Our gastrointestinal tracts are home to an estimated 500 species of bacteria, also known as probiotics (translated as “for life”). Though it might sound gross, these probiotic bacteria boost immune function by preventing disease-causing invaders from crossing the intestinal wall and entering the bloodstream—that’s why 80 percent of our immune system is located in the gut. Lactobacillus acidophilus is the main inhabitant of your small intestine. This bacteria manufactures lactic acid, which suppresses the overgrowth of harmful bacteria and yeast. Meanwhile, in the large intestine, bifidobacterium bifidum produces numerous specialized acids that prevent harmful viruses from colonizing. There are several ways you can support the healthy gut bacteria. The first way is by consuming cultured and fermented food products, including “live-culture” yogurt and kefir, tempeh, sauerkraut, and kimchi. Probiotics can also be taken in supplement form, and the optimal time is first thing in the morning on an empty stomach when stomach acid is at it’s lowest.