The best sources of fibre are whole grains, fruits and vegetables. Dietary fibre is the edible parts of plants that are resistant to digestion and absorption in the small intestine, with complete or partial fermentation in the large intestine. Dietary fibre supplements often include polysaccharides, oligosaccharides, lignin and associated plant substances. According to the Harvard School of Public Health, children and adults should get a minimum of 20 grams of fibre daily. Always consult your healthcare professional before taking a fibre supplement if you are unsure.