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Metabolic Effects of Monounsaturated Fatty Acid-Enriched Diets Compared With Carbohydrate or Polyunsaturated Fatty Acid-Enriched Diets in Patients With Type 2 Diabetes: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

ABSTRACT:

Objective

Dietary interventions in patients with type 2 diabetes (T2D) are important for preventing long-term complications. Although a healthy diet is crucial, there is still uncertainty about the optimal macronutrient composition. We performed a meta-analysis comparing diets high in cis-monounsaturated fatty acids (MUFA) to diets high in carbohydrates (CHO) or in polyunsaturated fatty acids (PUFA) on metabolic risk factors in patients with T2D.

Research design and methods

We systematically reviewed PubMed, MEDLINE, and Cochrane databases and prior systematic reviews and meta-analyses to identify interventions assessing HbA1c, fasting plasma glucose and insulin, LDL and HDL cholesterol, triglycerides, body weight, or systolic/diastolic blood pressure. Meta-analyses were conducted using both fixed- and random-effects models to calculate the weighted mean difference (WMD) and 95% CI.

Results

We identified 24 studies totaling 1,460 participants comparing high-MUFA to high-CHO diets and 4 studies totaling 44 participants comparing high-MUFA to high-PUFA diets. When comparing high-MUFA to high-CHO diets, there were significant reductions in fasting plasma glucose (WMD -0.57 mmol/L [95% CI -0.76, -0.39]), triglycerides (-0.31 mmol/L [-0.44, -0.18]), body weight (-1.56 kg [-2.89, -0.23]), and systolic blood pressure (-2.31 mmHg [-4.13, -0.49]) along with significant increases in HDL cholesterol (0.06 mmol/L [0.02, 0.10]). When high-MUFA diets were compared with high-PUFA diets, there was a significant reduction in fasting plasma glucose (-0.87 mmol/L [-1.67, -0.07]). All of the outcomes had low to medium levels of heterogeneity, ranging from 0.0 to 69.5% for diastolic blood pressure (Phet = 0.011).

Conclusions

Our meta-analysis provides evidence that consuming diets high in MUFA can improve metabolic risk factors among patients with T2D.

SUBMITTER: Qian F

PROVIDER: S-EPMC4955926 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Context:Current dietary guidelines for cardiovascular disease risk management recommend restricting intake of saturated fatty acids (SFAs). However, the optimal macronutrient profile, in the context of a low-SFA diet, remains controversial. The blood-pressure effect of replacing SFAs in diets with monounsaturated fatty acids (MUFAs) compared with carbohydrate has not been quantified to date. Objective:To synthesize the evidence for the effect of substituting a high-carbohydrate (high-CHO) diet for a high-monounsaturated fatty acid (high-MUFA) diet on blood pressure, a systematic review and meta-analysis of randomized clinical trials in a population without health restrictions was conducted. Data Sources:MEDLINE, EMBASE, and Cochrane Central Register of Controlled Clinical Trials were searched through June 7, 2017. Randomized controlled trials of >?3 weeks duration that assessed the effect of high-MUFA diets in isocaloric substitution for high-CHO diets on systolic blood pressure (SBP) and diastolic blood pressure (DBP) were included. Data Extraction:Data were pooled using the generic-inverse variance method with random effects models and expressed as mean differences (MDs) with 95% confidence intervals (CIs). Heterogeneity was assessed by Cochran Q statistic and quantified by the I2 statistic. The quality of the evidence was assessed with the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. Results:Fourteen trials (n?=?980 participants) were included in the analysis. Comparatively, the high-MUFA diets in isocaloric substitution for high-CHO diets did not demonstrate a greater reduction in blood pressure (SBP: MD, -0.08?mmHg [95%CI, -1.01 to 0.84], P?=?0.86; DBP: MD = 0.01?mmHg [95%CI, -0.73 to 0.75], P?=?0.98). The overall quality of the evidence was assessed as moderate. Conclusions:In the context of low SFAs, high-MUFA diets in isocaloric substitution for high-CHO diets did not affect blood pressure in individuals with and without hypertension. Large-scale trials achieving higher MUFA targets are required to support these findings. ClinicalTrials.gov ID:NCT02626325.

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