High microbiota-accessible carbohydrates intake improves cardiometabolic risk factors in T2D

Greater intake of microbiota-accessible carbohydrates (MACs) leads to improvement in glycaemic control, blood lipid, body weight, and inflammatory markers for individuals with type 2 diabetes (T2D) relative to lower MACs intake, a study has shown.

The investigators searched the databases of Medline, Embase, and Cinahl for randomized controlled trials (RCTs) assessing the effect of MACs on cardiovascular risk factors in T2D patients. They used random-effects models in the meta-analysis to calculate pooled estimates, as well as performed sensitivity analyses, meta-regression, subgroup analyses, and Egger’s test.

For the umbrella review, pooled estimates, 95 percent confidence intervals (CIs), heterogeneity, and publication bias were summarized. Finally, the investigators used the Grading of Recommendation Assessment, Development, and Evaluation (GRADE) and modified NutriGrade to examine the quality of evidence in the meta-analysis and umbrella review, respectively.

The meta-analysis included 45 RCTs with a total of 1,995 participants.

With a moderate-to-high quality of evidence, high MAC intake led to a significant reduction in glycated haemoglobin (weighted mean difference [WMD], –0.436 percent, 95 percent CI, –0.556 to –0.315), fasting glucose (WMD, –0.835 mmol/L, 95 percent CI, –1.048 to –0.622), total cholesterol (WMD, –0.293 mmol/L, 95 percent CI, –0.397 to –0.190), triglycerides (WMD, –0.118 mmol/L, 95 percent CI, –0.308 to –0.058), body mass index (WMD, –0.476, 95 percent CI, –0.641 to –0.312), and systolic blood pressure (WMD, –3.066 mm Hg, 95 percent CI, –5.653 to –0.478) compared with low MAC intake.

The key variables were as follows: region, dose, and type of MAC.

Of note, 26 meta-analyses with 158 pooled estimates were included in the umbrella review of all dietary interventions for cardiovascular risk factors in T2D patients. There was moderate to high evidence quality of MACs, dietary fibre, high-protein diet, n-3, viscous fibre, vitamin D, and vitamin E intake.

“MACs are critical substrates for intestinal microbes,” the investigators said. “[T]he subsequent production of short-chain fatty acids may have some potential benefits for [T2D] patients.”