Deirdre K Banel1, Frank B Hu. 1. Department of Nutrition and Epidemiology, Harvard School of Public Health, Harvard University, Cambridge, MA, USA. dbanel@hsph.harvard.edu
Abstract
BACKGROUND: Consumption of nuts has been associated with a decreased risk of cardiovascular disease events and death. Walnuts in particular have a unique profile: they are rich in polyunsaturated fatty acids, which may improve blood lipids and other cardiovascular disease risk factors. OBJECTIVES: We aimed to conduct a literature review and a meta-analysis to combine the results from several trials and to estimate the effect of walnuts on blood lipids. DESIGN: Literature databases were searched for published trials that compared a specifically walnut-enhanced diet with a control diet. We conducted a random-effects meta-analysis of weighted mean differences (WMDs) of lipid outcomes. RESULTS: Thirteen studies representing 365 participants were included in the analysis. Diets lasted 4-24 wk with walnuts providing 10-24% of total calories. When compared with control diets, diets supplemented with walnuts resulted in a significantly greater decrease in total cholesterol and in LDL-cholesterol concentrations (total cholesterol: WMD = -10.3 mg/dL, P < 0.001; LDL cholesterol: WMD = -9.2 mg/dL, P < 0.001). HDL cholesterol and triglycerides were not significantly affected by walnut diets more than with control diets (HDL cholesterol: WMD = -0.2, P = 0.8; triglycerides: WMD = -3.9, P = 0.3). Other results reported in the trials indicated that walnuts provided significant benefits for certain antioxidant capacity and inflammatory markers and had no adverse effects on body weight [body mass index (kg/m(2)): WMD = -0.4, P = 0.5; weight (kg): WMD = -0.05, P = 0.97]. CONCLUSIONS: Overall, high-walnut-enriched diets significantly decreased total and LDL cholesterol for the duration of the short-term trials. Larger and longer-term trials are needed to address the effects of walnut consumption on cardiovascular risk and body weight.
BACKGROUND: Consumption of nuts has been associated with a decreased risk of cardiovascular disease events and death. Walnuts in particular have a unique profile: they are rich in polyunsaturated fatty acids, which may improve blood lipids and other cardiovascular disease risk factors. OBJECTIVES: We aimed to conduct a literature review and a meta-analysis to combine the results from several trials and to estimate the effect of walnuts on blood lipids. DESIGN: Literature databases were searched for published trials that compared a specifically walnut-enhanced diet with a control diet. We conducted a random-effects meta-analysis of weighted mean differences (WMDs) of lipid outcomes. RESULTS: Thirteen studies representing 365 participants were included in the analysis. Diets lasted 4-24 wk with walnuts providing 10-24% of total calories. When compared with control diets, diets supplemented with walnuts resulted in a significantly greater decrease in total cholesterol and in LDL-cholesterol concentrations (total cholesterol: WMD = -10.3 mg/dL, P < 0.001; LDL cholesterol: WMD = -9.2 mg/dL, P < 0.001). HDL cholesterol and triglycerides were not significantly affected by walnut diets more than with control diets (HDL cholesterol: WMD = -0.2, P = 0.8; triglycerides: WMD = -3.9, P = 0.3). Other results reported in the trials indicated that walnuts provided significant benefits for certain antioxidant capacity and inflammatory markers and had no adverse effects on body weight [body mass index (kg/m(2)): WMD = -0.4, P = 0.5; weight (kg): WMD = -0.05, P = 0.97]. CONCLUSIONS: Overall, high-walnut-enriched diets significantly decreased total and LDL cholesterol for the duration of the short-term trials. Larger and longer-term trials are needed to address the effects of walnut consumption on cardiovascular risk and body weight.
Authors: John M Morgan; Kirsten Horton; Dana Reese; Christina Carey; Kalen Walker; David M Capuzzi Journal: Int J Vitam Nutr Res Date: 2002-10 Impact factor: 1.784
Authors: Kim J Spaccarotella; Penny M Kris-Etherton; William L Stone; Deborah M Bagshaw; Valerie K Fishell; Sheila G West; Frank R Lawrence; Terryl J Hartman Journal: Nutr J Date: 2008-05-02 Impact factor: 3.271
Authors: Sheila G West; Sarah K Gebauer; Colin D Kay; Deborah M Bagshaw; David M Savastano; Christopher Diefenbach; Penny M Kris-Etherton Journal: Hypertension Date: 2012-06-04 Impact factor: 10.190
Authors: Konstantinos N Aronis; Maria T Vamvini; John P Chamberland; Laura L Sweeney; Aoife M Brennan; Faidon Magkos; Christos S Mantzoros Journal: Metabolism Date: 2011-11-09 Impact factor: 8.694
Authors: Liana C Del Gobbo; Michael C Falk; Robin Feldman; Kara Lewis; Dariush Mozaffarian Journal: Am J Clin Nutr Date: 2015-11-11 Impact factor: 7.045
Authors: Siew Ling Tey; Terryn Robinson; Andrew R Gray; Alexandra W Chisholm; Rachel Clare Brown Journal: Eur J Nutr Date: 2016-01-08 Impact factor: 5.614
Authors: Cheryl L Rock; Shirley W Flatt; Bilge Pakiz; Elizabeth L Quintana; Dennis D Heath; Brinda K Rana; Loki Natarajan Journal: Metabolism Date: 2016-07-25 Impact factor: 8.694
Authors: Sheila G West; Andrea Likos Krick; Laura Cousino Klein; Guixiang Zhao; Todd F Wojtowicz; Matthew McGuiness; Deborah M Bagshaw; Paul Wagner; Rachel M Ceballos; Bruce J Holub; Penny M Kris-Etherton Journal: J Am Coll Nutr Date: 2010-12 Impact factor: 3.169
Authors: Sonia S Anand; Corinna Hawkes; Russell J de Souza; Andrew Mente; Mahshid Dehghan; Rachel Nugent; Michael A Zulyniak; Tony Weis; Adam M Bernstein; Ronald M Krauss; Daan Kromhout; David J A Jenkins; Vasanti Malik; Miguel A Martinez-Gonzalez; Dariush Mozaffarian; Salim Yusuf; Walter C Willett; Barry M Popkin Journal: J Am Coll Cardiol Date: 2015-10-06 Impact factor: 24.094