age and face higher risks of vision impairment.”

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,⁴ 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. 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.⁵

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.⁵ 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.⁶

About the Study

The study, funded in part by the American Pistachio Growers and supported by the National Institutes of Health’s National Center for Advancing Translational Sciences award number UM1TR004398, involved 36 healthy adults who were randomly assigned to either a pistachio consumption group or a control group. Participants in the pistachio group consumed 2 ounces of pistachios daily, while the control group maintained their usual diets without pistachios. MPOD and blood levels of lutein were measured at baseline, 6 weeks, and 12 weeks. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

About American Pistachio Growers

American Pistachio Growers is a non-profit trade association representing more than 830 members who are pistachio growers, processors and industry partners in California, Arizona, Texas and New Mexico. American-grown pistachios are sold under many quality brand names internationally, so look for country of origin on packaging. For more information, visit AmericanPistachios.org.

References:

1. Scott TM, et al. Pistachio consumption increases macular pigment optical density in healthy adults: A randomized controlled trial. Journal of Nutrition. Published online October 17, 2024. DOI: 10.1016/j.tjnut.2024.10.022.
2. New Poll Places Fear of Vision Loss at the Top of Americans’ Health Concerns. Research to Prevent Blindness website. https://www.rpbusa.org/rpb/news-and-publications/news/latest/page-66/. Accessed October 18, 2024.
3. FoodData Central, FDC ID: 170185. USDA website. https://fdc.nal.usda.gov/fdc-app.html#/food-details/170185/nutrients. Accessed October 9, 2024.
4. Nutrient Intakes from Food and Beverages: Mean Amounts Consumed per Individual, by Gender and Age, What We Eat in America, NHANES 2017-2018. USDA website. www.ars.usda.gov/nea/bhnrc/fsrg. Accessed October 9, 2024.
5. Stringham JM, Johnson EJ, Hammond BR. Lutein across the lifespan: From childhood cognitive performance to the aging eye and brain. Curr Dev Nutr. 2019;3(7):nzz066.
6. Yagi A, Nouchi R, Butler L, Kawashima R. Lutein has a positive impact on brain health in healthy older adults: A systematic review of randomized controlled trials and cohort studies. Nutrients. 2021;13(6):1746.