ness was determined before (week 0), during (week 0), and at the end (week 0) of the intervention period, and at two week follow-up (week 0), using a handheld reflectance spectrophotometer. Solid line indicates the intervention group, dashed line indicates the control group, error bars represent the standard error of the mean.](pone.0000000.g000){#pone.0000000.g000}  