When it comes to keeping your heart healthy and ticking like a well-oiled machine, all you have to do is eat a handful of pistachios every day.
The finding is based on a new research conducted by James N. Cooper M.D., of George Mason University and Michael J. Sheridan, Sc.D., of Inova Fairfax Hospital, who found that a 4-week pistachio diet, containing moderate amounts of heart healthy fat, improves risk factors for heart disease with no weight gain.
The two researchers noted that in people with moderately high cholesterol levels, a daily diet consisting of 15 percent of calories from pistachios (about two to three ounces or one to two handfuls of kernels) over a four-week period favourably improved some blood lipid levels.
The finding adds to a growing body of evidence that pistachios may offer protective benefits.
Dr Cooper said that the study also challenged the previously held belief that a low-fat diet is best for heart health.
"These results are exciting because the research indicates that adding pistachios to the daily diet can help protect the heart without a dramatic dietary lifestyle change," said Dr. James Cooper.
"This research challenges the previously-held belief that a low-fat diet is best for heart health. Studies now show that 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. What's more, we noted very good compliance and a positive response from participants during the four-week period," he said.
As a part of the study, the researchers carried out a randomised crossover trial in which 15 free-living people with moderately high blood cholesterol (greater than 210 mg/Hg) were given a diet where 15 percent of daily calories came from pistachios to see if it would have a significant impact on their blood lipid levels.
All subjects consumed their normal diets during a five-day baseline period. Then, half the subjects were randomised to the pistachio diet for four weeks followed by four weeks on the regular diet; the other half followed the diets in reverse order.
Subjects were instructed to substitute the pistachio nuts for normally consumed high-fat snacks. Subjects who did not normally consume high-fat snacks were asked to substitute pistachio nuts as fat calories. Otherwise, subjects consumed their normal diets.
The researchers found that not only did adding pistachios in the diet favourably improved some blood lipid levels, but the subjects also showed no changes in blood pressure, body mass index, or weight gain; further supporting previous studies which have also demonstrated no weight gain from the addition of pistachios to a daily diet.
Nut consumption, in general, is associated with a lower body mass index and has not been shown to cause weight gain.
Most of the fat in pistachios - almost 90 percent - is "good" or monounsaturated fat, which can lower blood cholesterol along with heart disease. Of all snack nuts, pistachios offer the highest level of phytosterols, and are a powerful source of fiber, both of which reduce the absorption of cholesterol from the diet. Pistachios make a wise snack choice as they are contain dense levels of eight nutrients including thiamin, vitamin B6, copper, manganese, potassium, fibre, phosphorus and magnesium.
High levels of most blood lipids increase the risk of developing both heart disease and stroke while lowering blood lipid levels has been shown to reduce the risk. Lipids join with protein in the blood to form lipoproteins, known as cholesterol.
The research appears in the Journal of the American College of Nutrition.