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BACKGROUND	Epidemiology associates whole-grain ( WG ) consumption with several health benefits .
BACKGROUND	Mounting evidence suggests that WG wheat polyphenols play a role in mechanisms underlying health benefits .
OBJECTIVE	The objective was to assess circulating concentration , excretion , and the physiologic role of WG wheat polyphenols in subjects with suboptimal dietary and lifestyle behaviors .
METHODS	A placebo-controlled , parallel-group randomized trial with 80 healthy overweight/obese subjects with low intake of fruit and vegetables and sedentary lifestyle was performed .
METHODS	Participants replaced precise portions of refined wheat ( RW ) with a fixed amount of selected WG wheat or RW products for 8 wk .
METHODS	At baseline and every 4 wk , blood , urine , feces , and anthropometric and body composition measures were collected .
METHODS	Profiles of phenolic acids in biological samples , plasma markers of metabolic disease and inflammation , and fecal microbiota composition were assessed .
RESULTS	WG consumption for 4-8 wk determined a 4-fold increase in serum dihydroferulic acid ( DHFA ) and a 2-fold increase in fecal ferulic acid ( FA ) compared with RW consumption ( no changes ) .
RESULTS	Similarly , urinary FA at 8 wk doubled the baseline concentration only in WG subjects .
RESULTS	Concomitant reduction in plasma tumor necrosis factor - ( TNF - ) after 8 wk and increased interleukin ( IL ) -10 only after 4 wk with WG compared with RW ( P = 0.04 ) were observed .
RESULTS	No significant change in plasma metabolic disease markers over the study period was observed , but a trend toward lower plasma plasminogen activator inhibitor 1 with higher excretion of FA and DHFA in the WG group was found .
RESULTS	Fecal FA was associated with baseline low Bifidobacteriales and Bacteroidetes abundances , whereas after WG consumption , it correlated with increased Bacteroidetes and Firmicutes but reduced Clostridium .
RESULTS	TNF - reduction correlated with increased Bacteroides and Lactobacillus .
RESULTS	No effect of dietary interventions on anthropometric measurements and body composition was found .
CONCLUSIONS	WG wheat consumption significantly increased excreted FA and circulating DHFA .
CONCLUSIONS	Bacterial communities influenced fecal FA and were modified by WG wheat consumption .
CONCLUSIONS	This trial was registered at clinicaltrials.gov as NCT01293175 .

