Effect of nut consumption on blood lipids: An updated systematic review and meta-analysis of randomized controlled trials

Pecan Intake Improves Lipoprotein Particle Concentrations Compared with Usual Intake in Adults at Increased Risk of Cardiometabolic Diseases: A Randomized Controlled Trial

BACKGROUND

Pecan consumption consistently improves lipoproteins, but less research has investigated the effect of pecans on lipoprotein subfractions.

OBJECTIVES

The aim was to investigate the effect of substitution of usual snack foods with 57 g/d of pecans on lipoprotein particle subfractions and apolipoproteins compared with continuing usual intake after 12 wk. Exploratory analyses evaluated effects on early markers of insulin resistance including the Lipoprotein Insulin Resistance Index (LP-IR), Diabetes Risk Index, and GlycA.

METHODS

A 12-wk, randomized, 2-armed parallel trial in adults at risk of cardiometabolic disease was conducted. Participants were instructed to either consume 57 g/d of pecans in place of usual snacks or to continue their usual intake. Plasma samples collected at baseline and 12 wk were analyzed for lipoproteins, apolipoproteins, and GlycA by proton nuclear magnetic resonance spectroscopy. Between-group differences in the change from baseline were evaluated with linear regression.

RESULTS

In total, 138 participants were randomly assigned (n = 69 per group) and 130 participants (pecan group n = 62; usual diet group n = 68) completed the trial. The pecan group had a greater reduction from baseline in the concentrations of apolipoprotein B (apoB) [-4.38 mg/dL; 95% confidence interval (CI): -8.02, -0.73], total low-density lipoprotein particles (-75.3 nmol/L; 95% CI: -144, -6.93), total triglyceride-rich lipoprotein particles (TRL-P) (-20.4 nmol/L; 95% CI: -33.8, -7.03), large (-1.47 nmol/L; 95% CI: -2.69, -0.26) and small (-11.3 nmol/L; 95% CI: -22.4, -0.27) TRL-P and the LP-IR (-4.42 points; 95% CI: -8.14, -0.69), and greater increases from baseline in the concentration of large high-density lipoprotein particles (0.35 μmol/L; 95% CI: 0.07, 0.63) compared with the usual diet group.

CONCLUSIONS

Incorporating 57 g/d of pecans into the diet in place of usual snacks for 12 wk improved apoB, atherogenic lipoprotein subfractions, and the LP-IR in adults at risk of cardiometabolic diseases. This trial was registered at clinicaltrials.gov as NCT05071807.

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

BACKGROUND

The vascular and cardiometabolic effects of pecans are relatively understudied.

OBJECTIVES

The aim was to examine how substitution of usual snack foods with 57 g/d of pecans affects vascular health, risk factors for cardiometabolic diseases, and diet quality, compared with continuing usual intake in individuals at risk of cardiometabolic diseases.

METHODS

A 12-wk single-blinded, parallel, randomized controlled trial was conducted. Adults with ≥1 criterion for metabolic syndrome who were free from cardiovascular disease and type 2 diabetes were included. Participants were provided with 57 g/d of pecans and instructed to replace the snacks usually consumed with the provided pecans. The control group was instructed to continue consuming their usual diet. Flow-mediated dilation (FMD),primary outcome, along with blood pressure, carotid-femoral pulse wave velocity (cf-PWV), lipids/lipoproteins, and glycemic control were measured at baseline and following the intervention. Participants completed 3 24-h recalls at 3 time points (baseline, week 6, and week 12) during the study (9 recalls in total). The Healthy Eating Index-2020 (HEI-2020) was calculated to assess diet quality.

RESULTS

In total, 138 participants (mean ± SD; 46 ± 13 y, 29.8 ± 3.7 kg/m2) were randomly assigned (69 per group). No between-group differences in FMD, cf-PWV, or blood pressure were observed. Compared with the usual diet group, pecan intake reduced total cholesterol (-8.1 mg/dL; 95% confidence interval [CI]: -14.5, -1.7), LDL cholesterol (-7.2 mg/dL; 95% CI -12.3, -2.1), non-HDL-cholesterol (-9.5 mg/dL; 95% CI -15.3, -3.7), and triglycerides concentrations (-16.4 mg/dL; 95% CI -30.0, -2.9). Weight tended to increase in the pecan group compared with the usual diet group (0.7 kg; 95% CI -0.1, 1.4). The HEI-2020 increased by 9.4 points (95% CI 5.0, 13.7) in the pecan group compared with the usual diet group.

CONCLUSIONS

Replacing usual snacks with 57 g/d of pecans for 12-wk improves lipids/lipoproteins and diet quality but does not affect vascular health in adults at risk of cardiometabolic disease. This trial was registered at clinicaltrials.gov as NCT05071807.

Effects of Longer-Term Mixed Nut Consumption on Lipoprotein Particle Concentrations in Older Adults with Overweight or Obesity

BACKGROUND

Recently, we reported that longer-term mixed nut intake significantly reduced serum total and low-density lipoprotein (LDL)-cholesterol, but these markers may not fully capture lipoprotein-related cardiovascular disease (CVD) risk.

OBJECTIVES

This randomized, controlled, single-blinded, crossover trial in older adults with overweight or obesity examined the effects of longer-term mixed nut consumption on lipoprotein particle size, number, and lipid distribution.

METHODS

Twenty-eight participants (aged 65 ± 3 years; BMI 27.9 ± 2.3 kg/m2) completed two 16-week periods (control [no nuts] vs. mixed nuts (60 g/day: 15 g of walnuts, pistachios, cashews, and hazelnuts), separated by an 8-week washout. Plasma lipoprotein particle numbers, sizes, and lipid distributions across subclasses were analyzed using high-throughput nuclear magnetic resonance (NMR) spectroscopy.

RESULTS

Mixed nut consumption significantly reduced Apolipoprotein B (ApoB) concentrations (-0.07 g/L; p = 0.009), total cholesterol (-0.27 mmol/L; p = 0.047), non-HDL cholesterol (-0.28 mmol/L; p = 0.022), and total triacylglycerol (TAG) (-0.27 mmol/L; p = 0.008). Total very large-density lipoprotein (VLDL) particle numbers decreased by 24 nmol/L (p < 0.001), with reductions observed across all VLDL subclasses. Total LDL particle numbers (p = 0.044), specifically intermediate-density lipoprotein (IDL) (p = 0.002) and large LDL particles (p = 0.015), were also reduced, while HDL particle numbers and sizes were unaffected. The mixed nut intervention significantly reduced cholesterol concentrations across all VLDL subclasses and IDL (all p < 0.01), with no changes in LDL or HDL subclasses. TAG concentrations showed reductions across all lipoprotein subclasses (all p < 0.05).

CONCLUSIONS

Longer-term mixed nut consumption may lower CVD risk in older adults and favorable shifts in apoB-containing lipoprotein subclasses towards a less atherogenic profile.