Soluble fibre: beans and lentils, oats, pulses, fruit and vegetables
Insoluble fibre: wholegrain bread and cereals, brown rice, fruit and vegetables
“Soluble fibre dissolves in water, forming a gel, and is fermented in the colon by bacteria to a greater extent than insoluble fibre. Short-chain fatty acids and gas are the active metabolites of soluble fibre, both of which decrease the gut transit time. In contrast, insoluble fibre undergoes minimal change in the digestive tract and shortens colonic transit, causing an increase in the faecal mass.”
Bijkerk C et al (2004), Systematic review: the role of different types of fibre in the treatment of irritable bowel syndrome. Alimentary Pharmacology & Therapeutics, 19: 245–251.