The FDA has concluded that "natural" flavors include those products derived from processes such as those used in corn refining. Corn syrup, high fructose corn syrup, and crystalline fructose are made from corn, a natural grain product, and are therefore consistent with the definition of natural.
Few reports included details of the study – and evidence from other studies – which suggest that high-fructose corn syrup (HFCS) is not worse, overall, than cane sugar (sucrose).