A new study published on May 10th in the
Archives of Internal Medicine confirms that eating nuts like pistachios may lower total and LDL (bad) cholesterol, supporting evidence that regular nut consumption can lower the risk of coronary heart disease.
The study—led by Dr. Joan Sabate and colleagues at Loma Linda University (Loma Linda, CA)—pooled analysis from 25 studies conducted in seven countries and included results from 583 people with normal and slightly elevated cholesterol levels, who were not on cholesterol-lowering medication. The research support was provided by Loma Linda University and the International Tree Nut Council Nutrition Research & Education Foundation.
"Nuts, such as pistachios, are continually proving their worthy place in the daily diet due to their numerous health benefits," said Dr. Constance Geiger, nutrition expert for the Western Pistachio Association (WPA). "This wide-ranging study further shows that when nuts such as pistachios, are eaten on a regular basis, they help lower total and LDL (bad) cholesterol thereby lowering the risk of heart disease."
Researchers at Loma Linda University found that those who ate about 2.4 ounces of nuts, such as pistachios, per day had an average reduction in total cholesterol and LDL cholesterol of 5.1% and 7.4%, respectively. A 7.4% reduction in bad cholesterol may help lower the risk of heart disease by a similar amount (7.4%). Furthermore, the LDL-to-HDL ratio and total cholesterol-to-HDL ratio were also significantly lowered in subjects; 8.3% and 5.6%, respectively. These results may be even more powerful predictors of lower cardiovascular risk. Notably, the effect of nuts was dose-related, showing that the more nuts that were eaten the larger the effect on blood lipids.
Recent studies on pistachios further confirm these findings. Results from an ongoing study conducted at Penn State University (Gebaurer et al 2008) suggest a dose response of pistachios on blood cholesterol levels.
Compared to the control diet, a diet including 20% of calories from pistachios lowered LDL cholesterol about 12% and the diet containing 10% of calories from pistachios lowered LDL cholesterol by 9%. These results indicate the risk of heart disease may be lowered 10 to 12%. Furthermore, similar to the Sabate study, the 10% and the 20% pistachio diets, respectively, showed a dose-response lowering (P less than 0.05) of the LDL-to-HDL ratio (-3% and -11%) and the total cholesterol-to-HDL ratio (-1% and -8%).
Importantly, the researchers noted that the reduction in LDL cholesterol observed was seven times greater than would be expected from only the fatty acid profile of pistachios. They suggest that the lipid-lowering effects not only reflect the fatty acid profile of the diet, but also are the result of other bioactive substances in pistachios, perhaps phytosterols and fiber. Pistachios provide 3 grams of fiber in one ounce.