Eating Pistachios May Reduce the Impact of Carbohydrates on Blood Sugar Levels

Newswise — “Heart disease remains the leading cause of death among both men and women and another 20 million people are living with diabetes each year – so these findings are very exciting and relevant,” said Dr. Cyril Kendall, lead researcher of the study and a professor in the University of Toronto's Department of Nutritional Sciences. “We know that controlling blood glucose levels is important for preventing and controlling diabetes and recent data indicate that it is also important in preventing heart disease. Controlling postmeal fluctuations in glucose appears to be particularly important. Pistachios have been shown to decrease risk factors for heart disease, however little has been known about the specific effects of pistachios on blood glucose until now. Our preliminary findings demonstrate that suppressing the glycemic (blood sugar) response of high carbohydrate foods may be part of the mechanism by which pistachios contribute to cardiovascular health and to the prevention and control of diabetes. More research is definitely warranted.”

“Glycemic Response of Pistachios – A Dose Response Study and Effect of Pistachios Consumed with Different Common Carbohydrate Foods on Postprandial Glycemia was presented today to more than 10,000 scientists at the Experimental Biology Conference in Washington, DC. The study is the first of its kind to examine the effects of pistachios and glucose levels in combination with carbohydrates. The research was led by University of Toronto’s Dr. Cyril Kendall and Dr. David Jenkins - researchers well known for their studies of the glycemic index which measures how rapidly sugars from foods are absorbed into the blood stream. Certain carbohydrates elevate blood sugar levels more quickly than other foods – like pistachios – that contain higher levels of protein, fiber and monounsaturated fat. In general, foods that do not quickly raise blood sugar are often considered healthier than their more processed counterparts.

Drs. Jenkins and Kendall and their research colleagues studied 10 healthy individuals who participated in a number of acute dietary studies over the course of two months. After an overnight fast, participants were given a one-, two- or three-ounce serving of pistachios alone or served with a slice of white bread and blood sugar levels were measured over a two-hour period. The findings suggest that consumption of pistachios with a carbohydrate-rich meal significantly lowered the d blood glucose response. As consumption of pistachios increased, the blood sugar lowering response was enhanced. In addition, when pistachios were consumed alone, the rise in blood glucose was minimal.

The researchers also monitored the effect of pistachios consumed with different common carbohydrate foods on postprandial glycemia, or blood sugar levels after eating. The addition of pistachios to a number of other commonly consumed carbohydrate-rich foods – such as mashed potatoes, pasta and rice – also resulted in significant reductions in the blood sugar response, compared to when these foods were eaten alone.

In July 2003, the U.S. Food and Drug Administration (FDA) approved a much-awaited qualified health claim for nuts and heart disease prevention. The claim states, "Scientific evidence suggests but does not prove that eating 1.5 ounces per day of most nuts, such as pistachios, as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease." According to the California Pistachio Commission, the University of Toronto’s research findings are important for individuals who are living a heart-healthy lifestyle and those that monitor their blood sugar levels.

“Most people with diabetes have other risk factors – such as high blood pressure and cholesterol that increase one's risk for heart disease and stroke. When combined with diabetes, these risk factors can add up to serious health problems,” explains Constance Geiger, PhD, RD, and consultant to the California Pistachio Commission. “Recent research has suggested that pistachios are a heart-healthy, high-protein snack. Now people have yet another reason to grab a handful – they may blunt the blood sugar response of meals and may be beneficial for assisting with long-term blood glucose control.”