Health questionnaires and compliance control
Before the study started, volunteers were asked to fill in an on-line lifestyle and health questionnaire to monitor possible health problems and medication use and to check whether they met all the inclusion criteria and none of the exclusion criteria. In addition, volunteers completed a specific questionnaire during each intervention phase (weeks 5, 10, and 15) to monitor health status and capsule compliance.The capsules were packaged in blister packs of 15 units each. The batch number was specified on each blister. Each volunteer received a total of 45 capsules of the assigned batch at the beginning of each period. Compliance was calculated by asking how many capsules were consumed during each intervention period and counting the number of capsules that the volunteers had to return at the end of the two periods.