A Walnut-Enriched Diet Reduces Lipids in Healthy Caucasian Subjects, Independent of Recommended Macronutrient Replacement and Time Point of Consumption: a Prospective, Randomized, Controlled Trial.

Charlotte Bamberger,Elisa Waldmann,Andreas Rossmeier,Katharina Lechner,Klaus G Parhofer,Julia Altenhofer,Renée G Stark,Kerstin Henze,Liya Wu

doi:10.3390/nu9101097

Charlotte Bamberger, Elisa Waldmann + Show 7 more

Open Access

https://doi.org/10.3390/nu9101097

Copy DOI

Abstract

Studies indicate a positive association between walnut intake and improvements in plasma lipids. We evaluated the effect of an isocaloric replacement of macronutrients with walnuts and the time point of consumption on plasma lipids. We included 194 healthy subjects (134 females, age 63 ± 7 years, BMI 25.1 ± 4.0 kg/m2) in a randomized, controlled, prospective, cross-over study. Following a nut-free run-in period, subjects were randomized to two diet phases (8 weeks each). Ninety-six subjects first followed a walnut-enriched diet (43 g walnuts/day) and then switched to a nut-free diet. Ninety-eight subjects followed the diets in reverse order. Subjects were also randomized to either reduce carbohydrates (n = 62), fat (n = 65), or both (n = 67) during the walnut diet, and instructed to consume walnuts either as a meal or as a snack. The walnut diet resulted in a significant reduction in fasting cholesterol (walnut vs. control: −8.5 ± 37.2 vs. −1.1 ± 35.4 mg/dL; p = 0.002), non-HDL cholesterol (−10.3 ± 35.5 vs. −1.4 ± 33.1 mg/dL; p ≤ 0.001), LDL-cholesterol (−7.4 ± 32.4 vs. −1.7 ± 29.7 mg/dL; p = 0.029), triglycerides (−5.0 ± 47.5 vs. 3.7 ± 48.5 mg/dL; p = 0.015) and apoB (−6.7 ± 22.4 vs. −0.5 ± 37.7 mg/dL; p ≤ 0.001), while HDL-cholesterol and lipoprotein (a) did not change significantly. Neither macronutrient replacement nor time point of consumption significantly affected the effect of walnuts on lipids. Thus, 43 g walnuts/day improved the lipid profile independent of the recommended macronutrient replacement and the time point of consumption.

Highlights

A number of factors are causally linked to cardiovascular disease (CVD), alterations in lipid metabolism, and an elevated concentration of apolipoprotein B-containing lipoproteins are considered major risk factors [1]
It has been shown that walnut consumption can affect clinically relevant endpoints, and that this may be mediated through effects on oxidative stress, inflammation, and lipids [6,7,8]
We investigated the effect of daily consumption of 43 g (1.5 oz) walnuts within a Western-type diet over eight weeks in healthy Caucasian men and postmenopausal women on lipid and glucose metabolism, adipokines, and endothelial function [18]

Summary

Introduction

A number of factors are causally linked to cardiovascular disease (CVD), alterations in lipid metabolism, and an elevated concentration of apolipoprotein B (apoB)-containing lipoproteins are considered major risk factors [1]. There is strong epidemiologic and clinical evidence that diets rich in omega-3 (n-3) fatty acids are protective and may reduce cardiovascular and overall mortality [3,4,5]. In this context, nuts—especially walnuts—play a key role due to their unique fatty acid composition with high content of unsaturated fatty acids, polyunsaturated fatty acids (PUFA). Dietary controls have been variable, the overall results of these clinical trials have consistently shown a cholesterol-lowering effect of regular nut consumption [17]

Objectives

Methods

Conclusion