A natural growth promoting peptide comprising a growth promoting fragment of a protein selected from SEQUENCE ID NO's: 1 to 13, and a composition comprising a plurality of growth promoting peptides, is described. Also disclosed is the use of the peptides and compositions in prevention of ageing of human skin, treatment of diseases or conditions characterised by damaged epithelial cells or tissue such as colon cancer and peripheral inflammatory disorders, and wound treatment. Specific pea protein derived peptides are described in SEQUENCE ID NO'S 15 to 215 and 283 to 340, and specific rice protein derived peptides are described in SEQUENCE ID NO'S 216 to 282 and 341 to 412.