Modern-day expressions suggest we're innately attuned to the relationship between our brain and our gut. When we're nervous, we might say we have "butterflies." When we make a decision, we often attribute it to a "gut feeling." Indeed, science supports the notion that the gut and brain are intricately connected and that problems in the digestive tract such as gut inflammation can influence your mood in meaningful ways, says Jun Huh, an associate professor of immunology at Harvard Medical School