Does Medication Status Impact the Effectiveness of Nuts in Altering Blood Pressure and Lipids? A Systematic Review and Meta-Analysis.

Context: Nut consumption is attributed to improvements in risk factors for cardiovascular disease (CVD), including high blood pressure (BP) and dyslipidemia. However, it is unclear whether these effects are altered with concurrent treatment with BP and lipid-lowering medication.

Objective: We sought to investigate the effects of the consumption of whole tree nuts and peanuts (collectively termed nuts) on BP and lipids, and whether BP and lipid-lowering medication use alters these effects.

Data Sources: The MEDLINE, EMBASE, Scopus, and Web of Science databases were systematically searched through June 21, 2023, for randomized controlled trials (RCTs) assessing the effects of nut consumption on BP and/or lipids.

Data Extraction: Random effects meta-analyses (mean difference, 95% confidence interval [CI]) were conducted, with subgroup analyses based on reported participant use of BP or lipid-lowering medication, including medicated, unmedicated, unreported (ie, use not specified), and mixed (ie, included combined data from medicated and unmedicated participants). A total of 115 studies were included in the review, of which 109 were meta-analysed.

Data Analysis: Nut consumption significantly reduced triglycerides (TG), total cholesterol, low-density lipoprotein cholesterol, very-low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol, and apolipoprotein B, with no effect on high-density lipoprotein cholesterol or blood pressure. Few studies were conducted in medicated participants only (n = 1 for lipid outcomes only), and for the studies including both medicated and unmedicated participants (ie, mixed), outcomes by medication use were not reported. Significant differences in TG and apolipoprotein B were observed between medication use groups, with nut consumption resulting in the largest reductions in unmedicated participants. Strong heterogeneity was observed with no evidence of publication bias.

Conclusions: Lipid-lowering, but not BP-lowering benefits of nut consumption were observed; however, few studies reported the effect based on participants' medication status. Future studies are required to determine if there are additional benefits of including nuts in the diet of medicated patients with cardiovascular disease.

Systematic Review Registration: PROSPERO registration code CRD42022296849.