Fatigue is a common and often debilitating companion for people with inflammatory bowel conditions. Now, a study provides insight into why vitamin B1—also known as thiamine—helps some patients regain their energy, while others do not experience the same effect. The study shows, among other things, that patients' response to vitamin B1 depends on gut bacteria, with researchers focusing particularly on a specific "good bug" that seems to play a crucial role. "We know that about half of the fatigued patients benefit from treatment with vitamin B1, but we haven't been able to find anything that distinguishes those who had an...