Avocado Consumption and Cardiometabolic Health: A Systematic Review and Meta-Analysis

Abstract

Background: Avocados are a rich source of unsaturated fats and bioactives, however, their role in altering cardiometabolic risk factors is unclear.

Objective: The aim was to review the effects of consuming diets containing avocado compared with control diets containing no or low amounts of avocado on cardiometabolic risk factors in adults who were healthy, had clinical cardiovascular disease, or were at increased risk of cardiovascular disease.

Methods: Five electronic databases were searched (PubMed, Web of Science, Scopus, ProQuest, and a Clinical Trials Registry) along with Google Scholar to identify studies published between January 1990 and November 10, 2021. Randomized controlled trials ≥3 weeks and prospective cohort studies were included. Ten studies-9 randomized controlled trials (n = 503 participants) and 1 prospective observational study (n = 55,407)-met the inclusion criteria. Outcomes assessed by means of meta-analysis were low-density lipoprotein cholesterol (LDL-C) (primary), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and triglycerides. Outcomes assessed by narrative review were TC to HDL-C ratio, non-HDL-C, apolipoprotein B, blood pressure, body weight, body mass index (calculated as kg/m²), waist circumference, waist-to-hip ratio, body composition, and blood glucose and insulin concentrations. Risk of bias was assessed using the Cochrane Risk of Bias tool, version 2.0 and Newcastle-Ottawa Scale; quality of evidence was examined using the Grading of Recommendations, Assessment, Development and Evaluation method. Random-effects models meta-analyses were performed when there were ≥3 studies of the same design (ie, randomized controlled trial) and reporting the same outcome. Statistical heterogeneity was assessed by calculating χ² and I² statistics and publication bias was assessed by funnel plots.

Results: Overall, there was a small, significant reduction in TC (-5.08 mg/dL [to convert to mmol/L, divide by 38.67]; 95% CI -9.29 to -0.87 mg/dL; P = .02) in avocado vs the control groups and no significant difference in LDL-C, HDL-C, or triglycerides. Subgroup analysis demonstrated significant reductions in LDL-C (-9.4 mg/dL [to convert to mmol/L, divide by 38.67]; 95% CI -10.84 to -7.95 mg/dL; P < .00001) and TC (-7.54 mg/dL; 95% CI -9.40 to -5.68 mg/dL; P < .00001) in avocado vs control groups in hypercholesterolemic populations, and no differences were seen in normocholesterolemic populations. However, the certainty in the findings was graded as low to very low. Body weight and composition were not negatively affected by avocado consumption.

Conclusions: Avocado consumption may reduce TC and LDL-C in people with hypercholesterolemia. Avocado consumption does not negatively impact body weight. Larger, well-conducted studies are needed to have greater confidence in the role of avocado consumption on cardiovascular disease risk factors.

Keywords: Avocado; Body composition; Cardiometabolic health; Cardiovascular disease; Cholesterol.