Canola oil and high-oleic canola oils can lower abdominal fat when used in place of other selected oil blends, according to a team of American and Canadian researchers. The researchers also found that consuming certain vegetable oils may be a simple way of reducing the risk of metabolic syndrome, which affects about one in three U.S. adults and one in five Canadian adults.
"The monounsaturated fats in these vegetable oils appear to reduce abdominal fat, which in turn may decrease metabolic syndrome risk factors," said Penny Kris-Etherton, Distinguished Professor of Nutrition, Penn State.
In the randomized, controlled trial, 121 participants at risk for metabolic syndrome received a daily smoothie containing 40 grams (1.42 ounces) of one of five oils as part of a weight maintenance, heart-healthy, 2000-calorie per day diet. Members of the group had five risk factors characterized by increased belly fat, low "good" hdl cholesterol and above average blood sugar, blood pressure and triglycerides that increase the risk of heart disease, stroke and type 2 diabetes. The researchers repeated this process for the remaining four oils.
The results were presented at the American Heart Association's EPI/NPAM 2013 Scientific Sessions in New Orleans.
Results showed that those who consumed canola or high-oleic canola oils on a daily basis for four weeks lowered their belly fat by 1.6 percent compared to those who consumed a flax/safflower oil blend. Abdominal fat was unchanged by the other two oils, which included a corn/safflower oil blend and high-oleic canola oil enriched with an algal source of the omega-3 DHA. Both the flax/safflower and corn/safflower oil blends were low in monounsaturated fat.
According to the American Heart Association, many of the factors that contribute to metabolic syndrome can be addressed by a healthy diet, exercise and weight loss, which can significantly reduce health risks of this condition.
"It is evident that further studies are needed to determine the mechanisms that account for belly fat loss on a diet high in monounsaturated fatty acids," said Kris-Etherton. "Our study indicates that simple dietary changes, such as using vegetable oils high in monounsaturated fatty acids, may reduce the risk of metabolic syndrome and therefore heart disease, stroke and type 2 diabetes."
Other authors on the paper include Peter Jones and Shuaihua Pu of the University of Manitoba in Winnipeg; Sheila West, Xiaoran Liu, Jennifer Fleming and Cindy McCrea of Penn State; Benôit Lamarche and Patrick Couture of Laval University in Quebec; and David Jenkins of the University of Toronto. The government of Canada, the Canola Council of Canada and Dow Agrosciences funded this research.