Impact of Diet on Plasma Lipids in Individuals with Heterozygous Familial Hypercholesterolemia: A Systematic Review of Randomized Controlled Nutritional Studies

• Published in: Nutrients 2021-01, Vol.13 (1), p.235
• Main Authors: Roy, Gabrielle, Boucher, Anykim, Couture, Patrick, Drouin-Chartier, Jean-Philippe
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Atherosclerosis; Bias; Blood lipids; Butter; Cardiovascular disease; Chi-square test; Child; Cholesterol, LDL - blood; Confidence; Counseling; Diet; dietary supplement; Dietary Supplements; Factorial design; familial hypercholesterolemia; Female; Food; Genetic aspects; Guar; Guar gum; Heterozygote; Humans; Hypercholesterolemia; Hyperlipoproteinemia Type II - blood; Hyperlipoproteinemia Type II - genetics; Intervention; Lipids; Lipids - blood; Low density lipoprotein; Low density lipoproteins; Male; Middle Aged; Mutation; Phytosterols; Plasma; Plasma levels; Publication Bias; Risk; Statistical tests; Systematic Review
• ISSN: 2072-6643; 2072-6643
• DOI: 10.3390/nu13010235

Conclusive data on the effectiveness of dietary interventions in heterozygous familial hypercholesterolemia (HeFH) management are unavailable. Whether this is due to a true lack of effects or biases in intervention designs remains unsettled. We systematically assessed the impact on LDL-C of published dietary randomized controlled trials (RCTs) conducted among individuals with HeFH in relation to their design and risk of bias. We systematically searched PubMed, Web of Science, and Embase in November 2020 to identify RCTs that assessed the impact of: (1) food-based interventions; (2) dietary counseling interventions; or (3) dietary supplements on LDL-C in individuals with HeFH. We evaluated the risk of bias of each study using the Cochrane Risk of Bias 2 method. A total of 19 RCTs comprising 837 individuals with HeFH were included. Of those, five were food-based interventions, three were dietary counseling interventions and 12 were dietary supplement-based interventions (omega-3, = 3; phytosterols, = 7; guar gum, = 1; policosanol, = 1). One study qualified both as a food-based intervention and as a dietary supplement intervention due to its factorial design. A significant reduction in LDL-C levels was reported in 10 RCTs, including eight dietary supplement interventions (phytosterols, = 6, omega-3, = 1; guar gum, = 1), one food-based intervention and one dietary counseling intervention. A total of 13 studies were judged to have some methodological biases in a way that substantially lowers confidence in the results. Studies at low risk of biases were more likely to report significant reductions in LDL-C concentrations, compared with studies at risk of bias (chi-square statistic: 5.49; = 0.02). This systemic review shows that the apparent lack of effectiveness of diet manipulation in modulating plasma levels of LDL-C among individuals with HeFH is likely due to biases in study designs, rather than a true lack of effects. The likelihood of reporting significant reductions in LDL-C was associated with the concurrent risk of bias.