The recent discovery of the gut-brain axis has brought a deeper understanding to how digestion and food affects our mood and health. Journalist and nutritionist Allison Clark explains the gut-brain axis and offers practical suggestions on how you can improve it – and therefore your health – by adapting your diet.    Ever wonder why you have butterflies when you’re nervous? Or why you feel like you have a knot in your stomach when you’re sad? Or, perhaps, why stress or anxiety trigger d