2.6. Design of the Trial
The outline of the trial is presented on the flow chart (The supplementation of all participants started on 7 November upon signal given by the administrator. Over the first 15 days, the participants were asked to take 2 of the 500 mg sachets of supplementation material per day. One sachet in the morning and one in the evening, taken on empty stomach with water or with a teaspoonful of natural yoghurt. Then, for the next 30 days, they were asked to use just one sachet in the morning. After 45 days, the supplementation was suspended. The participants were asked to take 4 consecutive doses of supplementation material (twice daily for 2 days) just in case they observed symptoms of developing a URTI. Supplementation with 2 sachets per day was reinstated for an additional 7 days one week before the semester ended (at the day 87 of the trial), when most of the tests and exams concluding the semester would take place. After this last supplementation period, the daily reports were collected for an additional 14 days, and on 21 February, 107 days from beginning of supplementation, the trial was terminated.