A 12-week randomized controlled trial found that replacing usual snacks with 57 g per day of pecans may lead to improvements in lipid profiles and diet quality among adults at risk of cardiometabolic disease.

In the study, published in The American Journal of Clinical Nutrition, researchers enrolled 138 adults with a mean age of 46 years and mean BMI of 29.8 kg/m² with at least 1 criterion for metabolic syndrome. The participants were randomly assigned to either a pecan group or a usual diet control group. The intervention group received preportioned, unsalted pecans and replaced their typical snacks. The control group maintained their usual diet. The intervention didn't affect endothelial function or other vascular measures.

After 12 weeks, the pecan group showed the following changes compared with the control group:

• Total cholesterol decreased by 8.1 mg/dL.
• Low-density lipoprotein (LDL) cholesterol decreased by 7.2 mg/dL
• Non–high-density lipoprotein (HDL) cholesterol decreased by 9.5 mg/dL.
• Triglycerides decreased by 16.4 mg/dL.

There were no statistically significant changes in HDL cholesterol, insulin, glucose, HbA1c, C-reactive protein (CRP), or waist circumference between groups. A modest weight increase of 0.7 kg was observed in the pecan group, noted Tricia L. Hart, of the Department of Nutritional Sciences at Pennsylvania State University, and her colleagues.

Diet quality was assessed using the Healthy Eating Index–2020 (HEI-2020). The pecan group scored 9.4 points higher compared with the control group at 12 weeks. Improvements were noted in components including total protein foods, seafood and plant proteins, fatty acids, and added sugars.

Flow mediated dilation (FMD), the study’s primary endpoint, didn't change significantly between groups (mean difference = 0.08%). No statistically significant differences were observed in carotid-femoral pulse wave velocity or blood pressure. Vascular outcomes did not vary significantly by sex or weight change, except for a greater decrease in pulse pressure among participants in the pecan group who gained weight (−3.22 mmHg).

Participants were aged 25 to 70 years and had overweight or obesity (BMI = 25–40 kg/m²). Patients with cardiovascular disease, diabetes, or recent tobacco use were excluded. Compliance was high; participants reported consuming their assigned snacks for nearly all study days.

At 12 weeks, the pecan group had higher intake of total fat, monounsaturated fat (13.7 g), polyunsaturated fat (7.4 g), and dietary fiber (3.3 g). They also had lower carbohydrate intake and lower saturated fat intake at specific timepoints.

Full disclosure can be found in the study.