• Eating 2 oz. of pistachios daily for 12 weeks significantly increased macular pigment optical density.
• Serum lutein concentration also improved in the group that consumed pistachios.

Consuming 2 oz. of pistachios daily for 12 weeks significantly increased macular pigment optical density in healthy adults and may be an effective dietary intervention to preserve eye health, according to researchers.

“This study demonstrates that a dietary intervention with pistachios is efficacious in increasing MPOD,” Tammy M. Scott, PhD, MPhil, MS, research assistant professor at the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University, and colleagues wrote in The Journal of Nutrition. “Pistachios are unique as they are the only tree nut to contain substantial amounts of lutein, but the average consumption of tree nuts is low in the U.S. compared to the FDA-qualified health claim.

To evaluate the effect of daily consumption of pistachios on macular pigment optical density (MPOD), Scott and colleagues enrolled 36 healthy adults (average age, 59.5 years; 58% women; average BMI, 25.6 kg/m²), whose screening examinations at Tufts Clinical and Translational Research Center included medical history, MPOD measurement, dietary intake of lutein and zeaxanthin, height and weight. Eligible participants had low lutein and zeaxanthin intake and low baseline MPOD, which was measured using heterochromatic flicker photometry.

The researchers randomly assigned participants to one of two groups: an intervention group that consumed 2 oz. of shelled pistachios per day with their usual diet or a control group that consumed their usual diet alone. At weeks 6 and 12, MPOD, lutein, and zeaxanthin, and weight were measured, with fasting blood samples also collected at week 12.

According to the results, there was a significant increase in MPOD in the intervention group by week 6, which was maintained through week 12. MPOD did not significantly change in the control group throughout the study period.

Similarly, serum lutein concentrations increased in the intervention group at week 12 and were unchanged in the control group.

“Our findings suggest that inclusion of pistachio nuts in a healthy diet could be an effective dietary strategy for promoting eye health,” Scott and colleagues wrote. “Future studies are needed to evaluate dose-response as well as efficacy in other populations and with other measures of eye health beyond MPOD.”

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Sources/Disclosures

Source:  Scott TM, et al. J Nutr. 2024;doi:10.1016/j.tjnut.2024.10.022.

Disclosures: This project was supported by the American Pistachio Growers and NIH. Scott reports financial support from American Pistachio Growers. Please see the study for all other authors’ relevant financial disclosures.

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