Dietary fiber and prebiotics such as psyllium, acacia and inulin help support regularity and feed the beneficial bacteria that live in the gut. Shop fiber and prebiotic supplements in powders, capsules and gummies. Brands include NOW Foods, Vital Nutrients, Organic India and Pure Encapsulations. Compare forms, strengths and sizes, then add to cart. Shop with confidence: authentic supplements from an authorized retailer since 2010.