Avocado consumption and risk factors for heart disease: a systematic review and meta-analysis

Nutrients in avocados are associated with cardiovascular benefits. The aim of this study was to determine the effect of avocado intake on cardiovascular disease (CVD) risk with the use of a systematic review and meta-analysis. MEDLINE, Cochrane Central, and Commonwealth Agricultural Bureau abstracts were searched from 1946 through September 2017 for publications on avocado intake and CVD risk. All designs except for cross-sectional studies that evaluated avocado intake were included. Two investigators independently screened citations and extracted data. Random-effects models meta-analysis was used when >= 3 studies reported the same outcome. Of 18 eligible studies (481 subjects), 7 studies compared avocado intake with no intake, 3 studies compared avocado plus monounsaturated fat intake with a control, and 8 studies reported data for qualitative synthesis. In 7 studies, avocado intake significantly increased HDL cholesterol (summary net change: 2.84 mg/dL; 95% CI: 0.18, 5.49 mg/dL), with significant heterogeneity. This remained consistent in sensitivity and subgroup analyses. There was no significant difference between avocado intake and the control for the outcomes of serum total cholesterol (TC), LDL cholesterol, triglycerides (TGs), ratios of TC to HDL cholesterol and LDL cholesterol to HDL cholesterol, and body weight. In qualitative synthesis, there was no significant difference between groups for blood glucose (2 studies), homeostasis model assessment (1 of 2 studies), oxidized LDL (2 studies), high-sensitivity C-reactive protein (2 studies), or apolipoprotein B (2 studies) or, in 1 study each, for body mass index, systolic and diastolic blood pressure, arterial compliance, fibrinogen, interleukin 6, tumor necrosis factor alpha, and serum nitric oxide. No studies reported incident clinical outcomes of CVD, including myocardial infarction, stroke, and other clinical endpoints. Avocado intake resulted in no difference in serum TC, LDL-cholesterol, and TG concentrations, but it did increase serum HDL-cholesterol concentrations, with significant heterogeneity. The association between avocado intake and CVD risk should be confirmed by well-conducted prospective observational studies or long-term trials.