Meta-analysis of Whole-Grain Consumption and Biomarkers of Systemic Inflammation: Methodologic Limitations

Abstract

I read with interest the meta-analysis by Rahmani et al. (1), which indicated no differences in serum concentrations of inflammatory biomarkers including high sensitive C reactive protein, IL-6, and TNF-α in randomized controlled trials comparing diets high in whole grains with diets low in whole grains. However, there are some methodological limitations that must be considered in the interpretation of these findings. First, Rahmani et al. excluded the study by Durazzo et al. (2) because of its quasi-experimental design, although that was a randomized double-blind crossover study, in which participants in the control group consumed refined grains for 4 wk, and 2 phases of the study were separated with a 2-wk washout period.