To examine the cognitive and metabolic effects of a probiotic supplement that is readily and already available for purchase in public drug stores. This study is a double-blinded randomized cross-over placebo-controlled intervention study. Participants will be randomized to receive either the probiotic supplement or the placebo during the first intervention period which will last 2 weeks. This will be followed by a washout period, after which they will proceed to the second intervention period, also lasting 2 weeks and also followed by a washout period.