Effects of Walnut Consumption on Endothelial Function in Type 2 Diabetic Subjects: A randomized controlled crossover trial

• Published in: Diabetes care Vol. 33; no. 2; pp. 227 - 232
• Main Authors: YINGYING MA, YANCHOU NJIKE, Valentine, MILLET, John, DUTTA, Suparna, DOUGHTY, Kim, TREU, Judith A, KATZ, David L
• Format: Journal Article
• Language: English
• Published: Alexandria, VA American Diabetes Association 01.02.2010
• Subjects: Adult; Aged; Antilipemic agents; Biological and medical sciences; biomarkers; blood; blood glucose; blood lipids; blood serum; Brachial Artery; Brachial Artery - physiopathology; Cross-Over Studies; Diabetes; Diabetes Mellitus, Type 2; Diabetes Mellitus, Type 2 - physiopathology; Diabetes. Impaired glucose tolerance; diet; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Endothelium; Endothelium, Vascular; Endothelium, Vascular - physiology; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Fasting; Female; foot-and-mouth disease; Functional Laterality; glucose; Glycated Hemoglobin; Glycated Hemoglobin A - metabolism; Humans; Hyperemia; Hyperemia - physiopathology; Insulin; Insulin - blood; insulin resistance; Juglans; Lipids; Lipids - blood; low density lipoprotein cholesterol; Male; Medical sciences; men; Metabolic diseases; metabolism; Middle Aged; Miscellaneous; noninsulin-dependent diabetes mellitus; Nut industry; Original Research; physiology; physiopathology; Public health. Hygiene; Public health. Hygiene-occupational medicine; risk; Single-Blind Method; Type 2 diabetes; Vasodilation; walnuts; women; Endocrinopathy; Consumption; Type 2 diabetes; Human; Endothelial cell; Nutrition; Metabolic diseases; Endothelium; Randomization; Walnut; Randomised controlled trial; Clinical trial; Endocrinology
• ISSN: 0149-5992; 1935-5548; 1935-5548
• DOI: 10.2337/dc09-1156

To determine the effects of daily walnut consumption on endothelial function, cardiovascular biomarkers, and anthropometric measures in type 2 diabetic individuals. This study was a randomized, controlled, single-blind, crossover trial. Twenty-four participants with type 2 diabetes (mean age 58 years; 14 women and 10 men) were randomly assigned to one of the two possible sequence permutations to receive an ad libitum diet enriched with 56 g (366 kcal) walnuts/day and an ad libitum diet without walnuts for 8 weeks. Subjects underwent endothelial function testing (measured as flow-mediated dilatation [FMD]) and assessment of cardiovascular biomarkers before and after each 8-week treatment phase. The primary outcome measure was the change in FMD after 8 weeks. Secondary outcome measures included changes in plasma lipids, A1C, fasting glucose, insulin sensitivity, and anthropometric measures. Endothelial function significantly improved after consumption of a walnut-enriched ad libitum diet compared with that after consumption of an ad libitum diet without walnuts (2.2 +/- 1.7 vs. 1.2 +/- 1.6%; P = 0.04). The walnut-enriched diet increased fasting serum glucose and lowered serum total cholesterol and LDL cholesterol from baseline (10.0 +/- 20.5 mg/dl, P = 0.04; -9.7 +/- 14.5 mg/dl, P < 0.01; and -7.7 +/- 10 mg/dl, P < 0.01, respectively), although these changes were not significant compared with those for an ad libitum diet without walnuts. There were no significant changes in anthropometric measures, plasma A1C, and insulin sensitivity. A walnut-enriched ad libitum diet improves endothelium-dependent vasodilatation in type 2 diabetic individuals, suggesting a potential reduction in overall cardiac risk.