Study Confirms Key Antioxidants in Pistachios

Results of new research presented at the American Society of Nutrition in San Diego contributes to the increasing amount of scientific evidence that underscores the health benefits of eating pistachios on a daily basis.

A study conducted at the Institute of Food Research (IFR) in the United Kingdom in conjunction with the University of Messina, Italy, confirms that key nutrients in pistachios are released during digestion and thus able to be absorbed in the gastrointestinal tract. Polyphenols, carotenoids (vitamin A) and tocopherols (vitamin E), all with strong antioxidant qualities were quantified in the study.

Giuseppina Mandalari, Ph.D., research scientist at IFR and lead investigator says, "These results are significant as they are the first that show when the bioactive compounds in pistachios are released during digestion and are available to be taken up by the body." She continues, "This research indicates these nutrients would contribute to the beneficial relationship between pistachio consumption and health-related outcomes, such as heart disease."

"In addition, these results support the findings of the 2010 nationally-published study¹ and trials by researchers at Penn State University that addressed the positive effect of antioxidants from pistachios on LDL cholesterol," added Constance J. Geiger, Ph.D., R.D. who serves as a nutrition research consultant with the American Pistachio Growers.

This new data helps connect the dots between the bioactive compounds in pistachios, their release into the digestive tract and absorption into the blood. The Penn State study showed an increase in lutein and gamma-tocopherol in the blood was related to a decrease in oxidized LDL (bad) cholesterol, when pistachios were eaten daily, thereby contributing to a reduced risk of heart disease.

In the present study, researchers tested raw, roasted and salted pistachios and muffins made with raw pistachios in an in vitro model of digestion which simulates the human stomach and small intestine. The bioaccessibility of the nutrients in pistachios was evaluated at various stages during the digestion process. Each measurement was performed in triplicate for the three tested models.

No significant differences in bioaccessibility of the bioactive compounds were noted between raw and roasted salted pistachios in the stomach and small intestine. Only the presence of baked muffin limited the release of protocatechuic acid and luteolin in the gastric and duodenal compartments.