A recent research has confirmed that eating pistachios may trim down the body's response to the stress of everyday life. According to a Penn State study, elevated reactions to stressors can be reduced by including pistachios in the diet.
"A ten-year follow-up study of young men showed that those who had larger cardiovascular responses to stress in the lab, were more likely to contract hypertension later in life," says Dr Sheila G West, associate professor of biobehavioural health. "Elevated reactions to stressors are partly genetic, but can be changed by diet and exercise. Lifestyle changes can make the biological reactions to stress smaller."
West and her colleagues inspected the effects of pistachios on uniform stressors on participants who had high cholesterol, but normal blood pressure. They used a randomised, crossover controlled feeding study plan and all three diets included equal number of calories.
After a two-week run-in diet containing 35 per cent fat and 11 per cent saturated fats, each test diet lasted for four weeks during which time participants consumed only foods supplied by the study.
The researchers reported the results of this study at Experimental Biology 2007 on April 30 in Washington, D.C.
The diets given to the participants included a Step I Diet, a standard heart healthy diet with 25 per cent fat and 8 per cent saturated fat. The Step I Diet incorporated a diet containing 1.5 ounces of pistachios with 30 per cent total fat and 8 percent saturated fat and a diet containing 3 ounces of pistachios containing 34 per cent fat and 8 per cent saturated fat.
At the end of each four-week diet regime, the researchers measured blood pressure and total peripheral vascular resistance at rest and during two stress tests.
The two tests consisted of a physical test and a psychological test. The physical test consisted of putting one foot in a bucket of ice water for 2.5 minutes. The psychological test asked participants to listen to two numbers, add them in their head and say the answer. Then they were asked to pay attention to another number and add it to the second number they heard, not the sum they spoke.
"The ice water is a stimulus for the sympathetic nervous system, but it is very different form the stressors we encounter every day," says West. "We also wanted to see if the reaction occurred when the stress was non-physical, so we used the math test."
The researchers found that both pistachio containing diets abridged the stress effects on blood pressure, but that the 1.5 ounce pistachio diet reduced systolic blood pressure by 4.8 millimeters of mercury while the 3-ounce pistachio diet only reduced systolic blood pressure by 2.4 millimeters of mercury. The diets had no effect on normal, resting blood pressure.