Rather than being confined to a particular organ, about 80% of your immune system resides in your gastrointestinal tract in the form of receptor cells. Because of this prime location, what happens in your gut influences your immune function and thus your health.
When your gut is healthy, you have a large, thriving community of beneficial or friendly bacteria, or probiotics, supporting your immune system receptor cells. They help form a protective barrier within your colon and intestines. Ideally, you want about 85 percent of your gut bacteria to be populated by the beneficial type.
Optimizing and supporting the beneficial bacteria in your gut is one of the most powerful things you can do for your health and well-being, as the beneficial gut microbes influence many functions in your body. Benefiting your body from head to toe, research suggests taking a probiotic supplement may be even more important than taking a daily multivitamin.