Walnut-enriched diet reduces fasting non-HDL-cholesterol and apolipoprotein B in healthy Caucasian subjects: a randomized controlled cross-over clinical trial

Metabolism. 2014 Mar;63(3):382-91. doi: 10.1016/j.metabol.2013.11.005. Epub 2013 Nov 12.


Background: Walnut consumption is associated with reduced risk of coronary heart disease (CHD).

Objective: We assessed the effect of walnuts on lipid and glucose metabolism, adipokines, inflammation and endothelial function in healthy Caucasian men and postmenopausal women ≥50years old.

Design: Forty subjects (mean±SEM: age 60±1years, BMI 24.9±0.6kg/m(2); 30 females) were included in a controlled, cross-over study and randomized to receive first a walnut-enriched (43g/d) and then a Western-type (control) diet or vice-versa, with each lasting 8weeks and separated by a 2-week wash-out. At the beginning and end of each diet phase, measurements of fasting values, a mixed meal test and an assessment of postprandial endothelial function (determination of microcirculation by peripheral artery tonometry) were conducted. Area under the curve (AUC), incremental AUC (iAUC) and treatment×time interaction (shape of the curve) were evaluated for postprandial triglycerides, VLDL-triglycerides, chylomicron-triglycerides, glucose and insulin.

Results: Compared with the control diet, the walnut diet significantly reduced non-HDL-cholesterol (walnut vs. control: -10±3 vs. -3±2mg/dL; p=0.025) and apolipoprotein-B (-5.0±1.3 vs. -0.2±1.1mg/dL; p=0.009) after adjusting for age, gender, BMI and diet sequence. Total cholesterol showed a trend toward reduction (p=0.073). Fasting VLDL-cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides and glucose, insulin, HOMA-IR, and HbA1c did not change significantly. Similarly, fasting adipokines, C-reactive protein, biomarkers of endothelial dysfunction, postprandial lipid and glucose metabolism and endothelial function were unaffected.

Conclusion: Daily consumption of 43g of walnuts for 8weeks significantly reduced non-HDL-cholesterol and apolipoprotein-B, which may explain in part the epidemiological observation that regular walnut consumption decreases CHD risk.

Keywords: Endothelial function; Glucose; Lipids; Nuts; Peripheral artery tonometry.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipokines / blood
  • Apolipoproteins B / blood*
  • C-Reactive Protein / metabolism
  • Cholesterol, HDL / blood*
  • Cholesterol, LDL / blood*
  • Cholesterol, VLDL / blood*
  • Chylomicrons / metabolism
  • Cross-Over Studies
  • Diet / methods
  • Endothelium / metabolism
  • Fasting
  • Female
  • Glucose / metabolism
  • Glycated Hemoglobin A / metabolism
  • Humans
  • Inflammation / blood
  • Inflammation / metabolism
  • Insulin / blood
  • Juglans
  • Lipid Metabolism / physiology*
  • Lipoproteins, VLDL / blood
  • Male
  • Middle Aged
  • Postprandial Period / physiology
  • Prospective Studies
  • Triglycerides / blood*
  • Whites


  • Adipokines
  • Apolipoproteins B
  • Cholesterol, HDL
  • Cholesterol, LDL
  • Cholesterol, VLDL
  • Chylomicrons
  • Glycated Hemoglobin A
  • Insulin
  • Lipoproteins, VLDL
  • Triglycerides
  • hemoglobin A1c protein, human
  • very low density lipoprotein triglyceride
  • C-Reactive Protein
  • Glucose