Pistachios reduce ravages of stress.

pistPenn State Researchers confirm that pistachios may reduce the body’s response to everyday stress. The study was published in the Journal of the American Heart Association and investigated the body’s response to two daily servings of pistachios.

“In adults with diabetes, two servings of pistachios per day lowered vascular constriction during stress and improved neural control of the heart,” said Sheila G. West, professor of bio-behavioral health and nutritional sciences. “Although nuts are high in fat, they contain good fats, fiber, potassium and antioxidants. Given the high risk of heart disease in people with diabetes, nuts are an important component of a heart healthy diet in this population.

The study consisted of a investigating the effects of pistachios on responses to standardized stress tasks in patients with well-controlled Type 2 diabetes who were otherwise healthy. The test subjects were randomized to different diets including a typical American diet with 35 % fat and 12% saturated fats and a standard heart-healthy diet with 27% fat and 7% saturated fat and a diet containing 2 daily services of pistachios.

The pistachio diet contained 33 percent fat and 7 percent saturated fat. Half of the nuts consumed each day were salted and half were unsalted. At the end of each four-week diet period, the researchers measured blood pressure and total peripheral vascular resistance at rest and administered two stress tests; a cold water challenge and a confusing mental arithmetic test.

“After the pistachio diet, blood vessels remained more relaxed and open during the stress tests,” West said.

“We found that systolic blood pressure during sleep was particularly affected by pistachios,” she said. “Average sleep blood pressure was reduced by about 4 points and this would be expected to lower workload on the heart.”

Pistachios reduced the body’s response to stress. “Our participants still felt frustrated and angry during the math test,” West noted. “The pistachio diet reduced their bodies’ responses to stress, but nuts are not a cure for the emotional distress that we feel in our daily lives.”

Sauder added: “As in our last study of pistachios, we did not see lower blood pressure in the laboratory setting with this dose of nuts. However, we were surprised and pleased to see that 24-hour ambulatory blood pressure was lower after the pistachio diet.”

The researchers also noted improvements in heart rate variability. “If sustained with longer term treatment, these improvements in sleep blood pressure, vascular response to stress and vagal control of the heart could reduce risk of heart disease in this high risk group,” West said.


K. A. Sauder, C. E. McCrea, J. S. Ulbrecht, P. M. Kris-Etherton, S. G. West. Pistachio Nut Consumption Modifies Systemic Hemodynamics, Increases Heart Rate Variability, and Reduces Ambulatory Blood Pressure in Well-Controlled Type 2 Diabetes: a Randomized Trial. Journal of the American Heart Association, 2014; 3 (4): e000873 DOI: 10.1161/JAHA.114.000873

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