The study will be carried out over a 22-week period, during which the participants will consume an oral probiotic for 10 weeks and a placebo (an inert substance with no therapeutic effect) for 10 weeks, with a two-week washout period in between. Participants will receive either the probiotic or the placebo for the first ten weeks and the other for the second 10 weeks. Neither the participant nor the researcher administering the probiotics and placebos will be aware which one the participant is taking. Because this a double-blind design, only the supervisor, Dr. Susan Potter, will be privy to the experimental condition of the participants. The supervisor will randomly assign participants to either a placebo or probiotic condition.