Tim Hearden/Capital Press
SACRAMENTO — Almond and pistachio grower groups say recent research showing the two nuts have fewer calories than previously believed has reinforced their image as healthy snacks.
U.S. Department of Agriculture scientists have improved the method for estimating calories in tree nuts, paying closer attention to how the digestive process removes fat from the body.
Researchers initially found that the caloric value of pistachios has likely been overestimated by about 5 percent because the fat from the nuts wasn’t completely absorbed by the intestinal tract. Even better results were later discovered for almonds, which provide about 20 percent fewer calories than originally thought.
The modified method should also work well for other foods, according to the scientists from the Agricultural Research Service.
Industry representatives characterize the studies as “a big deal,” adding that they have long questioned the nuts’ high-calorie label.
“In our case, we were already one of the lowest-fat nuts,” said Judy Hirigoyen, director of global marketing for the Fresno, Calif.-based American Pistachio Growers. She said pistachios are promoted as a snack for people who want to control their weight.
“I think people look to tree nuts for more than the calories or energy they provide but for phytonutrients,” she said, referring to natural disease-fighting chemicals found in plants. “I think in the case of pistachios and almonds, when people take a look at the phytonutrients and plant-based protein, it’s a bargain. They’re both a bargain food.”
The ARS detailed the researchers’ human clinical trial to compute the number of calories in almonds in the September issue of Agricultural Research magazine. The initial pistachio study by ARS physiologists David Baer and Janet Novotny was published in the British Journal of Nutrition in 2011.
Almonds and pistachios have joined walnuts in a production and value boom in California in recent years. About 98 percent of the nation’s pistachios are grown in the Golden State, where almond orchards account for about 80 percent of the world’s production.
The calorie studies continue a string of recent research that have reinforced the nuts’ healthful qualities. In 2011, for instance, a scientific review by Pennsylvania State University researchers suggested that almonds’ high concentration of fiber, fatty acids and other nutrients may reduce a consumer’s risk of heart disease.
Almonds and pistachios fared well in the 2010 Dietary Guidelines for Americans, which encourages people to eat more plant-based sources of protein.
In their studies, Baer and Novotny fed groups of healthy adults varying amounts of nuts for 18 days and collected and analyzed urine and stool samples from the volunteers. Novotny, who is also a mathematician, wrote a series of algebraic equations to compare the calories in the foods that were fed to subjects and the same foods’ excreted remains.
The researchers maintained that the fat within some hard foods is not completely absorbed because it’s difficult to digest the food’s cell walls, which contain the fat, an ARS news release explained.
“For almonds and pistachios, our super foods just got a little more super,” Hirigoyen said.
ARS article: An Improved Method to Estimate Calories: http://www.ars.usda.gov/is/AR/archive/sep13/calories0913.htm