Incorporating pistachios into the diet can significantly reduce cholesterol and help to prevent narrowing of the arteries, research suggests.

Nuts have a reputation as being salty, fatty and high in calories. In fact, they contain protein, fibre and in many cases their fats are of the healthy type. In 2003 the US Food and Drug Administration allowed nuts — including walnuts, peanuts, almonds and pistachios — to carry a “qualified health claim” asserting there was evidence that they could lower the risk of heart disease, because of their effects on cholesterol.

The latest trial, focusing on pistachios, adds to the evidence by showing that one or two handfuls of the nuts can reduce cholesterol levels. Volunteers who ate three ounces (85g) of pistachios a day for one month lowered their total blood cholesterol by 8.4 per cent.

Crucially, levels of “bad” cholesterol, low-density lipoprotein (LDL), went down by 11.6 per cent, while the balance between LDL and “good” cholesterol, high-density lipoprotein (HDL), was also changed. Participants on the pistachio diet had less LDL relative to HDL after four weeks.

The volunteers did not simply add pistachios to their normal diet. Instead, they were put on diets that lowered the total fat they consumed, and also on lower-fat diets that incorporated either 1.5 or 3oz of pistachios a day.

The findings were presented at Experimental Biology, a meeting in Washington DC.

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