The effects of foods on LDL cholesterol levels: A systematic review of the accumulated evidence from systematic reviews and meta-analyses of randomized controlled trials

Abstract Aims To systematically evaluate the evidence regarding the effects of foods on LDL cholesterol levels and to compare the findings with current guidelines. Data Synthesis From inception through June 2019, we searched PubMed, Cochrane Database of Systematic Reviews, and Cochrane Central Register of Controlled Trials for guidelines, systematic reviews, and RCTs (for coffee intake only) of at least 13 days duration. Additionally, we searched Trip database for guidelines from 2009 through Oct 2019. Language was restricted to English. The strength of evidence was evaluated using The Grading of Recommendations Assessment, Development, and Evaluation (GRADE). A total of 37 guidelines, 108 systematic reviews, and 20 RCTs were included. With high evidence, foods high in unsaturated and low in saturated and trans fatty acids (e.g. rapeseed/canola oil), with added plant sterols/stanols, and high in soluble fibre (e.g. oats, barley, and psyllium) caused at least moderate (i.e. 0.20–0.40 mmol/L) reductions in LDL cholesterol. Unfiltered coffee caused a moderate to large increase. Soy protein, tomatoes, flaxseeds, and almonds caused small reductions. With moderate evidence, avocados and turmeric caused moderate to large reductions. Pulses, hazelnuts, walnuts, high-fibre/wholegrain foods, and green tea caused small to moderate reductions, whereas sugar caused a small increase. Other identified foods were either neutral or had low or very low evidence regarding their effects. Conclusions Several foods distinctly modify LDL cholesterol levels. The results may aid future guidelines and dietary advice for hypercholesterolemia.