The consumption of nuts was reported to be associated with risk of hypertension and type 2 diabetes mellitus (T2DM), but the results were inconclusive.
The aim of this study was to systematically examine longitudinal studies investigating nut intake in relation to risk of hypertension and T2DM.
A systematic search of the PubMed and EMBASE databases to 31 March 2013 was performed. Reference lists of retrieved articles were also screened. Summary relative risks (SRRs) and 95% confidence interval(CIs) were calculated using a random-effects model. Q and I2 statistics were used to examine between-study heterogeneity.
A total of nine prospective cohort studies (three for hypertension and six for T2DM) were identified. Using random effects models, we found that based on the highest vs lowest analysis, nut consumption were inversely asso- ciated with risk of hypertension (SRR 1⁄4 0.84, 95% CI: 0.76–0.93, pheterogeneity 1⁄4 0.831, I2 1⁄4 0%). Dose-response analyses indicated that nut consumption at more than two servings/wk, but not ne serving/wk, had a preventative role in the hypertension. In addition, nut consumption was not associated with risk of T2DM (SRRs 1⁄4 0.98, 95% CI: 0.84–1.15; pheterogeneity 1⁄4 0.008, I2 1⁄4 67.7%) on the basis of the highest vs lowest analysis. This null association was also shown in the dose-response analysis.
In our meta-analysis, nut consumption is found to be inversely associated with hypertension risk but is not associated with the risk of T2DM.