N-3 index is associated with cardiometabolic risk factors but is not improved by walnut intake in free-living elderly: a single-blind, randomised controlled trial. Issue 4 (28th February 2023)

• Record Type: Journal Article
• Authors: Jehi, Tony; Sabaté, Joan; Bitok, Edward; Sala-Vila, Aleix; Ros, Emilio; Cofan, Montse; Oda, Keiji; Rajaram, Sujatha
• Is Part Of: British journal of nutrition. Volume 129:Issue 4(2023)
• Page Start: 670
• Page End: 677
• Publication Date: 2023-02-28
• Subjects: Cardiometabolic disease -- α-Linolenic acid -- n-3 Index -- Walnuts; Nutrition -- Periodicals; 572.4
• DOI: 10.1017/S0007114522001751
• Languages: English
• ISSNs: 0007-1145

Abstract

Abstract: n -3 index, the erythrocyte proportion of the EPA + DHA fatty acids is a clinical marker of age-related disease risk. It is unclear whether regular intake of α -linolenic acid (ALA), a plant-derived n -3 polyunsaturated fatty acid, raises n -3 index in older adults. Of the 356 participants at the Loma Linda, CA centre from the original study, a randomly selected subset ( n 192) was included for this secondary analysis (mostly Caucasian women, mean age 69 years). Participants were assigned to either the walnut (15 % of daily energy from walnuts) or the control group (usual diet, no walnuts) for 2 years. Erythrocyte fatty acids were determined at baseline and 1-year following intervention. No differences were observed for erythrocyte EPA, but erythrocyte DHA decreased albeit modestly in the walnut group (–0·125 %) and slightly improved in the control group (0·17 %). The change in n -3 index between the walnut and control groups was significantly different only among fish consumers (those who ate fish ≥ once/month). Longitudinal analyses combining both groups showed significant inverse association between the 1-year changes of the n -3 index and fasting plasma TAG ( ß = −10), total cholesterol ( ß = −5·59) and plasma glucose ( ß = −0·27). Consuming ALA-rich walnuts failed to improve n -3 index in elders. A direct source of EPA/DHA may be needed to achieve desirable n -3 index, as it is inversely associated with cardiometabolic risk. Nevertheless, incorporating walnuts as part of heart healthy diets is still encouraged.