Effects of nut and seed consumption on markers of glucose metabolism in adults with prediabetes: a systematic review of randomised controlled trials

Abstract

The primary aim was to investigate the effects of nut and seed consumption on markers of glucose metabolism in adults with prediabetes. Studies with a randomised controlled trial (RCT) design, comparing the effects of a diet containing nuts or seeds against a diet without nuts or seeds in adults with prediabetes, were considered eligible. Primary outcome measures included fasting plasma glucose (FPG), 2-h plasma glucose during oral glucose tolerance test and glycated Hb (HbA1c) concentrations. Studies were identified by searching PubMed and Scopus electronic databases and by checking full texts and reference lists of relevant records. Risk of bias was assessed using the Cochrane Collaboration’s tool. We included five RCT involving 371 adults with prediabetes or at risk of diabetes; three RCT investigated the effects of whole nut consumption and two the effects of ground flaxseed consumption. Consumption of 57 g/d pistachios or mean intake of 60 g/d almonds for 4 months improved FPG and fasting plasma insulin (FPI) concentrations, insulin resistance, cellular glucose uptake in lymphocytes and β-cell function. Consumption of 56 g/d walnuts for 6 months was not found to affect FPG or HbA1c concentrations. Consumption of 13 g/d flaxseed for 3 months improved FPG and FPI concentrations and insulin resistance. In a second study, however, flaxseed consumption was not found to affect markers of glucose metabolism. The risk of bias was generally low, thus the reported results could be reliable. Further investigation of nut and seed consumption effects in the field of prediabetes is warranted.

A Comprehensive Review of Almond Clinical Trials on Weight Measures, Metabolic Health Biomarkers and Outcomes, and the Gut Microbiota

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The effect of almond intake on glycemic control: A systematic review and dose–response meta‐analysis of randomized controlled trials

“…Previous studies investigated the effect of different nut consumption on several cardiovascular risk factors and also glycemic control; but those studies evaluated whole nuts and not specifically on definite nuts Ntzouvani, Antonopoulou, & Nomikos, 2019;Viguiliouk et al, 2014). As described, recent meta-analyses examining tree nuts, including almonds on glycemic control in adults.…”

The effect of daily peanut consumption on cognitive function and indicators of mental health among healthy young women

“…Habitual nut intake is associated with numerous health benefits such as reduced risk of cardiovascular disease, type II diabetes, and metabolic syndrome [1][2][3]. Nuts (including peanuts and tree nuts) contain an array of beneficial antioxidants, phytochemicals, and healthy fats, all of which may contribute to their beneficial association with health [4].…”

“…Within group differences. P-values calculated from paired sample t-tests 2. Between group differences in baseline scores.…”