Heterogeneous Effects of Fructose on Blood Lipids in Individuals With Type 2 Diabetes Systematic review and meta-analysis of experimental trials in humans

OBJECTIVE - Because of blood lipid concerns, diabetes associations discourage fructose at high intakes. To quantify the effect of fructose on blood lipids in diabetes, we conducted a systematic review and meta-analysis of experimental clinical trials investigating the effect Of isocaloric fructose exchange for carbohydrate on triglycerides, total cholesterol, LDL cholesterol, and HDL cholesterol in type I and 2 diabetes. RESEARCH DESIGN AND METHODS - We searched MEDLINE, EMBASE, CINAHL, and the Cochrane Library for relevant trials of >= 7 days. Data were pooled by the generic inverse variance method and expressed as standardized mean differences with 95% Cl. Heterogeneity was assessed by chi(2) tests and quantified by I-2. Meta-regression models identified dose threshold and independent predictors of effects. RESULTS - Sixteen trials (236 subjects) met the eligibility criteria. Isocaloric fructose exchange for carbohydrate raised triglycerides and lowered total cholesterol under specific conditions Without affecting LDL cholesterol or HDL cholesterol. A triglyceride-raising effect without heterogeneity was seen only in type 2 diabetes when the reference carbohydrate was starch (mean difference 0.24 [95% CI 0.05-0.44]), dose was >60 g/day (0.18 [0.00-0.37]), or follow-up was <= 4 weeks (0.18 (0.00-0.35]). Piecewise meta-regression confirmed a dose threshold of 60 g/day (R = 0. 13)/10% energy (R = 0.36). A total cholesterol-lowe ring effect without heterogeneity was seen only in type 2 diabetes under the following conditions: no randomization and poor study quality (-0. 19 [-0.34 to -0.05]), dietary fat >30% energy (-0.33 [-0.52 to -0. 151), or crystalline fructose (-0.28 [-0.47 to -0.091). Multivariate meta-regression analyses were largely in agreement. CONCLUSIONS - Pooled analyses demonstrated conditional triglyceride-raising and total cholesterol-lowering effects of isocaloric fructose exchange for carbohydrate in type 2 diabetes, Recommendations and large-scale future trials need to address the heterogeneity in the data.