Could a handful of pecans a day help your heart? A new clinical trial reveals that substituting snacks with pecans significantly enhances cholesterol levels and overall diet quality in adults at risk of cardiometabolic disease, without compromising blood vessel function.
Study: Consuming pecans as a snack improves lipids/lipoproteins and diet quality compared with usual diet in adults at increased risk of cardiometabolic diseases: a randomized controlled trial. Image Credit: Hong Vo / Shutterstock
In a recent study published in The American Journal of Clinical Nutrition, researchers investigated the impact of substituting snacks with pecans on vascular health, cardiometabolic risk factors, and diet quality in individuals at risk of cardiometabolic diseases.
In the United States, cardiometabolic diseases remain the leading causes of death, and poor diet quality is a modifiable risk factor for these diseases. Higher adherence to healthy dietary patterns is associated with a reduced risk of cardiometabolic diseases. However, adherence to healthy diets in the US is poor. Nutrient-rich snacks contribute to improved diet quality, whereas snacks high in saturated fat and added sugars contribute to poor diet quality.
Nuts are an integral part of healthy dietary patterns, and higher nut consumption is associated with a reduced risk of cardiovascular disease (CVD). Pecans contain higher levels of polyphenols than other nuts, including flavan-3-ol. Increased intake of flavan-3-ols has been shown to reduce the risk of cardiovascular mortality and coronary artery disease.
About the study
In the present study, researchers examined the effects of substituting usual snack foods with pecans on diet quality, vascular health, and cardiometabolic disease risk factors. Participants were recruited between July 2022 and December 2023. Eligible subjects were adults aged 25–70 years with obesity or overweight, who met at least one criterion for metabolic syndrome.
Participants were randomized to the pecan snack group or the usual diet group. The pecan group received 57 g/day of unsalted, raw pecans to replace their usual snacks, while the comparator group continued their regular diet. Participants completed daily questionnaires that documented their snack and pecan intake, changes in health status, and use of non-habitual medications.
All subjects were instructed to abstain from over-the-counter non-prescription medications and alcohol for 48 hours before testing. Central and peripheral blood pressure and carotid-femoral pulse wave velocity (cf-PWV) were measured on the testing day, and flow-mediated dilation (FMD) was measured on a separate day.
Blood samples were collected, and weight was measured on both test days. Glucose, glycated hemoglobin (HbA1c), lipids, lipoproteins, C-reactive protein (CRP), and insulin were also measured. Dietary intake was evaluated using self-administered 24-hour dietary recalls at baseline and weeks 6 and 12. Diet quality was also assessed using the Healthy Eating Index (HEI)-2020.
It is important to note that participants in the control group were also instructed to avoid nuts (other than the pecans provided to the intervention group) to prevent intervention contamination, which may have affected their diet quality scores.
Notably, baseline FMD values in both groups were already relatively high, indicating normal endothelial function. This may have contributed to the lack of effect seen in vascular outcomes. Additionally, the estimated daily flavan-3-ol dose from pecans (~9 mg) was much lower than doses shown in previous studies to benefit vascular function.
The improvement in lipid profiles observed in the pecan group may be attributed to dietary shifts, such as increased intake of unsaturated fats, fiber, and polyphenols—components known to support healthy cholesterol levels.
Findings
A total of 69 participants were assigned to each group. After 12 weeks, only 130 participants completed the endpoint testing. At baseline, 89% of subjects reported snack intake on the 24-hour dietary recall. The median baseline energy intake from snacks was 294 kcal for the whole cohort. There were no significant differences in FMD from baseline between the two groups.
Likewise, there were no significant group differences for vascular measures at week 12. Further, there were no differences in the effect of intervention by weight change status for vascular outcomes except pulse pressure. Subjects in the pecan group who experienced weight gain had a greater reduction in pulse pressure compared to those in the comparator group.
Moreover, pecan recipients showed higher reductions in total cholesterol, low-density lipoprotein (LDL) cholesterol, non-high-density lipoprotein (non-HDL) cholesterol, triglycerides, and total cholesterol-to-HDL cholesterol ratio. There were no significant group differences in the change from baseline for insulin, HDL cholesterol, CRP, HbA1c, or waist circumference. Specifically, there was no significant change in HDL cholesterol between groups.
No between-group difference in weight change was observed in the primary analysis; however, post hoc analyses revealed a modest but significant increase (~0.7 kg) in the pecan group. This modest weight gain may be due to incomplete energy substitution (i.e., pecans adding more calories than snacks replaced).
The mean HEI-2020 score was 56 points for both groups at baseline. After 12 weeks, the pecan group showed a 9.4-point increase compared to the control group on a usual diet. This improvement was partly due to a decrease in diet quality in the usual diet group during the study, possibly related to instructions to avoid nuts. The pecan group had no differences in HEI-2020 scores between weeks 6 and 12. Baseline macronutrient and energy intakes were similar between groups. At week 12, the pecan group had a higher intake of fiber and fats than the usual diet group.
The reductions in LDL cholesterol (about 7 mg/dL, or 6%) observed in the pecan group are considered clinically meaningful, as such reductions have been associated with a lower risk of future vascular events.
The study authors also note several limitations, including reliance on self-reported dietary intake, being underpowered to detect sex differences, and the potential for type I statistical error due to multiple comparisons.
The American Pecan Council funded the study, although the funder had no role in the study design, data collection, analysis, or interpretation.
Conclusions
In summary, 12 weeks of pecan intake instead of usual snacks did not affect FMD or other vascular measures in adults at risk of cardiometabolic diseases. However, pecan intake improved triglycerides and total, LDL, and non-HDL cholesterol compared to the usual diet group. There was no significant change in HDL cholesterol. Pecans also augmented diet quality, though a slight weight gain was observed in the pecan group. These findings suggest that replacing snacks with 57 g/day of pecans improves diet quality and lipids/lipoproteins, which may help alleviate the risk of cardiovascular disease (CVD) in individuals at risk of cardiometabolic diseases.
Journal reference:
- Hart TL, Kris-Etherton PM, Petersen KS. Consuming pecans as a snack improves lipids/lipoproteins and diet quality compared with usual diet in adults at increased risk of cardiometabolic diseases: a randomized controlled trial. The American Journal of Clinical Nutrition, 2025. DOI: 10.1016/j.ajcnut.2025.01.024