Dose-Response Effects of Pecan Consumption on Blood Lipid Profiles in Adults with Excess Body Weight and/or Dyslipidemia: a Randomized Controlled Trial.

BACKGROUND

Consuming ≥20% of daily energy from pecans improves blood lipids and reduces dyslipidemia but exceeds dietary recommendations. The benefits of lower doses remain unclear.

OBJECTIVES

This study aimed to examine the effects of pecan consumption at doses of 6%, 13%, and 20% of total energy needs on fasting and postprandial blood lipids in adults with excess body weight and/or dyslipidemia, compared with the control (CON). We hypothesized a dose-response relationship, with the 20% group showing the greatest lipid improvements, followed by 13% and 6%, and all would be better than the CON.

METHODS

This single-blind, randomized, controlled superiority trial enrolled 102 adults with excess body weight (BMI ≥28 kg/m2) or dyslipidemia. Participants were randomly assigned to 6% (n = 26), 13% (n = 26), or 20% (n = 25) pecan-intake groups, or to a CON (n = 25) that maintained a habitual, nut-free diet. Participants completed preintervention and postintervention visits, which included fasting lipid assessments and a high-fat meal challenge (17% of total energy), followed by 4-h postprandial blood draws.

RESULTS

Change in total cholesterol (TC), low-density lipoprotein cholesterol, apolipoprotein B, non-HDL cholesterol, and TC/HDL cholesterol ratio all decreased from preintervention to postintervention in the middle (MID) (-13.3 ± 3.4, -12.7 ± 3.3, -9.2 ± 2.3, -13.9 ± 3.2, and -0.3 ± 0.1 mg/dL, respectively; P < 0.05 for all) and HIGH (-12.7 ± 3.6, -11.9 ± 3.4, -7.8 ± 1.9, -13.8 ± 3.6, and -0.3 ± 0.1 mg/dL, respectively; P < 0.05 for all) groups compared with no change in the LOW or CON groups. Change from baseline postprandial nonesterified fatty acids (NEFAs) decreased from preintervention to postintervention in MID (P = 0.01) compared with no changes in CON, HIGH, or LOW (P > 0.05 for all). Fasting triglycerides (TGs), fasting NEFAs, and postprandial TGs did not differ between groups (P > 0.05 for all).

CONCLUSIONS

Pecan intake providing 20% and 13%, but not 6%, of daily energy improved fasting blood lipid profiles compared with the control, with postprandial NEFA reductions observed only at 13%. These findings offer the first evidence that moderate doses of daily pecan consumption confer cardioprotective benefits. This trial was registered at clinicaltrials.gov as NCT05949879 and available from: https://clinicaltrials.gov/study/NCT05949879. The date of initial trial registration was 18 July, 2023.