"A diet with a moderate amount of healthful monounsaturated fat, like the kind found in pistachios, is a more effective way to prevent heart disease than reducing overall fat intake," said Dr James Cooper of George Mason University who conducted the new study.

This follows a 2005 study, published by the Journal of Agriculture and Food Chemistry (Vol 53, pp. 9436-9445), which proved pistachios held the richest source of phytosterols in snack foods, believed to reduce blood cholesterol.

The new study claims that a daily four-week diet consisting of 15 percent of calories from pistachios improved blood serum lipid levels, 'and may reduce risk of coronary disease'.

Subjects involved in the study had blood cholesterol levels greater than 210mg/dL, compared to normal levels of under 200mg/dL. BMI, blood pressure and nutrient intake were measured throughout.

The results also showed that there was no change in blood pressure, BMI or weight levels in those on the pistachio diet, supporting recent research that pistachios are a healthy snack option.

Global demand for cholesterol reducing phytosterols is estimated to exceed 10,000 tons by 2008, giving a potential market value of $200-$250m (€150 - €190m). The world market for pistachios is over 500,000 tonnes per annum.

Source: Journal of the American College of Nutrition

Volume 26, Number 2, 141-148 (2007)

"Pistachio Nut Consumption and Serum Lipid Levels"

Authors: M J Sheridan, J N Cooper, M Erario, and C E Cheifetz