Effect of fructose on postprandial triglycerides: A systematic review and meta-analysis of controlled feeding trials

BACKGROUND: In the absence of consistent clinical evidence, concerns have been raised that fructose raises postprandial triglycerides. PURPOSE: A systematic review and meta-analysis was conducted to assess the effect of fructose on postprandial triglycerides. DATA SOURCES: Relevant studies were identified from MEDLINE, EMBASE, and Cochrane databases (through September 3, 2013). DATA SELECTION: Relevant clinical trials of ≥ 7-days were included in the analysis. DATA EXTRACTION: Two independent reviewers extracted relevant data with disagreements reconciled by consensus. The Heyland Methodological Quality Score (MQS) assessed study quality. Data were pooled by the generic inverse variance method using random effects models and expressed as standardized mean differences (SMD) with 95% confidence intervals (CI). Heterogeneity was assessed (Cochran Q statistic) and quantified (I(2) statistic). DATA SYNTHESIS: Eligibility criteria were met by 14 isocaloric trials (n = 290), in which fructose was exchanged isocalorically for other carbohydrate in the diet, and two hypercaloric trials (n = 33), in which fructose supplemented the background diet with excess energy from high-dose fructose compared with the background diet alone (without the excess energy). There was no significant effect in the isocaloric trials (SMD: 0.14 [95% CI: -0.02, 0.30]) with evidence of considerable heterogeneity explained by a single trial. Hypercaloric trials, however, showed a significant postprandial triglyceride raising-effect of fructose (SMD: 0.65 [95% CI: 0.30, 1.01]). LIMITATIONS: Most of the available trials were small, short, and of poor quality. Interpretation of the isocaloric trials is complicated by the large influence of a single trial. CONCLUSIONS: Pooled analyses show that fructose in isocaloric exchange for other carbohydrate does not increase postprandial triglycerides, although an effect cannot be excluded under all conditions. Fructose providing excess energy does increase postprandial triglycerides. Larger, longer, and higher-quality trials are needed. PROTOCOL REGISTRATION: ClinicalTrials.gov identifier, NCT01363791.