Successful Aging: A Neuroscientist Explores the Power and Potential of Our Lives

by Daniel J. Levitin

But where it really gets interesting is the effects that probiotics can potentially have on cognition, emotion, and behavior. Small-scale trials have shown that a single probiotic, Bifidobacterium infantis, can alleviate depression and anxiety, and a cocktail of Lactobacillus helveticus and Bifidobacterium longum can reduce cortisol levels—an indicator of stress. A preliminary report finds that a probiotic mixture containing Bifidobacterium lactis, Lactobacillus bulgaricus, Streptococcus thermophilus, and Lactobacillus lactis can substantially alter brain activity in the mid- and posterior insula, regions associated with anxiety disorders and attentional focus. Kefir, yogurt, and other fermented milk products containing probiotics have been shown to have a positive effect on mood and the brain’s emotional centers. And emerging evidence suggests that eating more fiber promotes gut health and microbiomic balance.