Nut consumption and type 2 diabetes risk: a systematic review and meta-analysis of observational studies

Abstract

Background Previous meta-analyses, with some methodological controversies, have assessed the relation between nut consumption and type 2 diabetes (T2D) risk and pointed to contradictory results, making desirable the performance of an updated meta-analysis. Objectives We aimed to systematically review and meta-analyze all the published studies investigating the relations of total nuts and different types of nuts—i.e., walnuts, peanuts, peanut butter, and total tree nuts—with the prevalence and incidence of T2D. Methods A systematic search was conducted in the PubMed and Cochrane databases through 12 August, 2020. The inverse variance method with fixed-effect models was used to pool data across studies, expressed as risk ratios (RRs) or ORs and 95% CIs for prospective cohort and cross-sectional studies, respectively. The Cochran Q test and I2 statistics were used to test and quantify heterogeneity, respectively. Dose-response meta-analysis was also conducted. Results Eight studies (5 prospective and 3 cross-sectional) were included in the quantitative synthesis. Meta-analyses of cross-sectional studies and prospective cohort studies, comparing the highest with the lowest categories, revealed a nonsignificant association between total nut consumption and T2D. Meta-analyses of prospective cohort studies showed an inverse association between peanut butter consumption and T2D incidence (RR: 0.87; 95% CI: 0.77, 0.98; I2 = 50.6%; Pheterogeneity = 0.16), whereas no association was observed between peanuts or tree nuts and T2D. There was no evidence of a linear dose-response or nonlinear dose-response gradient for total nut and peanut consumption in prospective cohort studies. The certainty of the evidence using NutriGrade was very low for all the exposures. Conclusions Current results do not demonstrate an association of total nut, peanut, or tree nut consumption with T2D. Peanut butter consumption may be inversely associated with this disease. This review protocol was registered at www.crd.york.ac.uk/prospero/ as CRD42020149756.

Nutritional Quality of Plant-Based Cheese Available in Spanish Supermarkets: How Do They Compare to Dairy Cheese?

“…In the case of cashew nut-based products, around 50% of their weight were cashews, being the major ingredient, followed by water and lemon juice. The health benefits of whole nuts consumption is well-known [ 33 , 34 ], and it has been reported that other nut-based processed products, such as peanut butter without added sugars, could provide some health benefits, reducing the risk of type 2 diabetes incidence [ 35 ]. In the case of tofu-based products, 98.5% of the products’ weight is soy milk.…”

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

“…It is estimated that 20% of these T2 diabetes healthcare costs are related to the addition to the diet of high glycemic index (GI) and glycemic load (GL) foods, which are reduced with almond intake, an essentially zero gI and gL food [1]. Although Becerra-Tomas et al [121], in a systematic review and meta-analysis of 8 observational studies, found no association between total nuts, tree nuts, or peanuts and risk of T2 diabetes. Jenkins et al [112], in an RCT, showed that nuts as a replacement for carbohydrates improves glycemic control, including lowering hbA1c, and reduces CVD risk by lowering the number of small LDL particles and levels of TC, LDL-C, non-HDL-C, and Apo-B in individuals with T2 diabetes.…”

Nuts: Natural Pleiotropic Nutraceuticals

“…The effects of nut consumption on risk of type-2 diabetes mellitus (T2D) in epidemiological studies have mostly been inconclusive and controversial [ 35 , 37 ]. A recent meta-analysis of nine studies (six prospective, three cross-sectional) published between 2002 and 2018 reported no association between extremes of consumption of total nuts, tree nuts or peanuts and the risk of T2D [ 38 ]. Walnuts, however, appeared to behave differently, as one large prospective study from the NHS and HPFS cohorts included in the meta-analysis found that walnut consumption related inversely to T2D risk (RR = 0.76; 95% CI, 0.62, 0.94) [ 39 ], while another large cross-sectional study found an even more beneficial effect of walnuts on T2D (RR = 0.47; 95% CI, 0.31, 0.71) [ 40 ].…”

“…Yet, only the results of one of the two analyzed studies favored peanut butter for T2D risk. Notably, risk estimates for total nuts changed substantially from nonsignificant to significant for lower T2D risk when time-updated measurement of body mass index (BMI) obtained during follow-up was excluded from the model (RR = 0.85; 95% CI, 0.75, 0.95), which supports body weight changes as a mediator of the reduction in T2D risk [ 38 ]. In fact, there is increasing evidence from prospective studies that regular nut consumption is associated with less long-term weight gain and a lower risk of obesity, while short-term RCTs confirm the lack of fattening effect of nuts [ 35 ].…”