Germany: Findings from a meta-analysis suggest that regular consumption of reformulated bread "healthier" bread variants may improve fasting blood sugar in patients with type 2 diabetes mellitus (T2DM). Reformulated bread variants are high in whole grains, dietary fibre, and functional ingredients.
The findings were published online in January 2023 issue of the journal Advances in Nutrition.
Bread is a significant source of grain-derived carbohydrates. High consumption of refined grains, high glycemic index and low dietary fibre, are tied to an increased risk for type 2 diabetes and other chronic diseases. Hence, improvements in bread composition could influence population health.
Bread is a significant source of grain-derived carbohydrates worldwide. High intakes of refined grains, low dietary fibre and high glycemic index are linked with increased risk for T2DM and other chronic diseases. Hence, improvements in bread composition could impact population health.
In line with the WHO's food reformulation definition (altering the composition or processing of a beverage or food product to improve its nutritional profile or to reduce its nutrients of concern or content of ingredients), the researchers of the study used the term "reformulated bread" for all these approaches.
Meta-analyses, to date, have addressed the effect of dietary fibre, whole-grain consumption, and glycemic index on metabolic health parameters. According to the authors on this topic, no other systematic reviews and meta-analyses have been published. However, considering the paradigm shift from nutrient-based guidelines toward food-based dietary guidelines, a direct appraisal is warranted on the relevance of modified bread as a food group on glycemic control.
Against the above background, Alena M. Schadow from Paderborn University in Paderborn, Germany, and colleagues aimed to evaluate the effect of regular "reformulated bread" consumption on glycemic control among healthy adults, adults at cardiometabolic risk or with manifest T2DM in a systematic review.
For this purpose, the researchers performed a literature search using online databases. Eligible studies employed a bread intervention for more than two weeks in adults (at cardiometabolic risk, manifest T2DM or healthy) and reported glycemic outcomes (fasting insulin, fasting blood glucose, HbA1c, postprandial glucose responses, and HbA1c). Data were pooled and presented as mean difference (MD) or standardized MD between treatments.
Twenty-two studies comprising 1037 participants met the inclusion criteria.
The authors reported the following findings:
Consumption of reformulated intervention breads compared with "regular" or comparator bread led to lower fasting blood glucose concentrations (MD: −0.21 mmol/L, moderate certainty of evidence), yet no differences in fasting insulin (MD: −1.59 pmol/L, moderate certainty of evidence), HOMA-IR (MD: −0.09, moderate certainty of evidence), HbA1c (MD: −0.14, very low certainty of evidence), or postprandial glucose response (SMD: −0.46, low certainty of evidence).
Subgroup analyses showed a beneficial effect for fasting blood glucose only among people with type 2 diabetes (low certainty of evidence).
The research showed a beneficial effect of reformulated bread on fasting blood glucose concentrations in adults, primarily among T2DM patients.
"Our findings indicate that bread quality is relevant for metabolic health in adults and that future research should address its significance among people at risk of T2DM," the authors concluded.
Reference:
Schadow, A. M., Revheim, I., Spielau, U., Dierkes, J., Schwingshackl, L., Frank, J., Hodgson, J. M., Moreira-Rosário, A., Seal, C. J., Buyken, A. E., & Rosendahl-Riise, H. (2023). The Effect of Regular Consumption of Reformulated Breads on Glycemic Control: A Systematic Review and Meta-Analysis of Randomized Clinical Trials. Advances in Nutrition, 14(1), 30-43. https://doi.org/10.1016/j.advnut.2022.10.008