Bland-Altman plot comparing energy intake measured using indirect calorimetry (kcal/d) and energy intake calculated from the dietary records (kcal/d).

<p>Mean energy intake measured by calorimetry and dietary record are plotted against the difference between energy intake measured by calorimetry and by dietary record.</p

Summary of the parameters of colonic metabolism and toxicity.

<p>All values are expressed as median (IQR) (n = 20). Parameters with different letters (a, b, c) in superscript were significantly different between the dietary interventions. Friedman and Wilcoxon tests were used to evaluate the results, except for urinary ¹⁵N and p-cresol, and fecal ¹⁵N. Due to missing values an unstructured linear mixed model was applied using treatment as fixed effect. P-values refer to Friedman tests.</p

Score plots showing clustering of the metabolite profiles analyzed using PLS-DA according to genotoxicity (A) and cytotoxicity (B).

<p>(A) High genotoxicity samples are located on the right side of the score plot, while low genotoxicity samples are present on the left side, indicating a difference in VOC profile between high and low genotoxicity samples. (B) High cytotoxicity samples are present on the upper right side of the score plot and low cytotoxicity samples on the lower left side, indicating a difference in VOC profile between high and low cytotoxicity samples.</p

Main metabolic pathways for the production of microbial metabolites.

<p>VOC are shown in bold <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0052387#pone.0052387-Welberg1" target="_blank">[52]</a>.</p

Scatter plot in which cytotoxicity (IC50) is plotted against urinary p-cresol excretion (mg/24 h).

<p>The plot shows a negative correlation between both parameters (Spearman’s r = −0.435, p = 0.001).</p

Scatter plot of the comparison between urinary p-cresol excretion (mg/24 h) and absolute protein intake (g/24 h).

<p>Urinary p-cresol excretion correlated positively with absolute protein intake (Spearman’s r = 0.371, p = 0.007).</p

Enrollment of the volunteers.

<p>Enrollment of the volunteers.</p

Summary of dietary records and validating measures in urine.

<p>All values are expressed as medians (IQR) (n = 20). Parameters with different letters (a, b, c) in superscript are significantly different between the dietary interventions, test. Friedman and Wilcoxon tests were used to evaluate the results, except for urinary N and urea. Due to missing, values an unstructured linear mixed model was applied using treatment as fixed effect. P-values refer to Friedman tests.</p

Protein intake and phenolic metabolites.

<p>Influence of a high vs. low protein diet on change in plasma level and 24h urinary excretion of phenolic metabolites.</p

Protein intake and urea.

<p>Influence of a high vs. low protein diet on change in plasma urea and 24h urinary excretion of urea.</p