TNF and Alzheimer disease: In congruence with this, a recent study observed that probiotic supplementation with kefir at the minimum dose of 2 ml/kg for 90 days influenced CNS function via the gut–brain axis, impacting positively on brain function (ameliorating memory, language, visual-spatial function, executive functions, conceptualization and abstraction abilities), systemic pro-inflammatory cytokines (downregulating IL-1, IL-6, IL-8, IL-12 and TNF-α), systemic antioxidant enzymes (upregulating GSH, GPx and SOD) and DNA repair/apoptosis (enhancing PARP-1 and p53 expression) in elderly patients with AD [247].