Anti-inflammatory Probiotics in Cognitive Functioning

The goal of this study is to explore the potential impact of an anti-inflammatory probiotic mixture of psychobiotics including Bifidobacterium longum Rosell®-175 and Lactobacillus helveticus Rosell®-52 on cognitive functions in older adults following either pro-inflammatory or anti-inflammatory diets. According to recent findings, even short-term exposure to foods with pro- or anti-inflammatory properties may lead to corresponding negative or beneficial effects on cognitive functioning . The main questions this study aims to answer are: * How important is the initial dietary pattern for observing possible beneficial effects of probiotic supplementation? (Diet as a potential moderator) * How important is the initial state of the gut microbiota for observing possible beneficial effects of probiotic supplementation? (Microbiota as a potential moderator) * Is it possible to improve or slow down the decline in cognitive functions associated with aging with probiotic supplementation? * Can probiotic supplementation counteract the negative effects of pro-inflammatory dietary patterns? The investigators will compare probiotic to a placebo (a look-alike substance that contains no active ingredients) to determine whether probiotic is effective in enhancing cognitive function. Participants: * Take a probiotic or placebo capsule daily for 3 months * Undergo a crossover after 3 months - those who initially took probiotics will switch to the placebo, and vice versa * Visit SWPS University for screening (T0), baseline assessments before beginning supplementation (T1), and follow-up assessments at 3 months (T2) and 6 months (T3). The T2 visit occurs just before the crossover. * Complete neuropsychological testing, questionnaires, and EEG recordings during the T1, T2, and T3 visits. * Provide stool samples for gut microbiota analysis at the T1, T2, and T3 visits. * Maintain their usual dietary habits throughout the study.