So sorry for the very late reply. I hadn't receive any notification that you had posted a question and only saw it now.
The dietary condition consisted of a target of 7 serves of high prebiotic foods per day, with the remainder of diet as per participant's discretion. This was compared with a control group on their existing (low-prebiotic diet). In addition to the diet vs no-Diet factor, we had a probiotic supplement vs placebo supplement factor. There was no manipulation of micronutrients.
Individuals with fibromyalgia were eligible to participate as long as they did not have a concurrent psychiatric diagnosis as were were targeting people with subclinical depression and/or anxiety. However, as it turns out, no one with fibromyalgia participated in the trial.