The scientists have found that pistachios bring down levels of "bad" cholesterol in the blood, as they contain an antioxidant called lutein, also found in fruit and leafy green vegetables which cuts the build-up of bad cholesterol in the arteries.
"Pistachios are very healthy in moderation. A handful a day is very easily incorporated into the diet and they are less calorific than peanuts as you have to take the shell off," the Daily Express quoted nutritionist Angela Dowden, as saying.
To reach the conclusion, scientists at Pennsylvania State University and Oklahoma Medical Research Foundation chose 28 adults whose average bad cholesterol level was "borderline high".
They first gave them a diet rich in cheese, oil and butter. Then they switched to low-fat diets before incorporating pistachios.
Bad cholesterol levels dropped by 12 per cent when two daily servings of pistachios were eaten. Good cholesterol levels did not change.
The study has been published in The American Journal of Clinical Nutrition.
However, nutritionists warn that eating too many and gaining extra weight will not protect your heart.