During the 1950 – 1970 a series of independent observational studies suggested that dietary fiber intake was associated with a number of health benefits dietary fiber as a class of compounds includes a mixture of plant carbohydrate polymers both oligosaccharides and polysaccharides e.g. cellulose hemicelluloses pectic substances guns resistant starch inulin that may be associated with lignin and non-carbohydrate component e.g. polyphenols waxes saponins cutin phytates resistant protein