Pistachios 'can protect the hearts of diabetics'

Ahandful of pistachio nuts twice a day protects the heart and arteries from harm caused by stress in diabetics, scientists found.

Just 150 of the nuts or three ounces a day resulted in people with Type 2 diabetes having more 'relaxed' and less narrower blood vessels, lower blood pressure especially when asleep and less strain on the heart after just four weeks.

The study by Pennsylvania State University said the nuts could reduce risk of heart disease but warned the nuts were not a cure for daily stress.

Professor of biobehavioural health and nutritional sciences Sheila West said: 'In adults with diabetes, two servings of pistachios per day lowered vascular constriction during stress and improved neural control of the heart.

'Although nuts are high in fat, they contain good fats, fibre, 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 published in the Journal of the American Heart Association involved two diets with the same number of calories.

After two weeks on the typical American diet - containing 36 per cent fat and 12 per cent saturated fats - participants were randomised to one of two test diets for the next four weeks.

One included a standard hearthealthy diet - 27 per cent fat and 7 per cent saturated fat - and a diet containing two servings per day of pistachios - about 3 ounces or 20 per cent of calories from pistachio nuts.

The pistachio diet contained 33 per cent fat and 7 per cent saturated fat with equal portions of salted and unsalted nuts.

Blood pressure and total peripheral vascular resistance at rest and during two stress tests - a cold water challenge by immersing one hand into icy water for two minutes and a confusing mental arithmetic test were then measured.

Prof West said: 'After the pistachio diet, blood vessels remained more relaxed and open during the stress tests.'

Researcher Katherine Sauder added: ' We found that systolic blood pressure during sleep was particularly affected by pistachios. Average sleep blood pressure was reduced by about 4 points and this would be expected to lower workload on the heart.'

But Prof West said: 'Our participants still felt frustrated and angry during the math test. 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.'

The researchers also recorded improvements in heart rate variability, a measure of how well the nervous system controls heart function.

These data indicated that pistachios increased the activity of the vagus nerve, an important part of the parasympathetic nervous system that can be damaged with diabetes.

Prof West said: ' 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.'