Pecans may improve cardiometabolic health markers in overweight, obese adults

A study published in the journal Nutrients suggests that eating a handful of pecans every day may improve certain markers of cardiometabolic disease risk, including insulin sensitivity.

In this randomized, placebo-controlled feeding study of 26 overweight or obese men and women (21 men and five women, aged 45+), the research team compared the effects of a pecan-rich diet to a control diet that contained the same amount of calories, fat, and fiber, but without the pecans. The control diet resembled the average American diet—low in fruit, vegetables, fiber, and omega-3 fatty acids, and high in nutrient-poor, calorie-dense foods. All meals were provided to the subjects, including the pecans (about 1.5 oz a day or 15% of total calories), which were ground and incorporated into various recipes, such as muffins, meatballs, and coating for chicken.

The study participants followed either the pecan diet or the control diet for four weeks. A two-week washout period took place before the groups switched to the opposite diet for four weeks. Evaluations were conducted at the start of the study and at the end of each four-week feeding period.

After four weeks on the pecan-rich diet, overall outcomes showed the study participants had statistically significant greater reductions in serum insulin, insulin resistance, and pancreatic beta cell function, compared to the control diet. Although both total and LDL cholesterol were lower following the pecan diet, their magnitude of change compared with the control diet was not statistically significant, which the authors say may be due to the lower dose of pecans compared with other tree nut studies or the higher prevalence of obesity among the participants. Other markers of cardiometabolic risk, including serum glucose, systolic blood pressure, and diastolic blood pressure also had greater reductions among participants on the pecan diet compared to the control diet, but these results did not reach statistical significance.

The researchers also simultaneously assessed five clinically relevant markers of cardiometabolic risk (including blood lipids, glucoregulation, and insulin), and found that the pecan diet had a statistically significant effect on insulin related markers associated with cardiometabolic risk. Additionally, there were subgroup differences noted by gender and glucose levels that modified the effects of the pecan diet.

“Our study suggests that making one small change, such as eating a handful of pecans daily and displacing saturated fat in the typical American diet has the potential to make a difference,” said Diane McKay, lead researcher and assistant professor at Tufts University School of Medicine. “The limitation of our study is its small size and duration. We found that consuming pecans improved certain markers in some at-risk individuals, but larger and longer studies are needed to determine whether pecans could reduce risk for cardiovascular disease and type 2 diabetes. More research could also reveal the specific effects of bioactive compounds in pecans and their potential mechanisms of action.”

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