Five RCTs (n=142) were included in the review. Four of the trials had a crossover design. One RCT was double-blinded, one was single-blinded and the others were open-label. All trials reported follow-up at four weeks.
Total cholesterol in almond groups was lowered by a statistically significantly greater degree than in the control groups (WMD -0.18, 95% CI -0.34 to -0.02, p=0.03; five RCTs, nine comparisons). There was no statistically significant difference between groups for outcomes of LDL cholesterol, HDL cholesterol, triglycerides or LDL:HDL ratio. There was no evidence of significant statistical heterogeneity between the studies in any analysis (I2=0% in all cases).
Subgroup and sensitivity analyses did not materially alter results of analyses except for statistically significant treatment effects for both LDL and HDL cholesterol in hyperlipidaemia patients and LDL cholesterol in non-diabetic individuals. There was evidence of an effect on HDL cholesterol in blinded studies.
There was no evidence of publication bias. The strength of evidence was considered to be moderate for total and LDL cholesterol and low for other outcomes.