Effectiveness of medical nutrition therapy in the management of adult dyslipidemia: A systematic review and meta-analysis

Cardiovascular disease (CVD) is a leading cause of mortality in the United States. Many primary risk factors, such as dyslipidemia and blood pressure, are modifiable with diet and lifestyle interventions. Therefore, the objective of this systematic review and meta-analysis was to evaluate the effectiveness of medical nutrition therapy (MNT) interventions provided by registered dietitian nutritionists (RDN) or international equivalents, compared to usual care or no MNT, on lipid profile and blood pressure (secondary outcome) in adults with dyslipidemia. The databases MEDLINE, CINAHL, Cochrane CENTRAL, and Cochrane Database of Systematic Reviews were searched for randomized controlled trials (RCTs) published between January 2005 and July 2021. Meta-analyses were performed using a random-effects model for lipid outcomes (seven RCTs, n=838), systolic blood pressure (SBP) (three RCTs, n=308), and diastolic blood pressure (DBP) (two RCTs, n=109). Compared to usual care or no intervention, MNT provided by RDNs improved total cholesterol (total-C) [mean difference (95% CI): -20.84 mg/dL (-40.60, -1.07), P=0.04]; low-density lipoprotein cholesterol (LDL-C) [-11.56 mg/dL (-21.10, -2.03), P=0.02]; triglycerides (TG) [-32.55 mg/dL (-57.78, -7.32), P=0.01];; and SBP [ -8.76 mm Hg (-14.06 lower to -3.45) P<0.01].High-density lipoprotein cholesterol (HDL-C) [1.75 mg/dl (-1.43, 4.92), P=0.28] and DBP [-2.9 mm Hg (-7.89 to 2.09), P=0.25] were unchanged. Certainty of evidence was moderate for total-C, LDL-C, and TG, and low for HDL-C, SBP, and DBP. In conclusion, in adults with dyslipidemia, MNT interventions provided by RDNs are effective for improving serum lipids/lipoproteins and SBP levels.