A study published in Metabolism indicates a diet with walnuts may reduce cardiovascular disease risk by lowering non-HDL cholesterol and apolipoprotein B (ApoB)—two predictors of cardiovascular disease.
Researchers at University of Munich Medical Center, Germany, investigated the effects of daily walnut consumption (43 g/1.5 oz) on blood lipid levels that predict cardiovascular disease risk, and found non-HDL cholesterol and ApoB levels were significantly reduced on the walnut-enriched diet by over 6% and 5%, respectively.
Forty subjects were included in a controlled, cross-over study and randomized to receive first a walnut-enriched (43 g/day) and then a Western-type (control) diet or vice-versa, with each lasting eight weeks and separated by a two-week wash-out period. 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.
Compared with the control diet, the walnut diet significantly reduced non-HDL-cholesterol and apolipoprotein-B after adjusting for age, gender, BMI, and diet sequence. Total cholesterol showed a trend toward reduction. 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.
The researchers concluded that "daily consumption of 43 g of walnuts for eight weeks significantly reduced non-HDL-cholesterol and apolipoprotein-B, which may explain in part the epidemiological observation that regular walnut consumption decreases CHD risk."