November 15, 2016
2 min read

High-monounsaturated fatty acid diets reduce fat mass, metabolic risk factors

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Patients whose diets were high in monounsaturated fatty acids saw a reduction in obesity and risk factors for metabolic syndrome compared with those assigned diets with higher polyunsaturated fatty acid content, according to results of a randomized feeding study.

“Almost 40% of U.S. adults have metabolic syndrome based on the International Diabetes Federation definition. Weight loss is the primary treatment for metabolic syndrome,” Xiaoran Liu, PhD, of the department of nutritional sciences at The Pennsylvania State University, University Park, Pennsylvania, and colleagues wrote. “Evidence is emerging that demonstrates beneficial effects of dietary monounsaturated fatty acids in regulating body weight and cardiometabolic risk factors. Our understanding of the role that monounsaturated fatty acids play in cardiometabolic disease risk reduction is in the early stages, and further research is needed to clarify the specific effects that monounsaturated fatty acids have on central obesity, which is causally related to other metabolic syndrome criteria.”

Researchers performed a randomized, controlled feeding study on 101 adults with obesity in the U.S. and Canada. Participants were randomly assigned to five low-calorie diets including five different treatment oils: canola DHA, canola oleic, canola, corn/safflower and flax/safflower. Mean age was 49.5 years, and mean BMI was 29.4 kg/m2. All patients had at least one criterion for metabolic syndrome; 39 had high blood pressure, 44 had elevated triglycerides, 34 had elevated fasted glucose and 49 had low HDL cholesterol.

Liu and colleagues wrote that overall, android fat mass was correlated with triglyceride levels (r = 0.27; P = .04), C-reactive protein (r = 0.28; P = .04), systolic BP (r = 0.32; P = .02) and diastolic BP (r = 0.32; P = .019). Participants assigned to the canola and canola oleic diets experienced a reduction in android fat mass (3.1 kg; P = .026 and 3.09 kg; P = .03, respectively) compared with the flax/safflower oil diet (3.2 kg), Liu and colleagues reported. This was particularly true for men.

Decrease in abdominal fat was associated with a decrease in BP in the canola diet group (systolic BP: r = 0.26; P = .062; diastolic BP: r = 0.38; P = .0049), as well as the canola oleic diet group (systolic BP: r = 0.39; P = .004; diastolic BP: r = 0.45; P = .0006). Patients assigned to the canola oleic diet also had a decrease in triglycerides, which was associated with decreased fat mass (r = 0.42; P = .002).

“In summary, short-term consumption of diets high in monounsaturated fatty acids provided by canola oil and canola oleic oil was associated with a reduced android fat mass in participants with or at risk for metabolic syndrome,” Liu and colleagues wrote. “These changes were associated with favorable shifts in cardiometabolic risk factors. Importantly, our findings provide evidence for a beneficial effect of dietary monounsaturated fatty acids in lowering cardiometabolic risk that we suggest is mediated by a decrease in android fat mass.” – by Andy Polhamus

Disclosure: Liu reports no relevant financial disclosures. Please see the full study for a complete list of all other authors’ relevant financial disclosures.