Statistical analysis Data are presented in text, tables, and figures as means ± SD with 95 % CI and p-values <0.05 were considered statistically significant. Student t-test was used in observational samples for normally distributed data. Wilcoxon matched pairs test was used when data were not normally distributed. Intervention samples were compared using a general linear model to test the statistical significance of differences between groups. A mixed model ANOVA was used to assess group × time interaction. Within each group time effects of the intervention were assessed using repeated measures ANOVA with Bonferroni's multiple comparison. Where there were only two data sets within each group (i.e. only baseline and intervention data as in data obtained from tissue biopsies) paired t-tests were used for normally distributed data and Wilcoxon test when data were not normally distributed. Pearson's correlation coefficient was calculated to express relationship between changes from baseline to intervention for normally distributed data and Spearman's correlation coefficient was calculated when data were not normally distributed. Statistica 9.0, StatSoft, Inc. USA was used to perform all statistical procedures.