Yogurt is a concentrated source of protein that comes with beneficial live cultures (aka probiotics), such as Lactobacillus acidophilus.
Whether you love Cheddar, Swiss or Parmesan, these cheeses are rich in protein, and aged cheeses in particular contain probiotics.
Fish—especially fatty fish like salmon, tuna, mackerel and sardines—are rich in omega-3 fatty acids.
Chicken and turkey are excellent sources of lean proteins. They contain amino acids such as glutamine and tryptophan, known to support a healthy microbiome.
Beans are a good source of fiber, an important nutrient that helps promote regular digestion and increase healthy bacteria in the GI tract.